Point load test method for prediction strength of sustainable mortar made from blended cement and fly ash

Fly ash (FA) is a by-product of power plants where a number of serious efforts in the field of sustainable building materials have spawned a recycling method in the form of cementitious material containing FA as raw material, including blended cement. The contribution of blended cement to producing sustainable mortar is presented in this study. The FA at a percentage of 10% to 30% by weight of cement is used instead of blended cement in the manufacture of mortar. The results of the point load strength index (PLSI) at the age of 7 days the percentages of FA-0, FA-10, FA-20, and FA-30 were 0.58, 0.46, 0.41, 0.41 N/mm2 and at the age of 28 days were 0.88, 0.85, 0.79, and 0.78 N/mm2 respectively, indicating that the mortar produced with blended cement and FA is carried the point loads well because it has stiffness and adequate robustness. The contrast test with available methods verifies that PLSI offers an alternative to compressive test and it has high accuracy. The point load test method can be used to predict the strength of mortar produced of blended cement and FA.