Research on the effect of lithological characteristics of manufactured sand on the strength of mortar

The excessive extraction and utilization of river sand may lead to the destruction of river ecosystems. The use of manufactured sand as a substitute for river sand can effectively avoid the aforementioned issues. However, there are significant differences in the strength of mortar or concrete prepared using different types of sand. The influence law for lithological characteristics of three types of manufactured sand on mortar strength was investigated in depth. The core causes of strength variation influenced by different parent rocks were explained based on various macroscopic and microscopic test methods. The results of the flexural and compression tests showed that the different parent rock types would have a significant effect on the mortar strength, where molybdenum tailing sand had the largest increase in 28d strength of 17%. In addition, as decreasing the interfacial transition zone (ITZ) volume fraction and increasing the elastic and hardness moduli of ITZ, the mortar strength gradually increased. This study showed that using manufactured sand as a substitute for river sand reduced extraction and improved mortar strength while maintaining workability. Molybdenum tailings sand performed the best, which was significant for sustainable construction and environmental protection.