The object of the research is the use of glass powder and ultrafine glass powder as sustainable alternatives to natural sand in M25-grade concrete, addressing the environmental and resource challenges caused by sand depletion in Jordan. Method. The study examines the effects of replacing fine aggregate with glass powder (10% to 20%) on concrete's compressive strength, using the water absorption method. The concrete mixes were designed following ACI 211.1 guidelines, with materials hand-mixed and each component precisely weighed. The mix was placed in cubic molds, compacted, and cured in water for 28 days. A total of 24 specimens were prepared and tested for compressive strength after 28 days using a universal testing machine C040PN. Results. Incorporating 10% glass powder as a cement replacement optimizes the mechanical performance of concrete, achieving a 28-day compressive strength of 61.98 MPa—10.83% of the control mix strength (55.92 MPa). This mix also demonstrates an ultrasonic pulse velocity of 5.51 km/s, a slump of 60 mm, and a modulus of elasticity of 37 GPa. These results confirm that using 10% glass powder enhances or maintains key structural properties while promoting the sustainable reuse of waste glass—offering a viable, eco-friendly solution for the construction industry in Jordan without compromising performance.