Application of Municipal Solid Waste Incineration Bottom Ash into Engineered Cementitious Composites

Engineered cementitious composites (ECC) have been manufactured by mixing the treated municipal solid waste incineration (MSWI) bottom ash (BA), ordinary Portland cement, fine silica sand and Polyvinyl Alcohol (PVA) fiber. Characterizations including X-ray fluorescence (XRF) and laser diffraction have been performed on four types of BA powders obtained by combined treatments, and the chemical compositions and particle size distribution of those BA powders are derived. The mechanical properties of BA powders in mortar as cement replacement are tested to determine their reactivity. BA powder with highest reactivity completely replaces the fly ash in ECC, and its contribution to strain hardening of composites is investigated. Results indicate that mortar mixed with BA fines prepared by thermal treatment followed by ball milling has the best mechanical properties. After 28 days of curing, the flexural and compressive strength of this mortar reach 82% and 81% of the reference, respectively. The strength activity index meets the requirement of not less than 70% specified in the Chinese standards. The increase of BA powder not only reduces the first crack strength of ECC but also reduces the ultimate tensile strength of the composites. Fortunately, the strain hardening properties of ECC are improved. In addition, the highest ductile tensile properties are obtained in ECC with BA fines to cement ratio of 2.2. This research provides a strategy in making use of vast resources BA obtained from MSWI.