| Leakage has been a major problem that plagued the quality of building works. While the presence of a variety of drawbacks of traditional building waterproof materials which can not meet the durability requirements of the buildings, the cementitious capillary crystalline waterproofing can not only make up for the defects of a variety of traditional materials, but it is also a persistent waterproof material with excellent performance.The cementitious capillary crystalline waterproofing was prepared on the basis of the inspection and study of related literature and patents, and combined with research and analysis of the parent material of foreign product, a range of possible active components of waterproof coatings were selected and combined into different masterbatch formulations. According to the impermeability experiments of the waterproof formula and the analysis of experimental results*two sets better basic active component of the formula were selected and named the waterproof coating type Ⅰ and type Ⅱ. Type Ⅰ coating formulations was optimized by orthogonal design experiments, and also a series of single factor were investigated such as the content of component A and component B, the ratio of gray and sand, the dose of the material and the interactions of components A、D and E, and ultimately the optimization of the parameters and conditions for type Ⅰ coatings were got. Meanwhile the DPS was used to regressionally predict and the predictive value was reliable. Also the type Ⅱ coatings were optimized by uniform design.The experimental results show that the optimum process parameters and conditions of type Ⅰ formulations were list as follows:the content of component A was4%, the content of component B was3.0%, the content of component C was1.5%, the content of component D was0.5%, the content of component E was1.5%, the ratio of gray and sand was2.0and the dose of coating in experiment was1.5kg/m2and the first pressure was1.0Mpa and the second pressure was1.1Mpa. The optimum process parameters and conditions of type Ⅱ formulations were as follows:the content of soluble complexing agent M was1.06%, the content of complexation precipitant N was0.57%, the content of crystallization expanders O was4.7%, the content of the calcium compensation agent P was1.36%and the content of additives E was0.24%.According to the requirements of the related national standard, the performance of type I waterproof coating that prepared under the optimal conditions was tested, and the results show that:the result of Stability test was3.75mm, the initial setting time was200min while the final setting time was850min, anti-foldstrength of7d and28d were seperatedly5.6Mpa and6.4Mpa, the compressive strength of7d and28d were respectively14.44Mpa and19.61Mpa, the welcoming water impermeability pressure were1.0Mpa(28d) and1.1Mpa(56d), the dorsal surface of the water impermeability pressure were0.9Mpa (28d) and1.0Mpa(56d), these indicators were all in line with the requirements of national standard GB18445-2001.The morphology of mortar matrix with coating was observed by SEM in order to further study the action mechanism of such waterproof coating, and the results showed that a large number of needle-like or radial crystallization as well as some of the gel substances were found in matrix with type I waterproof coating which were inseparable with the infiltration of the active substance in the coatings. They could grow in the gap of the substrate from the outside and gradually plug the gap, which greatly reduced the connectivity of the pores in the concrete matrix and increase the density. The penetration depth of type I waterproof coating was initially identified experimentally10mm. Initially reason the mechanism of impermeability was the dual role of crystallization and complexation. |
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