Effect of partially hydrated cementitious materials on early-age shrinkage of ultra-high-performance concrete Available to Purchase

The effect of adding partially hydrated cementitious materials (PHCM) on the early-age shrinkage of ultra-high-performance concrete (UHPC) is investigated. UHPC mixtures incorporating a shrinkage-reducing admixture (SRA) are also tested for comparison. Combined effects of PHCM and SRA in reducing early-age shrinkage are explored. Results indicate a significant improvement in the early-age compressive strength of UHPC mixtures due to PHCM addition. SRA was effective in reducing shrinkage; however, PHCM achieved excellent early-age shrinkage reduction when used alone or combined with SRA. PHCM mitigates undesirable behaviour induced by SRA, including setting time delays and reduction in mechanical properties. The addition of PHCM provides an ecological and economic technique for producing precast and cast-in-place self-restraining shrinkage concrete. Indeed, unused/returned concrete can be recycled in new mixtures to enhance mechanical strength and resistance to shrinkage, and to mitigate set retardation effects.