Mechanochemical activation for transforming bottom ash to reactive supplementary cementitious material

Due to the intrinsic low reactivity of bottom ash (BA), it is not typically used as a direct substitute for ordinary Portland cement (OPC). In this study, a BA-OPC composite was developed by applying small amount of diethanol isopropanolamine (DEIPA) as a chemical admixture. The activation of BA with DEIPA resulted in substantial improvement in the hydration properties of BA-OPC composite. Not only did the OPC hydrations accelerate in the early stage, but the induced pozzolanic reaction was also efficiently activated in the later stage, leading to the more formation of C-S-H. With the use of 0.1% DEIPA, the compressive strength increased by 26.5%, 50.0%, and 23.5% at curing dates of 3, 7, and 28 days, respectively, as compared to the sample without DEIPA. It has been demonstrated that very small amount of DEIPA could be sufficient to increase the chemical compatibility of the BA as supplementary cementitious materials.