The Effects of Water/Cement Ratio and Cement Dosage Variables on the Performance of Shotcrete: Compressive Strength and Drying Shrinkage Perspective

Abstract

Shotcrete is a construction material that is applied by spraying under high pressure, and there are many factors that affect its properties. In this study, the effect of cement dosage and water-to-cement ratio on the compressive strength and drying shrinkage performance of shotcrete was investigated. For this purpose, shotcrete specimens were produced using three different water-to-cement ratios (0.40, 0.45, 0.50) and three different cement dosages (400, 450, 500). The unit weight, ultrasonic pulse velocity (UPV), compressive strength, splitting tensile strength, and drying shrinkage performance of the produced specimens were examined. As a result of the experimental studies, an increase in cement dosage resulted in an increase in unit weight values, with the amount of increase ranging from approximately 1% to 3%. When the UPV value was examined, an increase in cement dosage resulted in an increase in UPV values, with an increase of approximately 1% to 5%. An increase in cement dosage also resulted in an increase in compressive strength and splitting tensile strength values, with the increase ranging from approximately 12%-16%, 5%-9%, and 10%-12% for the 500, 450, and 400 dosage groups, respectively. The drying shrinkage values increased with increasing cement dosage, the highest shrinkage values occurred in the groups with 0.50 water/cement ratio and 500 dosage, and it was observed that 85-95% of the total shrinkage of the shotcrete specimens was completed within the first 1 hour. Furthermore, the data obtained can be used to determine the optimum water/cement ratio and cement dosage for the construction of shotcrete.