This paper presents the results of an experimental investigation into the behavior of concrete containing glass sand and tire sand as replacement for natural sand. Various properties: concrete slump, density, compressive, split tensile, flexural strength and water absorption were investigated through single replacement mechanism in which full portion of glass sand and 10%, 20%, 30% of tire sand ... [Show full abstract] replacing fine natural aggregate. Concrete strength observations refer to ASTM C39-10, ASTM C496-04 and ASTM C78 provision. Test results indicate that all replacement mechanisms exhibit undesirable physical behavior and lower concrete strength than conventional concrete. The mortar containing 100% glass sand and higher tire sand content generates higher slump value and lower density. The mortar of R3 batch shows higher slump value, followed by GS100, R2, and R3, while the GS100 batch yields the lowest fresh and hardened density. Specimen R1, R2, R3 and GS100 yield lower compressive strength, split tensile and flexural capacity than the original specimen due to the reduction in bond strength and adhesiveness between particles and cement matrix of modified concrete. There is an insignificant difference in water absorption rate between control concrete and modified concrete. However, lower tire particle content in R1 absorbs less water than specimen R2 and R3 and GS100.