The Research On Hydration Activity And Mechanism Of Cement Paste With Glass Powder

The development of mineral additives have became most significant compositions in the development of concrete with increasing demand of infrastructure on concrete and exhausting of nature resource.As a new mineral additive of modern concrete,distribution of waste glass is very wide and its quantity is quit plenty in our country,waste glass has potential pozzlanic activity and hardening activity if waste glasses are ground to a certain fineness.Therefore,waste glass has high value of study and application.The previous study focus on macro performance of glass powder concrete and mainly surround particle fineness of glass powder on the ASR effect of composite system.The function?hydrate degree and micro-structure of glass powder in cement-based materials are not well-understand.Relationship and laws between sorts of hydration product?macro-properties and micro-structure of cement concrete with glass powder are revealed by micro-experiment and macro-properties of cement with glass powder.Activity factor was used for evaluating activity of glass powder by certain quantitative calculation and qualitative analysis.Calculated results show that the activity factor of glass powder keeps positive number??0,?1?,this shows contribution of glass powder is lower than that of pure cement in mixture cementitious materials,but glass powder has a positive improving effect on the compressive strength of mixture cementitious materials.The early-age hydration products and paste microstructure of glass powder cement paste were investigated by SEM and XRD,the concept of chemically combined water content and effective method of chemically combined water are proposed to evaluate the effect of glass powder on the composite binder and cement in the early-age hydration.The results show a large amount of hydration products that mainly fiber-form CSH?needle-bar-like ettringite crystal and Ca?OH?2 are formed between 6h to 1d.The hydration products are lapped and interlocked growth to contain some partial not hydration of cement particle,the hydration products and glass powder are bonding to produce system skeleton.The hydration products,the microstructure and mechanical property of cement-based materials with glass powder in different water binder ratio were investigated.The effective method of chemically combined water content and hydration degree are proposed to evaluate the effect of glass powder on the composite binder and cement.The research show that at an early hydration age,physical factors such particle morphology have a more intense influence on the compressive strength development of the composite binder than chemical factors such as hydration degree.Hydration degree of composite binder decreases with increases of the adding rate of glass powder,but it promoted hydration degree of cement on composite binder.The activating effect of different sorts of chemical activator?Na₂SO₄,Na₂CO₃and Na₂SiO₃?and amounts of chemical activator on complex system were studied,the research is to seek the optimum sort and amount of chemical activator.The results show the activating effect of Na₂SO₄ on complex system is higher than that of Na₂CO₃and Na₂SiO₃,4%Na₂SO₄ has greatest effect on the early strength of complex system,the double activator of strong alkali and sulfate of Na₂SO₄ has more obviously effect on complex system,its effect is strong than only alkali activator of Na₂CO₃ and Na₂SiO₃.The NanoSiO₂ was be chosen as the Nano-materials modifiers for complex system.The macro-performance development of complex system with NanoSiO₂ was discussed,early hydration mechanism of NanoSiO₂ on complex system was also discussed.The results show that NanoSiO₂ can consume large amount of Ca?OH?₂ due to its high pozzolanic activity,so that hydration of cement can be accelerated,the slow strength gain of glass powder cementitious materials at early age can be eliminated.NanoSiO₂ can promote early dissolution of cement in system of glass powder cement and enhance alkalinity of complex system,which was in favor of internal energy-rich bond?Si-O,Al-O?broken within glass powder,improving early hydration degree of glass powder.