12 - Self-compacting concrete adopting recycled aggregates

Abstract

Recycled self-compacting concrete is a kind of self-compacting concrete prepared by recycled aggregate which partially or completely replaces natural aggregate. This chapter introduces the material composition of recycled self-compacting concrete. This chapter describes the basic characteristics of recycled aggregate, the modification methods adopted and the mix design of recycled self-compacting concrete, and introduces the effects of recycled aggregate on the working performance, mechanical properties and durability properties (resistance to chloride penetration, carbonation, and shrinkage) of self-compacting concrete. By integrating and refining the existing literature, it is found that recycled aggregate has a negative impact on the macroscopic properties of self-compacting concrete, and is closely related to the particle characteristics, water absorption, coarse or fine, and substitution rate of recycled aggregate. The increase of substitution rate will lead to the decrease of flowability, strength, elastic modulus, resistance to chloride penetration, and carbonation of concrete. The multi-angle and high water absorption of the particles are the main reasons for the reduction of working performance, and the strength will be slightly improved by using a small amount of recycled fine aggregate. Recycled aggregate with higher water absorption will produce internal curing effect in concrete, and then reduce the shrinkage deformation of recycled self-compacting concrete.