Over the last decade there have been significant advances made with regard to the science and engineering of contaminated sites. There are many different techniques that have been developed to remediate land. The Enhanced Thermal Conduction (ETC) process is one of these techniques. This process uses burners to provide heat by conduction to deplete the levels of contaminates within the soil. The heat causes the contaminants to volatilise, which are then passed through a vapour system to destroy the contaminated gasses. The 'burnt' soil that remains from this process only contain trace contamination, but is still disposed of to landfill. A research project is currently underway to investigate the potential reuse of thermally desorbed soil (TDS) as a novel pozzolanic material.
Summary of findings to date:
- Clear evidence exist that TDS has some form of cementing action (i.e. a pozzolanic activity) as a result of the 100% TDS mortar mix (zero cement) gaining a strength of 1.6 N/mm2 at 90 days.
- TDS can be used in both mortar and concrete mixes up to 25% cement replacement, without a detrimental effect on the compressive strength.
- The benefits in terms of environmental issues for the reuse of TDS as a pozzolan would be twofold; firstly by directly using a waste material as oppose to disposal to landfill; and secondly more indirectly by using less cement, i.e. reducing the amount of CO2 released into the atmosphere during the manufacture of Portland cement.