Physical & mechanical properties of pervious concrete incorporating municipal solid waste incineration bottom ash

Abstract

Municipal solid waste incineration bottom ash (BA) as a cementitious substitute in pervious concrete constitutes a viable strategy for waste recycling and carbon emission mitigation. Nonetheless, the resultant alterations in the cementitious matrix composition and the inter-aggregate macro-porous structure induced by BA incorporation still need to be explored, limiting a thorough understanding of the mechanical behavior and permeability. Macroscopic tests were employed to investigate the impact of BA and compaction densities on the physical and mechanical properties. The effects of BA on the hydration products were analyzed using X-ray diffraction (XRD) and thermogravimetric analysis (TG) methods. The results reveal that at a density of 2190 kg/m³, BA has minimal effect on the interconnected porosity and permeability. However, as the density increases, a higher BA substitution ratio leads to a narrowed pore distribution and a significant reduction in permeability. Furthermore, a power-function relationship exists between the compressive strength and dynamic modulus of elasticity. At a 15 % substitution ratio, a slight decrease in hydration products was observed, resulting in a minor reduction in compressive strength. Concurrently, a linear relationship was established between the proportion of tiny pores (less than two mm2) and the relative compressive strength. Considering both permeability and mechanical performance, pervious concrete with a density of 2310 kg/m3 and containing no more than 10 % BA meets the requirements of the CJJ/T135-2009 standard. These findings provide a scientific basis for the mix design of pervious concrete incorporating BA.