Sustainable stabilisation of the Lower Oxford Clay by non-traditional binder

Wastepaper Sludge Ash (WSA), an industrial by-product from the paper industry can possibly be utilised to modify certain engineering properties of soils for specific uses to conserve non-renewable natural resources. Sulphate-bearing clays (Lower Oxford Clay, LOC) stabilised with various stabilisers on the basis of WSA (such as WSA–lime, WSA–Portland cement and WSA–ground granulated blastfurnace slag) under controlled laboratory conditions. The stabilisers reduced the plasticity index (PI) and maximum dry density (MDD), increased the optimum moisture content (OMC) of LOC. The compressive strength of these stabilised clays was comparable to the clay stabilised by the traditional stabiliser lime (CaO) and was better when WSA was combined with ground granulated blastfurnace slag (GGBS) and with Portland cement (PC). This system also performs better in terms of linear expansion. The results therefore indicate environmental, economic, as well as technological benefits in utilising WSA as soil stabiliser.