An investigation of fly ash and lightweight sand on high-performance mortar

A high-performance mortar with high compressive strength and high flow is often used for repairing cracks, filling in the gap of a splice sleeve, and joints of precast concrete structures. In this study, a high-performance mortar with a compressive strength greater than 80 MPa was designed based on traditional sand, cement, water, and industrial wastes such as fly ash from thermal power plants. The mortar mixtures were studied based on practical investigation. The traditional sand was then replaced by lightweight sand from black lava stone to investigate the internal curing effect. The mortar which included 29.7%, 19.8%, and 5.5% of the unit volume for traditional sand, lightweight sand, and fly ash, respectively, satisfied the strength requirement. A 1% superplasticizer by weight of cement was adequate to create a flowable mortar. A suitable amount of lightweight sand in a mortar mixture could contribute to the compressive strength of the high performance mortar through internal curing