Mitigating inclusion-induced shrinkage cracking in cementitious composites by incorporating recycled concrete fines

Abstract Recent studies on utilization of recycled concrete have demonstrated that usually discarded finest fractions can be incorporated into cementitious composites without scarifying their structural performance. It has been shown that these fines can increase the resistance of a cementitious matrix to tensile stresses and reduce shrinkage, and that these effects can be boosted by addition of mineral admixtures. Such findings led us to a consideration that incorporating recycled concrete fines into a concrete mix could possibly mitigate aggregate-induced shrinkage cracking. Here, this hypothesis was put under scrutiny in a comprehensive experimental-numerical study, confirming that blending Portland cement with recycled concrete fines can mitigate inclusion-induced shrinkage cracking, especially when combined with fly ash. The results of coupled hygro-mechanical modeling indicate that incorporating recycled concrete fines leads not only to a decrease of shrinkage but also increases fracture energy and thus has a major impact on the reduction of micro-cracks between inclusions.