The drying shrinkage response of recycled-waste-glass-powder-and calcium-carbonate-based ultrahigh-performance concrete

Abstract

The present investigation evaluates the impact of the partial substitution of cement and microsilica (MS) by mineral admixtures such as calcium carbonate and milled glass powders on the drying shrinkage of ultra-high-performance concrete (UHPC) and ultra-high performance fiber reinforced concrete (UHPFRC). Two dosages with partial substitution of cement and MS were used in addition to another without any substitution as a reference. UHPFRC samples were obtained by adding a 2% (vol.) of steel micro-fiber to these three UHPC dosages. Incorporating calcium carbonate and recycled glass into concrete enhanced rheological properties, thereby decreasing the need for chemical admixtures and increasing cost-effectiveness. The findings demonstrated that the partial substitution of cement and MS reduced the drying shrinkage of both UHPC and UHPFRC with respect to the reference dosage. It was also observed that the reinforcement with micro-fibers, and the narrowing of the dosages of cement and MS, reduced the drying shrinkage up to 40% compared with the reference UHPC. The shrinkage of traditional UHPC concrete, after 2% straight steel fibers, reduced by 10.8, 18.1, 12.1, and 12.2% at 5, 15, 20, and 25 days, respectively. Nevertheless, by incorporating this volume of fibers into the calcium carbonate and glass powder mix, a considerable reduction (40.4, 28.3, 25.0, and 18.1%) was achieved at the same ages.