Preparation And Performance Research On Cementitions Capillary Crystalline Waterproofing Agent

Cementitious capillary crystalline waterproofing agents, an admixture of organic and inorganic chemistry substances, can enter into the inner interstice of concrete through the seeping channel or the normal capillaries in concrete with the effect of water, where they react with the unhydrated cement particles and a compact hydration crystal comes into being, which results in blocking the inter-spaces, capillaries and interstices to achieve the waterproof goals. It differs from the traditional waterproofing agent: for the traditional waterproofing agent, it is extremely effective in the preliminary period, but its performances will gradually degenerates as the time goes. Meanwhile, the self-repairing property obtained in crystalline waterproofing agent will induce the waterproofing performances'increase with time. The unique waterproof performance of cementitious capillary crystalline waterproofing agents is a great reformation in concrete waterproofing capability.The main content of the thesis is the preparation of cementitious capillary crystalline waterproofing agents and the research and test in its waterproof performances. Through investigating the overseas cementitious capillary crystalline waterproofing agent products, the development of waterproofing agents is carried out on the basis of a detailed analysis of the effecting mechanisms of cementitious capillary crystalline waterproofing agents. Series of analysis have come to a conclusion that the development of cementitious capillary crystalline waterproofing agents should follow a complex technical routine: waterproofing mechanism theoretical analysis→selection of reactive ingredients→orthogonal experiment→optimized processing of single component→performance test→technology summary.The first is the selection of reactive ingredients. An effective selection of reactive ingredient is the key of cementitious capillary crystalline waterproofing agents'development and foundation of the entire research process. After research three kinds of reactive ingredients have finally been determined, which are LA,MD and NE. Firstly, with a method of orthogonal design, an initial mixing proportion is ascertained by testing the first and the second osmotic pressure of the samples with different amount of reactive ingredient. Secondly, the single component optimized processing is carried on to successfully develop the cementitious capillary crystalline waterproofing agents,named LG waterproofing agents. According to the national standard JC474-1999 "Water-proof Agent of Concrete and Mortar"and GB18445-2001"Cementitions Capillary Crystalline Waterproofing Materials", the performance of LG waterproofing agents is tested. The results has indicated that 225% osmotic pressure ratio is obtained in LG waterproofing agents and other performance indexes in national standard are also eligible.The second infiltration resistant experiment has suggested that the infiltration resistant pressure of the sample with waterproofing agent increases by 242% in contrast with additive absent sample, which illustrates that the active substances in waterproofing agent could infiltrate with water's infiltration in the results of crystallization and promotion of further cement hydration, blocking the infiltrating channels, repairing cracks and finally improving the waterproofing properties.The micro-analysis through SEM and X-ray diffraction has been carried on to the eligible samples and its waterproofing mechanism is also discussed, the results of which has shown that the gel of C-S-H in cement paste with waterproofing agent increases obviously and the amount of Ca(OH)2 decreases greatly, resulting in a more compact structure in contrast with the comparing samples. All these microcosmic features would be helpful to improve the concrete impermeability. On the basis of theses micro-analysis and related references, the waterproofing mechanism is further discussed.