The effect of expansive agent and cooling rate in the performance of expanded glass lightweight aggregate as an internal curing agent

Abstract

Lightweight aggregates can provide internal curing (IC) in concrete and reduce autogenous shrinkage and related cracking, but they produce a reduction in concrete strength. Expanded glass lightweight aggre-gates (EG-LWAs) allow for design and engineer their properties to develop better IC agents. Expansive agent silicon carbide (SiC) content and post-expansion cooling rates were systematically varied in order to develop a competitive IC agent with a controlled reduction in concrete strength. Slow cooling produced the EG-LWA with the highest intrinsic strength, but with limited water delivery capacity. Rapid cooling produced EG-LWA with lower intrinsic strength, but with the highest water delivery capacity; they reduced autogenous shrinkage at 28 days by 34% and 50% for specimens with 2.5% and 5.5% of SiC,respectively. The results of this research indicated the possibility to maximize the capacity of EG-LWA as IC agent through an optimum SiC dosage and cooling treatment.