Supplementary cementitious materials such as silica fume and fly ash are often used in high performance concrete. Both materials increase the modulus of elasticity as well as the compressive strength of the concrete. However, the modulus of elasticity increases at a lower rate than the compressive strength. Furthermore, high performance concrete containing supplementary cementitious materials has a lower gain in modulus of elasticity over time compared to high performance concrete that does not contain any mineral admixtures. Overall, the effect of fly ash and silica fume on the modulus of elasticity for high performance concrete is negligible when compared to other parameters (coarse aggregate properties, etc.).