Dr Ash Ahmed

Paper crumb (PC) is a type of paper sludge residue from the wastepaper recycling industry. It is a by-product from the various fiber purification stages that is particularly composed of short cellulose fibers, lignin, organic compounds and inorganic filler residues. Despite representing a reject material for the paper recycling sector, this feedstock can be turned into a bioresource to enable cross-sector industrial symbiosis in the form of a more sustainable concrete, hence an opportunity for novel Net Zero supply chains. This study sought to valorise the PC by the sequential anaerobic digestion to produce methane (CH4) from the organic compounds, followed by utilization of the digestate as a water replacement in concrete. The 21-day digestion of PC yielded 163 ml CH4 per gram volatile solids and the resulting digestate improved concrete compressive strength up to 50% water replacement grade, meeting the requirements for structural grade (C32/40) applications with substitution grades up to 50% and 25%, with and without the addition of plasticiser respectively. In a minor capacity, the digestate reduced workability of the concrete mix, however we demonstrate this issue can be resolved by the addition of plasticiser or increased water to cement ratios. The admixture addition is important to facilitate pumpability on site and ensure satisfactory compaction. This study highlights the potential of anaerobic digestate as a concrete supplement (additive), which would improve the sustainability of both the construction and the paper sector.

Laboratory investigation was conducted focused on the utilisation of waste materials comprising Class F fly ash (FA) and rice husk ash (RHA), in roller compacted concrete (RCC) for pavement applications. The mixtures of RCC comprised CEM I 52.5 N Portland cement containing 0%, 5%, 10%, 20% and 30% wt FA or RHA. Various aggregate characteristics were measured to determine their suitability for road applications. Compaction tests were done to obtain values of optimum moisture content for RCC mixtures. The mechanical properties investigated comprised compressive strength, static modulus of elasticity, dynamic modulus of elasticity and ultrasonic pulse velocity. Results showed that proportions of up to 5–10% wt RHA or FA were optimal and can be recommended for incorporation in RCC pavement mixtures. Standard models giving the relationships between compressive strength, static and dynamic elastic moduli of normal concretes, were found to be also applicable to RCCs.

Abstract

An experimental study was conducted to evaluate the effects of crumb rubber (CR) on mechanical properties of roller compacted concrete (RCC) for use in pavements. In the experiment, proportions of 0%, 10%, 20% and 30% by volume (vol) CR, were incorporated into RCC as sand replacement material. Mixtures were made at cement contents of 275 kg/m3 (11%) and 201 kg/m3 (8.6%). The water content quantities used to prepare RCC mixtures, were determined from the moisture—dry density relationship obtained based on the soil compaction approach. Various mechanical properties were measured comprising compressive strength, splitting tensile strength, ultrasonic pulse velocity, static and dynamic moduli of elasticity. Also measured were pore-related physical tests consisting of water absorption and volume of permeable pores. It was found that cement content has significant influence on the amount of CR that can be suitably utilized in RCC mixtures. The RCCs prepared at the adequate cement content of 275 kg/m3, exhibited suitable performance for all mixtures containing up to 20% vol CR content. Results showed that the standard relationships between compressive strength, static and elastic moduli as established for normal concretes, are also applicable to RCCs.

Durability of concrete is defined as its ability to resist deterioration after it has been exposed to the environment of its intended use. This work examined the performance of combined (ternary) Pulverised Fuel Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) concrete in sulfate solutions of sodium sulfate (Na2SO4), magnesium sulfate (MgSO4) and mixed Na2SO4 and MgSO4, as well as its performance in water absorption. Investigations were carried out on replacements that were found to have achieved the highest compressive strengths as well as on 30% replacements from a previous study. From the results obtained, it was also found that at highest compressive strengths, the ternary concrete could be used with an advantage over the individual binary concretes in MgSO4 environments, whereas at a higher replacement, the ternary concrete could be used with an advantage over individual binary specimens in Na2SO4 and MgSO4 environments. For visual observations, it was concluded that the ternary concrete could be used with an advantage over the individual binary concretes in Na2SO4 and MgSO4 environments, whereas for strength deterioration, the results showed that the ternary specimens could be used with an advantage over individual binary concretes in both the MgSO4 and the mixed sulfate solutions. Generally, the ternary specimens showed some complimentary effect from the two materials.

Different supplementary cementitious materials are often blended with cement to produce sustainable concrete. More often than not, the strength of blended concrete is compromised, if the constituent materials are not carefully selected. In this study, optimization of strength properties of blended cement-rice husk ash (RHA) was carried out to determine the best mix ratio that produced binary blended concrete of high strength. Different mix ratios of cement and RHA were studied at a water cement ratio of 0.4 to produce concrete specimens. RHA was produced by burning 700 ℃ for an hour and its chemical composition was determined using the X-Ray Fluoresce (XRF) technique. RHA produced was used to replace cement at replacement levels of 2.5, 5, 7.5, and 10 %, and was used as binder. The compressive strength of each concrete mix was determined at 7, 28, and 56 days. Approximately 250 concrete cubes were tested and the results were subjected to statistical analysis. The results showed that compressive strength and internal structure varied with RHA as a replacement for cement. Optimal strength was achieved for a concrete mixture, prepared at a water: cement: aggregate ratio of 1:1.5:3, respectively, and a RHA replacement ratio of 5 %. HIGHLIGHTS Cement is the most utilized construction material. The energy-intensive processes that are involved in its production contribute up to 10 % of total global CO2emissions, with potentially adverse environmental implications. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of clinker, and in its place utilising supplementary cementitious materials (SCMs) or pozzolans Currently, most sustainable concrete uses either GGBS (slag) or PFA (fly ash) to reduce the quantity of cement used in construction and highways applications. GGBS and PFA come from industries (steel and coal waste respectively) which are in decline that should not be relied upon in the long term. Therefore, for long term sustainability it is imperative to focus attention on other alternative pozzolans This report shows that cement in concrete can also be replaced with rice husk ash (RHA) which actually enhances the mechanical properties. Findings show the usage of up to 5 % rice husk ash as a partial cement replacement can enhance the strength of concrete whilst reducing the embodied CO2

The latest addition to the Oxford Paperback Reference series, this A to Z is the most up-to-date dictionary of building, surveying, and civil engineering terms and definitions available.Written by an experienced team of experts in the ...

Materials Science in Construction explains the science behind the properties and behaviour of construction's most fundamental materials (metals, cement and concrete, polymers, timber, bricks and blocks, glass and plaster). In particular, the critical factors affecting in situ materials are examined, such as deterioration and the behaviour and durability of materials under performance. An accessible, easy-to-follow approach makes this book ideal for all diploma and undergraduate students on construction-related courses taking a module in construction materials.

The highway pavement is the biggest structural asset a government can construct and maintain. Concrete rigid pavements are used to carry traffic in large volumes across countries safely and efficiently. The performance of the concrete pavement is vital for ensuring a successful economy. Pavement quality concrete mixes have high levels of portland cement which contributes to a large proportion of CO2 emissions in the UK and across the globe. Currently the UK specifies ground granulated blastfurnace slag (GGBS) and pulverised fuel ash (PFA) to reduce the quantity of portland cement used in pavement construction. GGBS and PFA come from heavy industry; which are industries that should not be relied upon to improve the sustainability of construction materials. This report shows that cement in pavement quality concrete can be replaced with rice husk ash without causing adverse effects to the mechanical properties required for highways. Rice husk ash comes from the food production industry and is vital for the growing global population. It is seen that this is a socially responsible objective to use a pozzolan in highway pavement construction that is sourced from an environmentally friendly industry. The report investigates the resultant compressive and tensile strength of rice husk ash mixes and compares them to existing pavement quality mixes already used and specified. The report found that sieving rice husk ash and not grinding it gives the best performance. Due to the low density of rice husk ash the investigation found that replacing cement by volume rather than weight provided the best results. The investigation found that CEM II/A-LL 32,5R mixed with 20% rice husk ash meets the required specification for pavement quality concrete and mitigates using the comparative CEM I 52,5R mix. The investigation also notes that rice husk ash is observed to be more reactive with CEM II/A-LL 32,5R rather than CEM I 52,5R and suits early strength gains required for pavement construction. The report concludes that rice husk ash is a sustainable material that reduces the embodied CO2 of pavement quality concrete, which is well suited for building motorways to UK highway specifications and has the potential to improve the lives of people living in communities in rice growing countries across the globe.

The characteristic flexural strength of low density aircrete wallettes (2.8 and 2 N/mm

2

Durability of concrete is defined as its ability to resist any form of deterioration, allowing it to retain its original form and quality after exposure to the environment of its intended use. Permeability is the most important aspect of durability and service lives of concrete structures, and is measured by the ease with which a gas or liquid can get into and pass through concrete, or rate at which water under pressure can flow through interconnected voids within concrete. It has been suggested that pozzolanic reactions from Supplementary Cementitious Materials (SCMs) help in filling up pores using the Calcium Silicate Hydrate (C-S-H) gel that is formed during the secondary hydration of cement, through the reaction of calcium hydrixide [Ca(OH)2] with silicon dioxide (SiO2), which densifies the pore structure and transition zone, thereby reducing permeability from the packing effect of unreacted particles. This work investigated the water absorption performance of Corncob Ash (CCA), Anthill Soil (AHS) and Rice Husk Ash (RHA) concrete specimens. Tests were conducted on specimens that were found to have achieved the highest compressive strengths from strength tests and also on specimens that were made out of 30% (per cent) cement replacements. Results indicated that the water performance of all the three materials, including that of the ternary specimens of CCA and AHS were above those of the control specimens at highest compressive strength, and highlight the potential of using CCA, AHS and RHA at lower replacements to improve the durability of concrete.

The use of supplementary cementitious materials (SCMs) in concrete is established as cement production accounts for up to 10% of global CO2 emissions. However, Rice Hush Ash (RHA) is a relatively new SCM. This research investigated the effects of replacing CEM I & CEM II with RHA on the compressive, tensile, flexural strengths and workability of concrete primarily for usage in highway applications. CEM I and CEM II were replaced at 0 - 40%. The results showed a reduction in the workability of the concrete with increased replacement of RHA with CEM I and CEM II. Despite the poor workability, both mixes compacted well, without segregation or bleeding. The CEM II replaced concrete had a rapid strength gain, this is due to the compound C4AF in CEM II which is very reactive in the early stage and reacts beneficially with the silicate in the hydration process to form the strength giving compound calcium silicate hydrate. Most of the compressive strengths achieved for both CEM I & CEM II concrete were above the study’s target strength of Class C32/40 or CC37. Therefore RHA can enhance the performance of concrete and most importantly confer sustainability benefits.

Retrieval and reuse of crushed concrete aggregates (CCA) in the concrete industry is a common practice that has gained popularity due to environmental concerns that identify the saturation of landfill areas as a harmful and costly by-product of construction, and has therefore become a necessity for a sustainable, more well-coordinated effort towards improving concrete preparation. This research examines a natural method of CCA-washing that aims to effectively segregate contaminants from healthy material by allowing CCAs to sit outdoors for a period of time thus being subjected to several rain-washing cycles. Eleven mixes were prepared, a control mix with 100% natural/virgin concrete aggregates (NCA/VCA) and ten mixes with CCA content varying between 10-100% replacement. Findings showed that even up to 100% substitution a remarkable reduction of only 15% in compressive strength was observed, with no significant change or effect on the consistency; thus conferring potentially significant sustainability implications.

Cement is the most utilised construction material, and the second most consumed global commodity after water. Its demand has soared proportionately with the exponential rise in population to match required development. The heavily energy-intensive processes involved in its production contribute to about 7 to 10 per cent (%) of the total global emissions, with potentially adverse environmental implications and are expensive economically. These processes and those of concrete production consume heavily on natural resources such as sand, gravel, water, coal and crushed rock, the mining of which mars the environment. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of clinker, and in its place utilising Partial Cement Replacement (PCR) materials that require less process heating and emit fewer levels of carbon dioxide (CO ). This study investigated the ability of corncob ash to be used as a PCR, by testing for either pozzolanic Abstract 2 or cementitious properties. Experiments were carried out by replacing cement by weight in concrete mixes with corncob ash at 5%, 7.5%, 10%, 15% and 20% steps at the point of need. The results were compared with a control specimen made with no cement replacement. Durability was tested using the sulfate elongation test. The highest compressive strength was observed at the 7.5% replacement. However, higher replacement levels also showed impressive strengths suitable for structural applications. The sulfate elongation test results showed good performance for all corn cob ash specimens in comparison to the control mix. These findings showed good reproducibility and highlight the potential of corncob ash as an effective pozzolan.

s of Europe. In the UK, however, lack of availability has restricted the use of Low Density Aircrete. Developments in Eurocode 6 require adjustment to the UK design procedures, allowing greater utilization of Low Density High Performance Aircrete. The material has considerable advantages, which include its economical, mechanical and physical properties. It is usually manufactured using pulverized fuel ash, which is an industrial by-product. The potential for using Low Density Aircrete for the UK and indeed global construction industry is therefore highly promising with substantial economic and environmental benefits. Furthermore, calculations show the thermal insulating (shielding for hot climates) properties of this material.

Abstract—Cement is the most utilised material after water, and the processes that are involved in making it are energy intensive, contributing to about 7% of the total global anthropogenic carbon dioxide (CO2). Energy efficiency can however be achieved by using Supplementary Cementitious Materials (SCMs) such as Pulverised Fuel Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) which demand less process heating and emit fewer levels of CO2. This work examined the advantages of substituting cement using PFA and GGBS in ternary (2 SCMs) concrete at steps of 0%, 5%, 7.5%, 10%, 15%, 20%, 25%, and 30%. It was found that PFA increased the workability of GGBS, whereas GGBS improved the strength of PFA. The densities of the resultant concrete were below those of the 0% replacement as well as those of individual binary (1 SCM) concretes. The tensile strengths of the ternary concrete were lower than those of the binary concretes, whereas the gains in compressive strengths over curing time were higher at lower replacements for the ternary concrete compared with the 0% replacement and the binary concretes, but lower at higher replacements. The findings indicate that PFA and GGBS could be used together to improve the properties of concrete where each falls short.

Mortar for masonry is important because it provides the linkage between masonry units so enabling the composite to behave as a single material. The type of mortar used determines the flexural and compressive strength of the masonry. Nowadays most mortars used in construction are cement based. However, due to the heavily energy-intensive processes that are involved in its production the cement industry is responsible for up to 10% of global CO2 emissions; therefore, there are serious environmental implications with the usage and application of cement mortars. A sustainable alternative are lime mortars which have 30% less embodied CO2. Lime mortars confer benefits in comparison to cement based mortars such as accommodating a greater degree of wall movement and improved damp resistance. The main disadvantage with lime mortars is the longer setting time which can take up to 91 days in addition to the low strength. A way to overcome this is to add cement replacements (pozzolans). This paper investigates the properties of non-hydraulic (lime putty) lime mortar containing PFA (fly ash). Findings show a minimal amount of PFA addition of 2.5% doubles the mortar strength to 1 MPa within 28 days with an eventual strength of over 4 MPa achieved with 5% PFA. Therefore, non-hydraulic lime mortars with PFA offer a more sustainable alternative to cement based mortars without compromising setting time or strength whilst offering improved flexibility and breathability.

Cement is the most utilised construction material and the second most consumed commodity in the world after water. It has been reported that the heavily energy-intensive processes that are involved in its production contribute about 7 to 10% to the total global anthropogenic carbon dioxide (CO2), which is the main cause of global warming; and are expensive economically. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of cement, and in its place utilizing Supplementary Cementitious Materials (SCMs), which require less process heating and emit fewer levels of CO2. This work aimed to provide an original contribution to the body of knowledge by investigating the suitability of Anthill Soil (AHS) as an SCM by testing for pozzolanic or hydraulic properties. Cement was replaced in concrete with AHS by weight at 0%, 5%, 7.5%, 10%, 15%, 20%, 25%, and 30% steps at the point of need. The 0% replacement was used as the reference point from which performances were measured. The chemical composition analysis by X-ray diffraction (XRD) showed that AHS contained the required chemical composition for pozzolans, while the compressive strengths achieved were above strength classes that are specified as being suitable for structural applications. The increase in compressive strength over time, density and workability behaviors of AHS were consistent with the characteristics of SCMs. All results across the tests showed good repeatability, highlighting the potential of using AHS as an SCM in concrete to enhance the sustainability and economic aspect of concrete, while at the same time improving its properties in both the wet and hardened states.

Mortar for masonry is important because it provides the linkage between masonry units so enabling the composite to behave as a single material.  The type of mortar used determines the flexural and compressive strength of the masonry so in this paper, a range of mortars are examined and their effects on the flexural strength of low density block walls determined.  These include traditional designation (iii) (1 cement : 1 lime : 6 sand), designation (iv) (1 cement : 1 lime : 9 sand) mortars as defined in BS 5628, and two thin layer mortars. The conventional mortars were formed using both 42.5N or 32.5N PC to BS EN 197 in order to ascertain the difference these two cements have on the properties of mortar. The thin layer mortars show remarkably high compressive strength. The characteristic flexural strength of low density aircrete wallettes incorporating both these conventional and thin layer mortars was verified. The wallettes were tested in accordance with British and European standards. The flexural strength of aircrete wallettes was derived from the strength of small specimens tested to destruction under four-point loading. The strengths of the wallettes are high with impressive repeatability with the maximum strength being reached for thin layer wallettes within 7 days curing time. In general the strengths of both conventional mortar and thin layer mortar wallettes compare favourably to values reported in the standards.

Low Density Aircrete (Density ≤ 450 kg/m3 , compressive strength ≤ 3 N/mm2 ) has been used extensively for the construction of dwellings in many parts of Europe. In the UK, however, lack of availability has restricted the use of Low Density Aircrete. Recent developments in Eurocode 6 and the supporting CEN TC 125 standards require adjust ment to the UK design procedures, allowing greater utilisation of Low Density High Performance Aircrete. The material has considerable advantages, which include its economical, mechanical and physical properties. It is usually manufactured using pulverised fuel ash, which is an industrial by-product. The potential for using Low Density Aircrete for the UK and indeed global construction industry is therefore highly promising with substantial economic and environmental benefits. Furthermore, calculations show the termal insulating (shielding for hot climates) properties of this material. Keywords: Low Density Aircrete, Sustainable Masonry.

Cement is the most utilized construction material, and the second most consumed commodity in the world after water. Its demand has soared proportionately with the exponential rise in population in a bid to match the required development. The heavily energy-intensive processes that are involved in its production contribute to about 7 to 10 per cent (%) of the total global emissions, with potentially adverse environmental implications, and are also economically expensive. These processes, and generally those of the production of concrete consume heavily on natural resources such as sand, gravel, water, coal and crushed rock, mining of which mars the environment. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of clinker, and in its place utilising supplementary cementitious materials (SCMs) that require less process heating and emit fewer levels of carbon dioxide (CO2). This study investigated the ability of corncob ash (CCA) to be used as a SCM by testing for pozzolanic or hydraulic properties and performance in sulfate environments. Experiments were carried our by supplementing cement by weight in concrete mixes with CCA at 5%, 7.5%, 10%, 15%, 20%, 25% and 30% steps at the point of need. Results were compared with a control specimen, which was made with 100% cement. Durability was tested using the sulfate elongation test. The results showed impressive compressive strengths that were suitable for structural applications. It was concluded from the sulfate elongation test that CCA supplemented concrete could be used in aggressive environments with an advantage. The results showed good repeatability and highlight the potential of CCA as an effective pozzolan, which could enhance the sustainability and economic aspect of concrete, as well as improve its properties in both the wet and hardened states.

The dimensions and weight of machines, structures, and components that need to be transported safely by road are growing constantly. One of the safest and most widely used transport systems on the road today due to their versatility and configuration are modular trailers. These trailers have hydraulic pendulum axles that are that are attached in pairs to the rigid platform above. In turn, these modular trailers are subject to limitations on the load that each axle carries, the tipping angle, and the oil pressure of the suspension system in order to guarantee safe transport by road. Optimizing the configuration of these modular trailers accurately and safely is a complex task. Factors to be considered include the load’s characteristics, the trailer’s mechanical properties, and road route conditions including the road’s slope and camber, precipitation and direction, and force of the wind. This paper presents a theoretical model that can be used for the optimal configuration of hydraulic cylinder suspension of special transport by road using modular trailers. It considers the previously mentioned factors and guarantees the safe stability of road transport. The proposed model was validated experimentally by placing a nacelle wind turbine at different points within a modular trailer. The weight of the wind turbine was 42,500 kg and its dimensions were 5133 × 2650 × 2975 mm. Once the proposed model was validated, an optimization algorithm was employed to find the optimal center of gravity for load, number of trailers, number of axles, oil pressures, and hydraulic configuration. The optimization algorithm was based on the iterative and automatic testing of the proposed model for different positions on the trailer and different hydraulic configurations. The optimization algorithm was tested with a cylindrical tank that weighed 108,500 kg and had dimensions of 19,500 × 3200 × 2500 mm. The results showed that the proposed model and optimization algorithm could safely optimize the configuration of the hydraulic suspension of modular trailers in special road transport, increase the accuracy and reliability of the calculation of the load configuration, save time, simplify the calculation process, and be easily implemented.

Cement is the most utilized construction material, and the second most consumed commodity in the world after water. Its demand has soared proportionately with the exponential rise in population in a bid to match the required development. The heavily energy-intensive processes that are involved in its production contribute to about 7 to 10 per cent (%) of the total global emissions, with potentially adverse environmental implications, and are also economically expensive. These processes, and generally those of the production of concrete consume heavily on natural resources such as sand, gravel, water, coal and crushed rock, mining of which mars the environment. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of clinker, and in its place utilizing supplementary cementitious materials (SCMs) or pozzolans that require less process heating and emit fewer levels of carbon dioxide (CO2). This paper elaborates on the different types of chemical reactions taking place in concrete containing pozzolans as a partial cement replacement. A pozzolanic material relies on the secondary reaction following the hydration of cement, whereby it reacts with the free calcium hydroxide to form the calcium silicate hydrates (C-S-H) phase which is the major contributor to strength in concrete; as a result there is usually long term strength development up to and beyond 91 days in pozzolanic concrete. Due to the depleted levels of calcium hydroxide, pozzolanic concrete impart superior sulfate resistance.

Concrete is one of the most utilised materials in the world. It is used to construct buildings, bridges and highways and is comprised of four key ingredients: cement, sand, gravel, and water. Although, there are environmental implications regarding the use of concrete, e.g. high embodied CO2, it is a flexible material in that it is possible to incorporate waste materials whilst maintaining structural integrity. Very little work has been done in replacing or partially substituting water as the hydration of cement is a key reaction to strength development. This paper investigates the possibility of utilising wastewater sludge (WWS) from the brewery industry as a water substitute in concrete. With the adverse effects of climate change resulting in water shortages around the world, there are sustainable implications of finding water substitutes. Experiments were carried out by supplementing water by volume in concrete mixes with WWS at 25%, 50%, and 100% steps at the point of need. Results were compared with a control specimen, which was made with 100% pure water. The results showed impressive compressive strengths that were suitable for structural applications, even at 100% WWS content. The results showed good repeatability and highlight the potential of WWS as a water replacement, which could enhance the sustainability aspect of concrete.

Cement is the most utilised construction material and the second most consumed commodity in the world after water. It has been reported that the heavily energy-intensive processes that are involved in its production account for about 7 to 10 % of the total global anthropogenic carbon dioxide (CO2), which is the main cause of climate change; and are also expensive economically. Energy and cost efficiency can however be achieved by reducing on the amount of clinker, and in its place utilising pozzolans, which require less process heating and emit lower levels of CO2. This research aimed to provide an original contribution to the body of knowledge by investigating Anthill Soil (AHS) for pozzolanic properties. Cement was replaced in concrete with AHS by weight using 5% increments by weight, from 0 to 30% at the point of need. Durability was investigated using the water absorption and sulfate tests. Results of the chemical analysis by X-Ray Diffraction (XRD) showed that AHS contained the chemical composition required for pozzolans, and the compressive strengths achieved were for classes that are listed by standards as being durable and suitable for structural applications. The behaviour of AHS in workability, density, gain in compressive strength over time, water absorption and sulfate tests were also consistent with the characteristics of pozzolans, leading to a conclusion that it may be suitable for use as a pozzolan to improve the properties of concrete, reduce on the harmful effects of cement production to the environment and lower the overall cost of concrete, allowing for the construction of low cost buildings.

This work investigated the performance of ternary Corncob Ash (CCA) and Anthill Soil (AHS) in concrete mixes. CCA and AHS were replaced in concrete using equal proportions at replacements of 0%, 5%, 7.5%, 10%, 15%, 20%, 25%, and 30%. Investigations covered workability, density, compressive and tensile strengths and gain in strength over time of concrete, as these were found to be the major characteristics of Supplementary Cementitious Materials (SCMs). Results showed that the two materials could be used with an advantage over individual binary concretes in these areas.

Durability of concrete has been defined as its ability to withstand deterioration after it has been exposed to the environment of its intended use. This work examined the performance of ternary Corncob Ash (CCA) and Anthill Soil (AHS) concrete in sodium sulfate (Na2SO4), magnesium sulfate (MgSO4) and combined Na2SO4 and MgSO4 solutions. Bar specimens for elongation tests and cubes for strength deterioration tests were cast using combined CCA and AHS at the 5% replacement, which was earlier on reported to have achieved the highest compressive strength, as well as at the 30% replacement. From the findings, it was concluded that at the 5% replacement, the ternary mix could be used with an advantage over 100% cement concrete in MgSO4 environments.

Cement is the most utilized construction material. The energy-intensive processes that are involved in its production contribute up to 10% of total global CO2 emissions, with potentially adverse environmental implications. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of clinker, and in its place utilising supplementary cementitious materials (SCMs) or pozzolans that require less process heating and emit fewer levels of CO2. Currently, most sustainable concrete uses either GGBS (slag) or PFA (fly ash) to reduce the quantity of cement used in construction and highways applications. GGBS and PFA come from industries (steel and coal waste respectively) which are in decline that should not be relied upon in the long term. This report shows that cement in concrete can also be replaced with rice husk ash (RHA) which actually enhances the mechanical properties. RHA comes from the food production industry and is vital for the growing global population. It is thus a socially responsible objective to use a pozzolan in civil engineering applications that is sourced from an environmentally friendly and sustainable industry. This study investigated the potential of RHA to be used as a SCM by evaluating mechanical properties. Experiments were carried out by supplementing cement in concrete mixes with RHA at up to 10% replacement by mass. Results were compared with a control specimen (100% cement), with a water/binder (w/b) ratio of 0.4 and C32/40 design mix using CEM I. The results show excellent early age strengths with all RHA mixes surpassing 40 MPa strength within 7 days which is contrary to general trends in SCM concrete where strength development is slow in the initial stages in comparsion to 100% cement concrete. All RHA specimens exhibited impressive flexural and tensile strengths.

It has been argued that cement is the most energy intensive and expensive material in concrete. It has also been suggested that energy efficiency could be achieved by using Supplementary Cementitious Materials (SCMs), which require less process heating and emit fewer levels of CO2. This paper reviewed studies from different authors on the possibility of using Corn Cob Ash (CCA) as a SCM. The review targeted studies that had applied the quantitative method, with validity and reliability based on empirical data from laboratory experiments. The review covered workability, density, compressive and tensile strengths, gain in strength over time, water absorption and chemical resistance of CCA-replaced concrete. From the findings, it can be concluded that CCA could be used as an effective SCM to replace cement in concrete, with the benefit of a reduction in CO2 emissions that are associated with the production of cement and a mitigation on environmental nuisance that is attributed to the throwing away of corncobs and CCA in landfill, while at the same time improving the properties of wet and hardened concrete.

Fibre reinforced concrete (FRC) composites have been widely utilised in construction for a number of years to improve the performance of structural concrete. Incorporating agricultural/ industrial waste into the construction industry as FRC composites is a novel research field that can recycle and convert waste into valuable supplementary materials. In this study, concrete composites with fibres of coconut coir (CCF), wheat straw (WSF), and shredded fibres from waste plastic bottles (PETF) were evaluated and compared against the established use of polypropylene fibres (PPF) and steel fibres (SF). The study's objectives were set to attain the strength of 32-40 MPa (C32/40 grade) for using these waste fibres as alternatives in FRC. A concrete mix ratio of 1:2:3 with 1-2% waste fibres (CCF, WSF & PETF), 1-2% PPFC and 10% & 17% steel fibres were used to produce samples for testing on 7 & 28 days for evaluation of compressive, split tensile and flexural strengths. Generally, all FRC mixes with 1% fibre dosage exhibited an increase of compressive strength by 9 - 44% at 28 days. All fibre composites gave characteristic compressive strength of 40-60 MPa. Both the split tensile and flexural strength of all-fibre composites were generally improved with 1-2% fibres. flexural strength suggesting that fibre content should not exceed more than 2% of cement weight in composites. Shredded fibres of PET plastic bottles outperformed the established micro/macro PPF as PETF exhibited better flexural strength than PPF with both 1 and 2% dosages. The natural fibres of coir/wheat straw performed favourably compared to steel fibres (6.9 MPa). In conclusion, it is suggested that the optimum quantity of 1-2% of these novel alternative fibres after necessary treatment is feasible for the formulation of environmentally friendly fibre concrete composite with enhanced mechanical properties.

This paper focuses on the people’s knowledge, attitudes, and practices towards solid waste management in Nigeria. It evaluated the common solid waste management practices in the country and explored the strategies in place to promote sustainable waste management program. Using mixed method, the paper further evaluated the effectiveness of waste management implementation policies and the factors responsible for poor solid waste management. It was found that there is lack of environmental consideration in the attitudes and practices of managing waste in Nigeria. The paper concludes that the government needs to put in place strategies that will ensure public enlightenment programmes and campaign in order to make the public aware of the ganger of poor waste management to human health and social developmental activities. For these purposes, the following recommendations were made, firstly, the government should promulgate new laws to enforce environmental management compliance. Additionally, government should continue to enforce the existing laws on environmental practices. It is believed that when environmental pedagogy is embedded into the curriculum, will develop the consciousness for reduce, reuse and recycle.

A fundamental issue with the active ingredient of concrete, Portland cement, is its energy-intensive manufacturing process, which has led to the cement industry emitting up to 10% of global CO2 levels. To reduce the embodied CO2 in concrete, supplementary cementitious materials have been used to replace Portland cement and form cement-free binders. Portland cement has been replaced volumetrically with hydrated lime, metakaolin, and silica fume. Three well-established concrete mix design ratios were used for comparisons; 1-1-3, 1-2-3 and 1-1-2. Both metakaolin and silica fume were used to replace hydrated lime content at 10%, 30%, 50%, 70%, and 90%, and compared at curing ages of 7, 28 and 91-day curing ages to determine their characteristic compressive strength (fck) and characteristic flexural strength (fct, fl). Water curing was also compared at a 91-day curing age for the compressive strength compared with the air-cured samples. Results determined that HL 1-1-2 MK50 was the optimum design mix in terms of compressive and flexural strength with a compressive strength recorded of 11.7 MPa at 91 days of curing age and this was further increased to 13.2 MPa by immersing specimens in water. For mixes containing silica fume, it was determined that the optimum replacement was between 50 -70% with HL 1-1- 2 SF70, recording the highest compressive strength of 5.9MPa. Water curing increased the compressive strength above 50% silica fume replacement. This study aimed to target the BS 8500 standardized prescribed concrete classifications that range from 7.5-25 MPa, which outline applications for non-structural concrete usage.

Concrete, a ubiquitous material in modern construction, faces several fundamental issues, including the cement industry’s 8-10% anthropogenic CO2 emissions (CO2e), that can compromise its sustainability. Therefore, this paper explores novel material combinations of lower carbon binders. Performance issues considered were: volumetric stability; durability; characteristic strengths; environmental impacts; workability; and placement. To address these issues, innovative material combinations of Natural Hydraulic Lime (NHL) and Ground Granulated Blast-furnace Slag (GGBS) are suggested as promising alternatives to traditional cements. Recent changes to BS8500 have allowed for further ternary systems that use GGBS and calcium carbonate thereby giving increased importance to both as ingredients. Combining NHL5 and GGBS can enhance the sustainability of concrete by reducing CO2e, improving resistance to chemical attacks, and maintain overall structural integrity, whilst preserving desirable workability and aesthetic qualities. This research shows the peak mass replacement range of NHL and GGBS in the binary cementitious system at conventional concrete mix ratios, building upon and filling some of the empirical and data gaps. GGBS was used because of its low CO2e, direct cementitious qualities, and to reduce industrial waste. The NHL5 content in concrete was replaced at 10% and 20% increments up to 100% GGBS in concrete to assess the physical properties and mechanical performance. Analysis of compressive and flexural strengths at varying curing ages of 7,14, 28, 91 and 180 days, were conducted for the standard mix ratios of 1:1:2, 1:1:3, 2:1(1:2) and 2:1(2:1). Two curing conditions were examined at 91 days of curing, being submerged in water and in ambient conditions. Increased mechanical performance was produced using a 1:1:3 mix ratio, with the optimum replacement values occurring between 40-60% replacement for all ratios, with the optimal replacement value at 48% and carbon intensity point at 32%, representing the peak mass replacement range and points thus providing evidence and supporting the assertions made from thermodynamic models. The highest compressive and flexural strengths achieved at 31MPa and 2.0MPa by 1:1:3, water cured 40/60, and air cured 60/40, NHL/GGBS samples respectively, being significant gains in strength when compared to either the pure NHL or GGBS binder control concrete samples.

Water has a crucial place in the advent of humankind the flourishing of mega population centres, and is an essential source of food, water transportation, and irrigation. The anthropogenic activities in taming the natural water streams to the optimum benefit of human beings disturb natural flood plains, ecology and habitat. The channelisation of streams and hydromodifications in dams, barrages or reservoirs result in climatic variations locally/ regionally and impact transborder stream flow. Researchers have been endeavouring to restore the flood plains to their natural conditions. Still, huge hydromodifications and the development of megacities right in the flood plains or adjacent to the streams have resulted in irreversible disturbances to the natural lay of ground/ landscape. Therefore, to avoid flooding disasters, further structural interventions are undertaken to augment the natural flood prevention methods using advanced materials like cement concrete, steel, and polymers rather than increasing the emissions of greenhouse gases. Considering the strategic necessity of engineering structures as an integrated catchment level solution to augment the natural methods, the researchers/ engineers are now focussing on the use of sustainable, eco-friendly materials and demountable/ hydraulic structures to minimise the carbon footprints of hydromodifications and to decrease the obstruction to the natural flow of streams by using the flood prevention structures/ gates/ walls/ reservoirs only in case of disastrous flooding and otherwise keeping them unemployed during normal stream discharges. This study has been used to review sustainable flood management using natural and structural techniques in the Wharf River catchment in the UK, reviewing the existing research/ flood management schemes giving the pictorial coverage. The study suggests that natural flood management techniques have restricted application parameters and must be augmented by engineering structures to achieve effective flood management against heavy flooding. Low CO2 embodied greener infrastructure structural materials containing supplementary cementitious materials (SCMs) can be a beneficial option for an environmentally friendly flood management strategy.

Fly ash-based geopolymer concrete (FAGC) is a sustainable alternative to Portland cement concrete, offering significant reductions in carbon emissions while maintaining sufficient strength. This study proposes a three-stage framework for developing empirical formulae to accurately and interpretably predict FAGC compressive strength. In the first stage, predictive models were developed using linear regression (LR), deep neural network (DNN), and residual neural network (ResNet) approaches. Among these, the ResNet model achieved the highest predictive accuracy and effectively captured the complex nonlinear relationship between mix components, curing conditions, and compressive strength. In the second stage, global sensitivity analysis identified sodium silicate content, curing time, sodium hydroxide molarity, and water content as the most influential variables. Additionally, the interaction between fine aggregate content and curing temperature was found to have a substantial effect on strength development. In the final stage, an empirical formula was developed based on key variables and their interactions, providing a simple yet reliable tool for practical strength prediction with reduced computational requirements. The proposed framework is expected to bridge the gap between machine-learning prediction and applicability to support mix design optimisation and promote the wider adoption of sustainable geopolymer concrete in construction applications.

Solid waste management is a combination of techniques of disposing of, collecting, and recycling solid waste. Effective management of waste is vital for maintaining a sustainable environment. In countries where illegal disposal of waste and pollution are rampant, waste management is a way of dealing with deadly diseases such as cholera and malaria. This study examines the current regulations in Nigeria with the view to identify the main weakness and provide a way for forwarding. Qualitative data was analysed thematically to identify current weaknesses in waste management. It identifies weak rules, lack of public education, limited funding, and inadequate enforcement policies as the main factors that curtail waste management. The study proposes increased participation of the private sector, public education, and increased funding as a way forward to enhancing the countries waste management systems. The findings, recommendations and framework of this journal can be extended to all Africa in general and developing countries.

The world generates over 2 billion tonnes of waste annually, whilst at the same time increasing traffic on roads and climate change are causing pavements to deteriorate faster than their nominal design life. A lot of the waste generated could find useful applications as replacements for current construction materials, whose extraction and use cause serious environmental issues. It was in view of the above dilemma that a novel optimisation technique has been developed to increase the amount of waste that could be recycled into pavement materials. The project has developed novel and sustainable asphalt pavement materials from optimising substitutions involving recycled aggregates (Reclaimed Asphalt Pavement, Incinerator Bottom Ash, polyethylene terephthalate) and recycled binders (Low Density Polyethylene (LDPE), Polyethylene Terephthalate (PET), and Polypropylene). These substitutes have been shown, through rigorous laboratory testing to successfully replace less-sustainable constituents whilst at the same time increasing pavement performance to deal with increasing loads from traffic and the environment. The results show that binary substitutions consisting of reclaimed asphalt pavement, municipal incinerator bottom ash and polyethylene fine aggregate substitution respectively in combination with natural aggregates are optimal at percentages of 35%, 40% and 6%. The optimal ternary aggregate with reclaimed asphalt pavement, municipal incinerator bottom ash and natural aggregate is one consisting of 20% reclaimed asphalt pavement, 20% municipal incinerator bottom ash and 60 % natural aggregates. This combination also produces an optimal quaternary mixture with the addition of 6% PET fine aggregate substitution. It has also been established when the aggregate systems above are further combined with optimised asphalt binders, further benefits are derived. This work opens up numerous possibilities to increase the amount of recycled materials in asphalt concrete mixtures through systematic incremental optimisation.

Soil is one of the most important materials in construction, however it is often neglected in other construction material textbooks. It is one of the most variable materials to consider as it is naturally occurring. Also, it will be, almost certainly, inconsistent from one site to the next site. The most important elements to consider are: the range of soils, their properties/parameters and what causes variations in these values.

This thesis investigates the use of rice husk ash (RHA) as a sustainable alternative to traditional portland cement in rigid highway pavements. The literature review highlights the significant environmental impact of cement production, the historical development and properties of concrete, and the potential benefits of using RHA, a by-product of rice milling, due to its high pozzolanic activity and availability.The methodology involved preparing various concrete mixes, including control mixes and those with RHA replacements. Detailed tests were conducted to evaluate workability, compressive strength, tensile strength, curing time, and durability. The research adhered to the specifications set out in the Manual of Contract Documents for Highway Works (MCHW) and relevant British Standards. The preparation of materials included ensuring the quality and consistency of aggregates, cement, water, admixtures, and RHA. The concrete samples were tested for workability using slump tests, and mechanical properties were assessed through uniaxial compression and indirect tension tests.Key results indicate that RHA concrete mixes exhibit comparable or superior compressive strength to traditional mixes, with improved tensile strength and enhanced durability against environmental stressors such as freeze-thaw cycles and chloride penetration. The workability and curing times of RHA mixes were also found to be favourable, with RHA improving the mix's overall performance. The study also noted that RHA concrete had a lower heat evolution peak during curing, reducing the risk of thermal cracking.A field trial on the M180 motorway demonstrated the practical applicability of RHA concrete, showing satisfactory performance in real-world conditions. The concrete mix used in the field trial met the target strength requirements and exhibited good workability and durability. The findings suggest that RHA concrete not only meets structural and durability requirements but also significantly reduces the carbon footprint of pavement construction. This research concludes that RHA is a viable and sustainable alternative for use in pavement quality concrete. Recommendations for future work include long-term performance monitoring, economic feasibility studies, optimisation of mix designs, and the development of standards and guidelines to facilitate the adoption of RHA in the construction industry.

This thesis focuses on practices of public awareness and identifies people’s knowledge, attitudes, and behaviour toward solid waste management in Nigeria. An evaluation of the country's common solid waste management practices and the available strategies that could promote sustainable waste management programs were explored. Other purposes of this paper are to highlight the problems related to solid waste management and important issues that must be addressed to eliminate the poor environmental practices in Nigeria and to underpin facts that the primary concern of solid waste management in Nigeria is the lack of enabling legislation or lack of adequate policies, as well as the lack of an environmentally sensitive and unenlightened public culminated in this research. Using a mixed method approach, the study evaluates the factors responsible for poor solid waste management and how effective the waste management implementation policies are, whilst the theoretical framework was used to provide a general overview of the relationship between different elements of human behaviours. The research provided an avenue for testing two theoretical constructs, solid waste and public awareness since they had not been previously tested and was achieved by measuring the degree to which the two variables mediated the relationship between the two constructs and examining the effects of variables on the nature of the relationship between the two constructs are novelty contribution. The findings are that there is a lack of environmental consideration in Nigeria's attitudes and practices towards sustainable waste management. The study concludes that governments at all levels must implement effective strategies, public enlightenment programmes, and campaigns to ensure public awareness of the danger of poor waste management to human health and social developmental activities to enhance the United Nations Development Sustainable Goals. Recommendations are that the government should promulgate, enforce and implement new laws that could promote environmental management compliance in addition to existing laws. Proper environmental management practices should also be embedded into the institutional curriculum, public training, enlightenment, and awareness to promote people’s consciousness of reducing, reusing, and recycling solid waste. This will help in the pathway to attaining the nation's sustainable development goals.

Anthropogenic activities in river catchments and hydromodification in the channel's morphology impact the ecology/ climate, resulting in catastrophic flooding. Structural measures using cement concrete are employed without efficient flood risk assessment, resulting in additional environmental damages as cement concrete is considered the third biggest emitter of CO2 globally (7-10%) after power generation and aviation/ transportation industries. The researchers always endeavoured to dispose of substantial waste exhibiting pozzolanic properties from diverse industrial/ agricultural fields and the construction industry to formulate greener supplementary cementitious composites (SCMs). The incorporation of fibres obtained from the waste materials had been envisaged as an inexpensive solution to overcome the weak tensile/ flexural strength of binders for lesser reinforcement stipulations for mitigation against rupture before the initiation of plastic deformation. As a solution, non-cement alternative, lime-based fibre-reinforced pozzolanic, innovative composites (NALFRIC) (low - medium strength requirements of 10-30 MPa), fibre-reinforced partial cement-based SCMs (medium - high-strength SCMs 50-70 MPa), and novel, alternative fibre reinforced iron-based composites (NAFRIC) (high-strength SCMs 50-70 MPa) were developed in this research project as sustainable, eco-friendly greener materials. NAFRIC contains iron powder, pozzolans, limestone and fibres, which was anticipated to attain a lower CO2 equilibrium as it absorbs CO2 from the environment to produce ferrous carbonate (FeCO3), yielding a rock-like sustainable performance to drying/ setting. The durability study using concentrated sulphate solution of 2.5% Na2SO4 + 2.5% MgSO4 and chemical-mechanical synthesis/ micro-structural studies using advanced XRD/ SEM/ TEM/ EDX testing supported the findings about the developed composites as sustainable/ eco-friendly. These materials demonstrated up to 50% lower embodied CO2 with up to 25% lower cost and are considered suitable for all types of applications/ strength stipulations in the construction industry, especially in megaprojects, marine environments, and water channel stabilisation/ hydromodifications.

The well-known weakness of cement concrete against external/internal sulphate attack and an estimated 7-10% global greenhouse gas emission by the construction industry (mainly contributed by cement manufacturing and supply have encouraged researchers to elucidate the chemical synthesis taking place in the preparation and hydration of cement concrete along with the factors affecting the sustainability of hardened concrete. In this review study, an endeavour has been made to explore the use of Supplementary Cementitious Materials (SCMs) of different hydrocarbon compositions, including organic/ inorganic compounds like pozzolans derived from natural (zeolite/ metakaolin derived from kaolinite), agricultural (rice husk ash, corn cob ash) and industrial fields Pulverised Fly Ash (PFA), Silica Fume (SF) and a renowned cement replacement material, i.e., Ground Granulated Blast Furnace Slag (GGBS),). The partial replacement of 0-30% pozzolans with cement as a binder has been reviewed objectively to achieve economic/ environmental benefits by enhancing strength and durability against dangerous sulphate attacks. The chemo-mechanical synthesis involving SCMs has been explored to understand the formation of additional calcium silicate hydrate C-S-H gel by blending various pozzolans. The research elucidates an improvement in strength up to optimum ratios of 1-15% for different SCMs. However, the strength was observed to reduce beyond a certain % ratio of SCMs blending due to the formation of expansive alkaline silica hydroxide gel, which causes cracking and weak structure. The aviation industry is considered the top emitter of CO2 (3% of total global emissions), however, the construction industry emits 7-10% of global greenhouse gases, which is nearly three times greater. Therefore, the supportive use of up to 90% SCMs can result in a significant reduction of CO2 by the construction industry based on the type/ratio of blending SCMs. Microstructural studies using scanning electron microscopy SEM and X-ray Diffraction (XRD) have also been explored. These microstructural studies have further clarified the development of ettringite in concrete after sulphate attack and the beneficial use of pozzolans to a certain extent to prevent the formation/ propagation of ettringite-specific cracks in the micro/ nano-pores of concrete structures. In general, research has shown that the addition of SCMs in concrete results in an increase in strength and superior resistance to sulphate attack.

Mortar for masonry is important because it provides the bond between masonry units so enabling the composite to behave as a single material. The type of mortar used determines the flexural and compressive strength of the masonry. Currently, most mortars used in construction are cement based. However, due to the heavy energy-intensive processes that are involved in its production the cement industry is responsible for up to 10% of global CO2 emissions; therefore, there are serious environmental implications with the usage and application of cement mortars. A sustainable alternative are lime mortars which have 30% less embodied CO2. Lime mortars confer benefits in comparison to cement based mortars such as accommodating a greater degree of wall movement and improved damp resistance. The main disadvantage with lime mortars is the longer setting time which can take up to 91 days in addition to the low strength. A way to overcome this is to add cement replacements e.g pozzolans or slag. This paper investigates the properties of non-hydraulic (lime putty) lime mortar containing up to 20% ground granulated blastfurnace slag (GGBS). Findings show a minimal amount of GGBS addition of 2% doubles the mortar strength to 2 MPa within 91 days with an eventual strength of over 15 MPa achieved with 20% GGBS. Strengths satisfying minimum requirements for all four mortar designations were achieved with between 2 - 16% GGBS addition, all within 56 days ageing; with designations (i), (ii), (iii) & (iv) strengths being satisfied within 28 days. Therefore, non-hydraulic lime mortars with GGBS offer a more sustainable alternative to cement based mortars without compromising setting time or strength whilst offering improved flexibility and breathability.

Lime is one of the widely used materials in several industries, with an estimated production of 430 million tons worldwide, with the iron, steel and metal industries as the leader, using 250 million tons, followed by the construction industry using around 75 million tons and the chemical industry with 55 million tons usage per annum worldwide. The broadly used types of lime are quick lime CaO (CL90 Q), hydrated lime Ca(OH)2 (CL90 S), hydraulic lime and lime putty. The primary purpose of hydrated lime is to induce alkalinity and use it as filler material to control porosity. Hydrated lime, unlike hydraulic lime, does not exhibit much-cementing properties on mixing with water. Therefore, it requires blending with suitable binders like cement, pozzolans, and bitumen to acquire better binding characteristics. Hydrated lime is widely used in the iron and steel industry as a cheap, sustainable material for converting iron into pig iron and steel and improving the durability of refractories in the blast furnace. The agriculture and food industry also relies heavily on hydrated lime to be used as a purifying flocculating coagulating agent, especially in the sugar industry. The hydrated lime acts as an alkali activator, deodorising and anti-bacterial chemical in treating wastewater/sludge, agricultural fields and environmental protection. The hydrated lime is used to treat wet, marine and cohesive expansive clayey soils as it absorbs moisture and improves engineering properties like compressibility, strength, plasticity, bearing capacity, consistency, sheer strength and shrinkage etc. One of the main usages of hydrated lime in civil engineering applications is in cement- based mortars as a plasticiser. Therefore, the hydrated lime can be recommended for use in diverse industries and multi-purpose roles.

The climatic variations and anthropogenic activities in the river catchments worldwide are causing severe weather events and flooding. The narrowing down of natural floodplains/ channels, land-use changes, deforestation and mushroom urbanisation with unplanned infrastructure development are aggravating causes of severe storms and floods, especially in developing countries. Hydrological studies, flood modelling and statistical flood frequency analysis are considered imperative to assess the hazards/ risks of flooding and their mitigation measures. Estimating predicted storms/ floods for different return periods can give a reasonable idea about the frequency of storm events. This study analysed the Swat river basin to determine the predicted return periods with expected storm/ flood in its catchment and Swat river. The weather and rainfall in the Swat river basin remain unpredictable. Historically, it has seen peak precipitation of 150mm – 274mm and a super flood of 10050 m3/sec in 2010, more than its 200 years return period. Flood frequency and statistical analysis using Log Pearson 3 (LP3), Generalized Extreme Value (GEV) and Gumbel Maximum (Gumb-Max) on Easy Fit software and Log Pearson 3 equations have predicted weather instability in the Swat basin with the prediction of super flood like 2010 happening in 40 years return period. Construction of Swat expressway on elevated embankment will disturb the natural drainage pattern and likely result in inundation in flood plains due to inadequate capacity of cross drainage structures to withstand the spontaneous flash flooding. However, these have been designed on 100 years return period. However, probability density and hazard functions show a lesser probability of any mega hazard; therefore, cross drainage structures and crisscrossing channels in the river catchments may be planned on a minimum 100 years return period as an economic/ reasonable safe limit. Still, additional structural/ non-structural measures should augment these for efficient flood-fighting like plantation and maintenance of drainage structures, construction of small dams/ reservoirs for swift water management in case of a flash flood and placement of rescue/ relief resources at accessible points as per flood zoning.

The characteristic global warming potential of ordinary Portland cement (OPC) makes it a huge challenge for researchers to weigh its enormous use with potentially feasible engineering properties versus the environmental impacts. The formulation of sustainable, economical, and greener supplementary cementitious materials (SCMs) is an ongoing phenomenon, attracting the large-scale attention of industry/ academia. The formulation of ferrock by David Stone with low embodied energy, lower consumption of natural resources and minimal global warming potential has paved the way for the use of novel material comprising iron powder, pozzolans (pulverised fly ash (PFA) and metakaolin (MK) and lime exhibiting at par performance with OPC. However, a gap has been identified in its formulation, raising a further research question on how it will perform if PFA and MK are replaced by ground granulated blast furnace slag (GGBS) or other pozzolans like silica fume (SF) etc., with different mix ratios. Therefore, an endeavour has been made in this study to identify the engineering properties with sustainable use of modified binary and ternary pozzolans/ GGBS in place of 20% PFA in conventional ferrock. The conventional ferrock contains 8% MK and 20% PFA (as binary pozzolans), 60% iron powder, 12% lime and 2% oxalic acid (set 1). An effort has been made to formulate the different mixes of 10,20,30,40 and 50% by keeping 60% iron powder, 12% lime, 8% MK and 2% oxalic acid constant but replacing 20% PFA with 20% GGBS (set 2), with 10%PFA+10%GGBS (set 3) and with 10%PFA+10%SF (set 4). A target compressive strength of C32/40 or M40 concrete was selected for this study to achieve and compare results with the control mix (0% ferrock) and conventional ferrock during the experimental investigation of modified novel materials. 10-20% ratios of modified mixes exhibited the best performance and achieved the threshold strength of 60 MPa of high-strength cement concrete. Maximum compressive strength of 65 MPa was achieved by the 10% mix of set 2 (20% GGBS), followed by 20% mix ratios of set 3 (10%PFA+10%GGBS) and set 4 (10%PFA+10%SF), achieving 64 MPa. Whereas the 10% mix of the conventional ferrock (set1) reached 63 MPa strength, and the control mix with no ferrock gained 57 MPa strength at 56 days of curing. Overall, an increase of 2-13% compressive strength was observed with10- 30% mixes of all the SCMs; however, a decrease of 3-27% was observed with 40-50% use of SCMs. The use of iron powder increased the ductility of ferrock-based SCMs mixes and exhibited more flexural strength. Set 3 performed the best in exhibiting up to 5.8 MPa flexural strength, followed by set 4, set 2 and lastly, set 1 of conventional ferrock. 20% and 30% mix ratios exhibited flexural strength of more than 5% MPa, better than 10% and 40/ 50% mixes. The study supports the use of 10-20% ferrock-based SCMs for high-strength concrete and 10-50% for concrete mixes with a target strength of C32/40 or M40 to decrease the CO2 footprints of the construction industry significantly.

Water is essential in the disposition and growth of living species, especially in the maintenance and survival of human life. History divulges that all the civilisations, countries and big cities were established along the main river courses/ water channels merely because of the importance of water in human life. The increased world population has increased the depletion of this natural resource. Anthropogenic activities pollute water resources by throwing physical, chemical, biological and industrial waste in these streams. The division of regions into states and countries and different ruling bodies in different areas of the world have purported the issues of maintaining control of water bodies and their rights of use within the river basins based on the trans-borders flow/ catchment areas and multinational utilisation. European Union, since its inception, has been issuing different directives regarding the environment, pollution, water usage, ecology and hydrology. In 2000, a detailed directive named “Water Framework Directive (EU WFD 2000)” was formulated by the European Union encompassing significant aspects of all previous directives with the direct responsibility of each member state to arrange implementation of this directive by incorporating this directive in legislation and establishment of independent bodies/ agencies for its implementation in true letter and spirit. Three years were given to incorporate the water framework directive as law. Then further specified periods were given to implement it in a phased manner from 2003 to 2015. Though a tremendous change in attitude towards maintaining the water quality, partial implementation of EU WFD in member states has been achieved, unfortunately; still, the target is too far away, especially in tackling the heavily modified water bodies despite multi-billion investments by public and private sectors. An endeavour has been made to critically review/ evaluate the challenges in implementing the water framework directive and the efforts of member states to overcome these challenges. The scope of this paper is to review some of the available literature on the subject in the form of books, European Union directives, conventions/ conference minutes/ proceedings/ documents, assessment reports, documents of environmental agencies of member states and different presentations followed by a suitable conclusion as per own understanding from literature and assessment by different sources.

The researchers pioneered incorporating waste materials exhibiting pozzolanic properties and waste fibers from diverse industrial/agricultural fields into the construction industry to formulate enhanced, greener supplementary cementitious composites (SCMs). This research focused objectively on the formulation/evaluation of low-CO2-embodied greener construction materials known as “novel, alternative, fiber-reinforced iron-based binary/ternary pozzolanic composites (abbreviated as NAFRIC)”. The composites incorporated iron powder (Fe), metakaolin (MK), pulverized fly ash (PFA), ground granulated blastfurnace slag (GGBS), palm ash, silica fume, and limestone, which are anticipated to absorb CO2 while producing siderite (ferrous carbonate FeCO3). All the NAFRIC mixes formulated in this study demonstrated up to 4–13% improvement in compressive strength and 70–130% in flexural strength with an enhanced rupture modulus/post-crack ductility. The ternary pozzolanic iron-based fiber-reinforced concrete (FRC) composites containing 8% MK + 10% PFA + 10% GGBS and steel/polypropylene/polyethylene terephthalate (PET) fibers performed the best with attaining up to 70 MPa compressive and up to 8.9 MPa flexural strengths. The sulfate testing evaluated the durability of NAFRIC SCMs formulated in a 1:2:3 ratio better than cement concrete control mix with a 1:1:3 ratio. NAFRIC specimens demonstrated minimal surface deterioration/elongation and negligible/no strength reduction after 270 days of concentrated sulfate attack. The microstructural analysis using X-ray diffraction/fluorescence, scanning electron microscopy/energy-dispersive analysis with X-ray spectroscopy supported the strength and durability parameters by showing minimal/no ettringite formation and increased calcium silicate hydrates gel formation due to the use of FeCO3 and pozzolans. The study demonstrated the sustainable use of these better-performing NAFRIC SCMs with 10–12% reduced embodied CO2 as eco-friendly high-strength SCMs with enhanced engineering/environmental benefits.

The construction industry is a key CO2 contributor. Contemporary research focuses on formulating cement replacement composites; however, less attention is deliberated to formulating fine/coarse aggregate replacement composites. The waste from different fields contributes enormously to adverse environmental effects, thus necessitating reuse/recycling. The demolition/reconstruction of old buildings/infrastructure is adding further to the waste contribution by the construction industry. The total quantum of fine/coarse aggregate in the construction industry is estimated to be around 20 billion tons, contributing around a billion tons of CO2. Therefore, even partial replacement of virgin sand/coarse aggregates with various waste materials like glass, rubber, plastic, tyres, recycled concrete and others will economise the cost of manufacturing the concrete with reduced CO2 footprints as eco-friendly materials. This study conducted a comparative analysis for investigation of the characteristic compressive and split tensile strength of concrete composites with partial replacement of virgin sand/coarse aggregate by 10-30% of Crushed Glass (CG), Crumb Rubber (CR), Recycled PET Bottles (RPB), Recycled Concrete Aggregate (RCA) and 5-10% of Shredded Tyres (ST). Generally, all the composites demonstrated par/ better strength with the control mix, achieving the target strength of C55/67 concrete. The composites with CG, RPB and RCA exhibited an improvement in compressive strength, attaining more than 70 MPa (high-performance concrete strength) and up to 10% improvement in split tensile, attaining 4.3 MPa. CR and 5-10% ST exhibited a slight decrease in compressive strengths. All the composites formulated in this study explicate their diverse uses for multipurpose infrastructural applications in the construction industry as improved, economical, eco-friendly waste absorbent composites.

The developed countries have been doing extraordinary marvels in science, technology and construction with a desire to tame nature coherently. This domination desire has negatively/ irreversibly impacted the environment. However, after generating enormous challenges to nature through uncontrolled developments, the developed countries started endeavouring to save the environment from the devastating impacts of construction projects at the end of the 20th century by incorporating the environmental impact assessment (EIA). EIA is the process of identifying, evaluating, and mitigating development projects' damaging environmental and social effects. In the last 25 years, EIA has developed into a mature system and is an effective tool for assessing, minimising and mitigating severe impacts of development projects on the environment. EIA is only an assessment tool to ascertain the damaging effects of projects on the environment and alternative proposals for their mitigation; however, the final decision rests with political authorities who may consider the EIA report or turn it down in the name of better interests of society/country. Unfortunately, EIA has not proved to be a fully effective process as the developed countries are still undertaking unobstructed/ unopposed mega development projects best conforming to their better interests, and developing countries are still far behind in the apprehension of the necessity of EIA. However, with the UN, USA and EU efforts, more than 120 countries have pledged to exercise EIA to assess development projects before their commencement. In this study, an endeavour has been made to review the necessity/ objectives of EIA, its historical evolutionary process, internationally recognised legal obligations, the stages of the EIA process based on the nature of projects, constraints/ pros and cons of the implementation of EIA process and efficacy of EIA as an intended tool to save the environment from the hazards of mega projects duly supported by three case studies of international projects in USA, Sweden and Pakistan.

Cost overrun and delay are very frequent phenomenon and are generally associated with nearly all projects in the world especially in developing countries. Generally, 71 percent of projects suffer from cost/time overrun in the world with an average cost overrun of 43%. In this study, 25 factors causing cost and time overrun were considered. The ranking of 25 factors causing cost overrun and delay in construction projects made on the basis of mean value of impact which was determined from 65 project data file and 65 executive’s opinion on structured instrument, giving equal weightage to both the values. The factor of “Inconsistent Cash Flow” was the most significant factor with impact value of 7.78 in severe category and “Weather Severity” was the least significant factor with impact value of 3.40 in moderate category. In this study, 65 projects of different departments executed by Frontier Works Organization (FWO) were considered which include 48 completed and 17 running projects. FWO is one of the biggest construction organizations of Pakistan with a financial worth of Rs.36 billions and annual turnover of Rs.22 Billions working all over Pakistan and abroad. Out of 65 selected projects, 38 were roads projects, 12 infrastructure and development projects (private sector) and 15 projects of Government Departments (Railway, WAPDA, Structures, Irrigation/ Power, Airports &Telecomm). Out of 65 projects, only 7 projects were completed within budget thus showing that 90 % projects are suffering from cost variation including 74% projects over running cost and 15% projects under running cost due to scope reduction. Only 2 projects were completed on planned schedule thus showing that 97% of projects were suffering from delay. Overall average cost overrun was 28.27% with an average delay of 2.1 years per project. The highest cost overrun has been observed in projects of Government Departments i.e. 37.59% and highest delay per projects was observed in roads projects i.e. 2.3 years per project. The public/private organizations, regulatory bodies, financing institutions and government should control the financing, planning, management and technical aspects of projects to minimize the cost/time overrun.

The use of lime as a binder and natural fibers as reinforcements have been in use since ancient human history. However, ordinary Portland cement and concrete have substituted these comparatively cheaper eco-friendlier materials due to their quick setting and strength parameters since the 19th century. However, their large-scale impact on the environment due to greenhouse gases emission has encouraged further research to develop novel composite materials comprising natural fibers like coconut coir and lime as partial cement substitute. In this review study, contemporary research studies conducted by different researchers were explored and has found this field quite encouraging and progressive for modern trends in construction materials. Coir is a material with great potential due to its high strength and ductility comparable to steel; the use of lime or saline treated coir in cement by 1% as optimum quantity and in some cases up to 2% quantity, enhanced the compressive, tensile and flexural strengths up to 5%-20%. Ductility and flexibility of concrete improved with more energy absorption capacity. However, more use of coir did not improve engineering properties of concrete rather deteriorated after 2% use by weight of cement. 1% to 2% coir use in expensive marine soil augmented by 5% use of lime revealed considerable increase in engineering properties of soil especially increase of compressive strength by 1.5 times, increase of compaction factor and plasticity and reduction in shrinkage and liquid limit thus supporting a fruitful use of coir and lime mixture in its properties enhancement. Coir being a natural fiber has a limitation of lesser degradation life so needs to be treated with some suitable natural coating material to enhance its life from 3 to 20 years and needs to be cleaned properly by soaking in lime or saline water to remove lignin, pith, cellulose and silicate crystals. The overall use of coir and lime as substituent of cement binders is highly recommended though further research is required to maximize usage for this economical and eco-friendly material.

Mortar for masonry is important because it provides the linkage between masonry units so enabling the composite to behave as a single material. The type of mortar used determines the flexural and compressive strength of the masonry. Nowadays most mortars used in construction are cement based. However, due to the heavy energy-intensive processes that are involved in its production the cement industry is responsible for up to 10% of global CO2 emissions; therefore, there are serious environmental implications with the usage and application of cement mortars. A sustainable alternative are lime mortars which have 30% less embodied CO2. Lime mortars confer benefits in comparison to cement based mortars such as accommodating a greater degree of wall movement and improved damp resistance. The main disadvantage with lime mortars is the longer setting time which can take up to 91 days in addition to the low strength. A way to overcome this is to add cement replacements e.g pozzolans. This paper investigates the properties of non-hydraulic (lime putty) lime mortar containing metakaolin (MK). Findings show a minimal amount of MK addition of 2% increases the mortar strength to 2 MPa within 28 days with an eventual strength of over 17 MPa achieved with 10% MK. Strengths satisfying minimum requirements for all four mortar designations were achieved with between 2-8% MK addition, mostly within 28 days ageing. Therefore, non-hydraulic lime mortars with MK offer a more sustainable alternative to cement based mortars without compromising setting time or strength whilst offering improved flexibility and breathability.

The rivers and water streams are considered as a source of fresh drinking water for the human being on earth. The main source of water entering to these reservoirs is surface run off, snow melting and underground water. The water at the river’s mouth is generally in the form of small streams which are considered clean but as they flow down the catchment, pollutants and nutrients start to enter in larger amounts due to anthropogenic activities and advanced land use by human beings. As per inspection of chief inspector “Drinking Water Inspectorate (DWI)” in 2016, out of more than 4600 water bodies and 3700 rivers in England, only one sixth could get “good” status and two third could get “moderate” status as per European union standards. This is though a good achievement in Europe but alarming also, as all rivers are required to have achieved specified “good” standards by 2021 (extended to 2027 for some categories). This phenomenon is pronouncing more complications in drinking water reservoirs or compensatory reservoirs from where water is taken out to utility companies and treated for domestic water supply incurring an enormous cost on its treatment before human consumption. The clean water standards can be achieved only if a strict control is implemented on entry of pollutants/ nutrients from surface run off using thorough catchment scale sensitive strategies. UK has been implementing strict measures under Environment Agency (EA), Department for Environment, Food and Rural Affairs (DEFRA) and other organizations like “Natural England”, “River Trust” and water utility/ supply companies to achieve desired standards of water quality in rivers by managing the whole catchment as per European union water framework directive (EU WFD) 2000.The catchment sensitive farming and nitrate vulnerable zones policies were started in 1992 and has been in full practice by implementing different stewardship schemes and fertilizers control measures in farmlands and arable lands. Ingbirchworth reservoir and Scout Dyke compensatory reservoir have been under catchment sensitive stewardship schemes to control quantities of nutrients especially nitrates and other pollutants since 2006 to maintain good quality water reservoirs for drinking and compensation to Don river. A partial success has been achieved in controlling the values of nitrates, phosphates, and suspended solids to enter from catchment farmlands by controlling the use of slurry/ fertilizers and implementation of good farming techniques. However, temporal and special variations show a variable result of presence of nitrates, phosphates and suspended solids at different streams in different times, more than specified limits of 11.3mg/L, 0.1mg/L and 25mg/L respectively. This requires more holistic efforts to control the bad practices in farming in adjacent farm/arable lands and improvements in stewardship schemes for catchment sensitive farming in Ingbirchworth areas.

In the field of sustainable concrete practices, this review paper focuses on the concerns of the high percentage of embodied carbon dioxide present in the earth’s atmosphere by addressing the pivotal impact concrete has on this. Cement being a main ingredient in concrete has a great share in the amount of carbon dioxide embodied into the world. The substantial environmental impact of cement production on a regular basis underscores the urgency to explore alternatives and substitutions. Previous studies by scientists and engineers have successfully demonstrated the viability of partial cement replacement by percentages in concrete by enhancing its properties and reducing the environmental impact. This review paper will focus on the idea of potentially complete cement replacement in concrete. This potential idea is build based on the foundation laid by previous engineering researchers and scientists that have explored and delved into the study of potential and possible cement replacements. By recognizing that cement is a major and a main component in concrete and is a major sustainable challenge to overcome, the analysis of previous results and research will be explored based on the feasibility and implication of eliminating cement entirely from the concrete mix. Numerous tests performed previously has been conducted and recorded on partial cement replacements have shown promising results indicating the suitability of cement-free concrete for low to medium structural applications. This review goes beyond traditional studied that gradually replace cement, instead it highlights a paradigm shift towards complete replacement. A critical evaluation of existing research and findings with the aim of contributing to a more sustainable future for concrete applications. By conducting a critical evaluation and an inclusion and exclusion method to identify the gaps in the analysis, this review paper will not only highlight the successful partial replacements of cement but will also identify the gaps in literature, providing a guiding future investigation and prompting a more environmentally friendly and a conscious approach towards the concrete production in the engineering world. Being an informative resource for both industry experts and newcomers.

Concrete production’s reliance on traditional Portland cement is a significant contributor to global construction and development. Concrete production’s reliance on traditional Portland cement is a significant contributor up to 10% global CO2 emissions, prompting a need for sustainable alternatives. This study explores the use of geopolymer binders, composed of industrial and agricultural by-products ground granulated blast furnace slag (GGBS) and metakaolin (MK), as a low-carbon alternative to conventional cement. An experimental investigation has been conducted to assess the workability and compressive strength of various cement free concrete mixes, tested at intervals of 5, 7, 28, and 91 days. The study also examined the impact of different curing methods (air and water curing) and activator-to-binder (a/b) ratios on the concrete’s mechanical properties. The findings revealed that both the binder composition and curing method significantly influence the compressive strength, with certain mixes demonstrating superior long-term performance, particularly those with optimized a/b ratios and higher GGBS content. These insights underscore the potential of geopolymer binders as a sustainable alternative to Portland cement, offering a viable path to reducing the carbon footprint of concrete production while maintaining structural integrity.

Durability of concrete is defined as its ability to resist any form of deterioration, allowing it to retain its original form and quality after it has been exposed to the environment of its intended use. Sulfate attack causes concrete to lose its compressive strength through the decomposition of the products of hydration of cement. Pozzolanic reactions from Supplementary Cementitious Materials (SCMs) help in resisting the sodium sulfate (Na2SO4) attack. This work investigated the potential use of Anthill Soil (AHS) to improve the performance of concrete in sulfate aggressive environments. An AHS replacement of 30% (per cent) by the weight of cement was used to make concrete test bars and cubes. The 0% replacement also referred to as the control was used as the point of reference from which all performances were measured. The specimens were immersed in 5% Na2SO4, 5% magnesium sulfate (MgSO4), and 5% mixed solution of Na2SO4 and MgSO4. Elongation measurements were taken over a period of 9 months, whereas compressive strength tests, which were used to work out the Strength Deterioration Factors (SDFs) and visual observations for surface deterioration were carried out at 9 months. From the results, AHS specimens that were immersed in the Na2SO4, MgSO4 and mixed Na2SO4 and MgSO4 solutions performed poorly in elongation compared with the control specimens, but had lower SDFs in the Na2SO4 and mixed solutions of Na2SO4 and MgSO4. The surface deterioration of AHS specimens in the MgSO4 solution was worse than that of the control specimens but was similar to that of the control in the mixed sulfate solution of Na2SO4 and MgSO4. The SDF results highlight the potential of using AHS with an advantage in Na2SO4 and mixed Na2SO4 and MgSO4 environments.

Researchers have been working on formulating Fibre Reinforced Concrete (FRC) composites that are economical, eco-friendly, and waste absorbent. Incorporating agricultural/ industrial waste into the construction industry as fibre-reinforced composites is a novel research field that can recycle and convert waste into valuable supplementary materials. In this study, concrete composites with fibres of coconut coir (COF), wheat straw (WSF), and shredded fibres from waste plastic bottles (PETF) were evaluated and compared against the established use of polypropylene fibres (PPF) and steel fibres (SF). The study’s objectives were set to attain the strength of 32-40MPa (C32/40 European grade) for using these waste fibres as alternatives in FRC. A concrete mix ratio of 1:2:3 with 1-2% waste fibres (COF & PETF), 1-2% PPFC and 10% & 17% steel fibres were used to produce cubes, cylinders, and prisms for testing on 7 and 28 days for evaluation of compressive, split tensile and flexural strengths. Generally, all FRC mixes with 1% fibre dosage exhibited an increase of compressive strength by 9-44% at 28 days of curing. All fibre composites gave characteristic compressive strength of 40-60MPa. The split tensile strength of all- fibre composites was improved up to 48% with 1-2% fibres. The flexural strength of all-fibre composites improved by 11-42% with 1% fibre and 10% steel fibre but increased fibre’s quantity to 2% and steel fibre to 17% reduced the flexural strength suggesting that fibre content should not exceed more than 2% of cement weight in composites. Shredded fibres of PET plastic bottles outperformed the established micro/macro PPF as PETF exhibited better flexural strength than PPF with both 1 and 2% dosages. The natural fibres of coir/ wheat straw gave better/at par flexural strength (7.3MPa) compared to steel fibres (6.9MPa). In conclusion, it is suggested that the optimum quantity of 1-2% of these novel alternative fibres after necessary treatment is feasible for the for the formulation of environmentally friendly fibre concrete composite with enhanced mechanical properties.

A fundamental issue with the active ingredient of concrete, Portland cement, is its energy-intensive manufacturing process, which has led to the cement industry emitting up to 10% of global CO2 levels. To facilitate the reduction in the embodied CO entirely replaced volumetrically with Hydrated Lime (HL) and ground granulated blast furnace slag (GGBS or SL). GGBS was used to replace hydrated lime content in 10% increments up to 100% GGBS. Analysis of compressive and flexural strength and density testing was performed on samples to investigate the mechanical and physical properties at 7, 28 and 91-day curing ages, whilst flexural testing was conducted at 91 days curing age. Four standard mix ratios, 1:1:3, 1:2:3, 1:1:2 and 2:1 was made for comparison. Two curing conditions were tested at 91-day curing age, these being air-cured and water curing. Results have shown the optimum mix ratio to be 1:1:2 for all mixes. The optimum mix being HL 1:1:2 SL80%, water cured exceeding 25MPa. Throughout the different ratios, it can be concluded that the optimum replacement of GGBS lies between 80-90%; it can also be noted that 100% GGBS content sees a significant drop in compressive and flexural strength, indicating the presence of hydrated lime to be a catalyst for strength gain.

Mortar for masonry is important because it provides the linkage between masonry units so enabling the composite to behave as a single material. The type of mortar used determines the flexural and compressive strength of the masonry, so in this paper, a range of mortars are examined. These include traditional designation (iii) (1 cement : 1 lime : 6 sand), designation (iv) (1 cement : 1 lime : 9 sand) mortars as defined in BS 5628: Part 1[ref], and two thin layer mortars. The conventional mortars were formed using both CEM I 42.5N or CEM I 32.5N PC (Portland Cement) to BS EN 197; Part 1 in order to ascertain the difference these two cements have on the properties of mortar. The thin layer mortars show remarkably high compressive strength.

In this study, the characteristic flexural strength of low density aircrete wallettes incorporating both conventional and thin layer mortar is verified. The wallettes were tested in accordance with British and European standards. The flexural strength of aircrete wallettes was derived from the strength of small specimens tested to destruction under four-point loading. The strengths of the wallettes are high with impressive repeatability with the maximum strength being reached for thin layer wallettes within 7 days curing time. In general the strengths of both conventional mortar and thin layer mortar wallettes compare favourably to values reported in the standards.

The aims of the study are to identify an effective and versatile fungal strain for bioengineering mycelium composites. The influence of temperature and four different growth media on mycelium growth of two white rot fungi, Pleurotus ostreatus (Winter Oyster) and Ganoderma lucidum (Reishi) were investigated in laboratory conditions. The results of the experiment indicated that potato dextrose agar (PDA) was the most suitable growth media for mycelium growth of fungal strains, P. ostreatus and G. lucidum. However, P. ostreatus was the better performing strain, with highest mean mycelium growth of 23.28cm, compared to G. lucidum at 9.03cm on PDA after 12 days of inoculation. Potato dextrose agar (23.28cm) and potato dextrose agar supplemented with yeast extract (14.74cm) were more favorable for mean radial mycelium growth of P. ostreatus, followed by sabouraud dextrose agar (9.85cm) and iron sulphite agar (8.35cm). The fungal strain, P. ostreatus obtained improved mycelium morphology on potato dextrose agar (PDA) supplemented with yeast extract and obtained cottony textured mycelium with good density and growth on potato dextrose agar (PDA) and sabouraud dextrose agar (SDA). Iron sulphite agar (ISA) was least favourable growth media for mean radial mycelium growth and mycelium morphology. Fungal strain, G. lucidum only mycelium growth was obtained on potato dextrose agar (PDA) as a result of this study, was the least favourable fungal strain studied. Optimal temperature for mycelium growth for both fungal strains, P. ostreatus and G. lucidum was obtained at 22 °C.