Recycling of municipal incinerator fly-ash slag and semiconductor waste sludge as admixtures in cement mortar

We proposed to tackle the problem of fly-ash pollution from municipal solid waste incineration as well as sludge from chemical–mechanical polishing, by partial substitution of cement in mortar. The optimal modified cement mortar determined by the Taguchi method showed unexpected strengthening effects starting after 4 days of curing and gradually reached a maximum strengthening at 90 days of curing up to 139% of that of ordinary cement mortar. The polluting leachants from the modified cement mortar were barely detectable in toxicity characteristic leaching process tests. The mechanism of the precipitous strengthening effect is preliminarily attributed to nanoparticle activation and enriched hydration.