Design and performance optimization of alkali-activated waste coal bottom ash/slag porous concrete

When alkali-activated slag material is used in porous concrete, it has the problems of short setting time and poor operability. In this paper, the effect of coal bottom ash content on the rheological properties, the mechanical properties, porosity, permeability coefficient, and PFT of AACS-PC of the paste was investigated. The results showed that the fluidity and porosity of the paste with a water-solid ratio of 0.35 were positively correlated with the coal bottom ash content, but negatively correlated with the PFT. When the content of coal bottom ash was 20 wt% and the waterglass modulus was 1.4, the compressive strength of AACS-PC can reach 22.1Mpa and the water permeability coefficient of AACS-PC was 2.9 mm/s. Both the compressive strength and water permeability coefficient could meet the requirements of the standard of ASTM and JIS A. The addition of CBA can effectively improve the operability of alkali -activated materials in the preparation of porous concrete.