The document studies the impact of adding crumb rubber to concrete as a replacement for fine aggregates. Concrete cubes were created with 0%, 5%, 10%, 15%, and 20% replacement of fine aggregates with crumb rubber. Compressive strength and Young's modulus were tested on the cubes at 7, 14, and 28 days. Results showed that compressive strength and Young's modulus decreased as rubber content increased. The 10% replacement mixture at 28 days provided sufficient strength while reducing waste rubber. In conclusion, crumb rubber can replace up to 10% of fine aggregates to utilize waste tires while providing concrete with some compressive strength and toughness.