Incinerator bottom ash: engineering and environmental properties as a cement bound paving material

This paper reports a laboratory study investigating the use of incinerator bottom ash (IBA) as cement bound material (CBM) for use in sub-base and roadbase layers. Engineering properties associated with its use are determined and practical limits on IBA content discussed. It was found that IBA could be practically used in proportions of 40% or more by mass for all CBM categories defined in the UK Highway specification. However, the use of IBA as aggregate in CBM required higher cement contents to achieve the same compressive and tensile strength. Tests carried out to confirm that leachable constituents were bound in the mixture and raised no environmental concern were carried out by comparing the results of tank leach tests with a one-dimensional model. It was observed that despite the tests and models being designed to maximise release of species, that leachates were well within typical regulatory drinking limits.