A study on the macro and micro properties of concrete with LCD glass

This study produced cement mortar samples with a water-to-binder ratio of 0.485 by adding 10%, 20%, 30%, 40% and 50% of waste liquid crystal glass as a replacement for cement, and also used glass sand as a replacement for natural sand (by 0%, 10%, 20%, and 30%), and glass powder of different fineness (3850, 6500 cm2/g) as a replacement for cement, in order to explore the effects of replacing silica-rich waste glass for cement and replacing waste glass for natural sand on the micro-observations and macro-observations of concrete. The results indicated that, by replacing waste liquid crystal glass for the cement in cement mortar, setting time and compressive strength increased as the proportions of substitute increased, while sodium sulfate resistance showed optimal results when 10% was replaced. The 20% glass sand concrete for the three different mix designs retained good slump and slump flow. The compressive strengths of the concrete with glass sand replacement were higher than the design strengths. Moreover, the durability of the concrete with 20% glass sand replacement was better than that of the control group. Surface resistivity for specimens with different amounts of LCD glass sand replacement was also higher than that in the control group for mid- to long-curing ages. Sulfate attack in concrete with different amounts of glass sand replacement caused less weight loss than in the control group. Moderate chloride ion penetration was observed for glass sand concrete. SEM indicated that the structure of cement paste tends to be more compact with lessened porosity and increased interfaced binding affinity when the added glass powder is relatively fine. The result of X-ray Diffract meter analysis indicated that a higher intensity peak of CH and SiO2 appears when the glass sand concentration is relatively high. It is verified that the concrete of normal engineering properties could be achieved by partially replacing waste liquid crystal glass for cement and fine aggregate; the need for natural sand could thereby be reduced, which can contribute to resource recycling and environmental protection.