Use of raw-state bottom ash for aggregates in construction materials

Abstract

The recycling of raw-state bottom ash as it is holds an advantage from an economic and environmental standpoint in that it omits pre-processes such as milling and wetting. Its physical and chemical properties are first characterized for the purpose, and then the use of raw-state bottom ash for aggregates in construction materials is proposed. Preplaced aggregate concrete or dry-mixing concrete scheme can be selectively applied according to the particle size requirement of bottom ash aggregate. Preplaced bottom ash aggregate concrete is produced by placing the bottom ash aggregate in formwork and injecting grout to fill the voids. To ensure the injectability of the grout, relatively large-sized particles, greater than 5 mm, are recommended to be used. In the case of dry-mixing concrete, this is originally designed for manufacturing concrete masonry units and concrete blocks with a low water-to-cement ratio and consolidated zero-slump concrete using a mechanized vibrating mold. The experimental results show that bottom ash aggregate concrete has moderate compressive strength with a low density.