AbstractThere is a scarcity of natural river sand due to the ban on mining of sand from riverbeds, attributed to environmental and ecological issues. Therefore, there are attempts to use nonorganic solid wastes and industrial by-products as sand substitutes. The paper reports experimental studies on the suitability of processed granulated blast furnace slag (PGBS) as fine aggregate in the mortars used in masonry construction. The physical and chemical characteristics of the PGBS and the properties of mortars made with PGBS, such as workability, compressive strength, water retentivity, drying shrinkage, and elastic properties, were examined. The masonry properties such as compressive strength, flexure bond strength, and stress-strain characteristics were investigated using PGBS- and sand-based mortars. The investigations show that PGBS can be a potential substitute to river sand in the masonry application. The addition of PGBS was beneficial in terms of mortar and masonry characteristics. In the case of lean mortars, the addition of PGBS showed 30% to 45% spike in compressive strength. Thermogravimetry was used to quantify hydration products formed in PGBS-based and river sand–based mortars. The experimental outcomes indicate that (1) the physical and chemical properties of PGBS were similar to those of river sand except that the PGBS may show mild pozzolanic activity and higher water absorption; and (2) the masonry compressive strength increased by ∼22%, and the flexure bond strength nearly doubled when PGBS-based mortars were used.