Experimental investigation on the high-volume fly ash ecological self-compacting concrete

Abstract

As an innovative high-performance concrete, high cementitious material content of Self-compacting concrete (SCC) results in high cost and environmental burden, which limits its application. This paper proposed an innovated mix proportion design method to prepare an ecological self-compacting concrete (Eco-SCC) with more coarse aggregates and higher fly ash (FA) content to reduce the environmental impacts of SCC. The packing ratio (PR) of coarse aggregate, FA content and sand volume ratio of Eco-SCC were optimized, and their influences on the permeability and drying shrinkage ratio were investigated. The optimal mix proportion of Eco-SCC was determined with coarse aggregate PR of 0.6, FA content of 30% and sand volume ratio of 0.48, which has better mechanical properties, lower shrinkage ratio and lower porosity compared to conventional SCC. The high-volume FA Eco-SCC, of which the cement amount was 285 kg/m3 (cementitious materials amount was 475 kg/m3) can reach a higher strength grade with less cementitious materials than conventional SCC, and its 28d and 90d compressive strength are 64 MPa and 74.9 MPa, respectively. Comparing with conventional SCC, the high-volume FA Eco-SCC costs less on raw materials and construction with less environmental impact, which makes it a promising widely used high-performance concrete.