Using glass sand as an alternative for quartz sand in UHPC

Ultra-high-performance concrete (UHPC) is characterized by a dense microstructure that yields ultra-high strength and durability properties. Quartz sand (QS) with maximum particle sizes of 600 μm represents the coarse particles in (UHPC). The QS with optimum grading curve is obtained from crushing coarse sand or rocks, however this is a time-consuming, costly, and polluting process. This paper reports on a study to determine the possibility of producing and using glass sand (GS) for partial or total replacement of QS in UHPC. The results show that GS with a mean particle size (d50) of 275 µm could be recommended as an optimal PSD to replace QS particles. The results demonstrate that compressive strength values of about 196 and 182 MPa after two days of hot curing can be achieved when replacing 50% and 100% of QS with GS, respectively, compared to 204 MPa for reference UHPC containing 100% QS. Incorporating higher replacement rates of GS was shown to produce UHPC of accepted flowability and dense microstructure that mitigated the aggregate alkali–silica reaction.