Abstract: The rapid growth of construction technology and the increasing rate of construction have raised concerns about the depletion of natural resources, particularly sand extracted from river beds. The excessive utilization of sand has led to environmental issues and a decline in its availability. Moreover, conventional concrete derived from sand exhibits low tensile strength and limited resistance to cracking.In response, researchers and scientists have been exploring alternative materials that are environmentally friendly, as well as admixtures that enhance concrete properties. Quarry dust has emerged as a promising substitute for sand, possessing similar characteristics to those obtained from stone beds. Additionally, nylon fiber has been identified as a suitable admixture to improve the tensile strength of concrete.This project aims to partially replace sand with quarry dust at varying percentages (10%, 20%, and 30% of sand content) and incorporate 6mm nylon fiber at a dosage of 0.1% by weight of cement. The study focuses on concrete grade M25, subjected to different concentrations (1%, 2%, and 3%) of hydrochloric acid (HCL) during the curing period of 7, 14, and 28 days. The fiber reinforced concrete (FRC) specimens cured in water are compared with those cured in varying concentrations of HCL. The evaluation of concrete properties includes compressive strength tests at 7, 14, and 28 days of curing, as well as a flexural strength test conducted after 28 days of curing.