Effect of composition on performance of ground glass pozzolan

Primary factors affecting the performance of ground glass used as a pozzolan in portland cement concrete include chemical composition, particle size distribution, and replacement level. Eighteen different waste glass streams from across the United States were analyzed for composition and ground to a consistent size distribution. The compressive strength of mortar cubes made with 20 and 30% glass replacement by mass was measured over 6 months. The flexural capacity of conventional reinforced concrete beams was measured with 0, 10, 20, and 30% soda-lime glass replacement. Compressive strength variation was observed between the different types of glasses tested; however, only a subtle correlation between elemental chemical composition and compressive strength was detected. Few mixtures containing glass surpassed the control mixture (0% glass) compressive strength, and most mixtures containing 20% glass reached higher compressive strengths than those with 30%. The beams with 30% replacement had similar flexural capacity compared to the control mixture.