Preparation and Properties of Reactive Powder Concrete with Circulating Fluidized Bed Combustion Fly Ash

Abstract

The mix proportion design of reactive powder concrete(RPC) with circulating fluidized bed combustion(CFBC) fly ash was done through orthogonal design. The effect of curing system on strength and shrinkage property of RPC with CFBC fly ash, and the effect of CFBC fly ash on shrinkage property of RPC were investigated. The results show that RPC which could have flexural strength of 26 MPa and compressive strength of 140 MPa was prepared by using CFBC fly ash, silica fume, superplasticizer, intermediate quartz sand, P·O42.5R and hydrothermal curing treatment; Hydrothermal curing can promote the hydration of RPC with CFBC fly ash and form a relatively dense structure, so its early strength was higher than that of standard curing about 30 MPa, but high temperature made early-formed AFt transform into AFm, so later strength was decreased; Compared to standard curing, Hydrothermal curing promoted the early shrinkage of RPC with CFBC fly ash, reduced the late drying shrinkage, but its overall shrinkage rate was still greater than that of standard curing; The expansibility characteristics of CFBC fly ash can effectively reduce the large self-shrinkage of RPC.