Effect of incinerator bottom ash properties on mechanical and pore size of blended cement mortars

Abstract

This paper presents an experimental investigation on the effect of incinerator bottom ash (IBA) fineness and the cooled process of molten IBA on fresh mortar properties and compressive strength, shrinkage, alkali-aggregate reaction, and pore size distribution of hardened mortars. IBA with two finenesses, an original IBA, and a pulverizing incinerator bottom ash (PIBA) powder, with maximum particle size of 4.75 and 0.074mm respectively were used to partially replace sand and Portland cement at 0%, 10%, 20%, 30%, and 40% by weight. The pozzolanic activity characteristics of powder were obtained from melting the above PIBA in an electric-furnace at 1450°C for 1h and chilled by quenching in water (WIBA) and air (AIBA). Results indicate that incinerator bottom ash caused a reduction in compressive strength, unit weight, and flowability values when used as a replacement for sand and cement. However, IBA can be processed by melting to regain reactive pozzolanic activity, which may be used to partially replace cement. The incorporation of WIBA and AIBA decreased total capillary pore porosity of the mortars compared to that with ordinary PIBA. The AIBA possesses lower hydraulic properties of WIBA. Improved properties of WIBA and AIBA result from the dense structure achieved by the filling effect of the pozzolanic product. Pozzolanic strength activity index (PSAI) results and scanning electron microscope (SEM) observations confirm these findings. Therefore, WIBA and AIBA can act as either a cementitious material or as an inert filler in cement-based composites.