Mortar putty crack reason analysis and processing method

Guide language: crack, crack of cement mortar, putty is a problem with the universality of common. After years of research and practice, the author thinks that the crack of plastering mortar, wall putty, the cause of cracks mainly from two aspects of 'internal' and 'external'. Reason analysis: 'internal cause' aspect 'internal cause' mainly because some of plastering mortar, putty products of dry shrinkage, dry shrinkage is fast, produce large internal stress cracking mortar structure and cause damage, crack performance generally show irregular crack shape, is often said that the turtle crack, mainly some manufacturers for raw materials properties, functions and full understanding of the technology principle, the raw materials used does not conform to the requirements, the formula is not science, leading to product quality is not stable, crack resistance is poor, appeared shortly after construction of large area crack, empty drum, fall off. Cement mortar strength, crack effect all have important relationship with water, the hydration of cement and condense sclerosis is a gradual process, continuity, hydration, first after the condensation, condensation sclerosis of the outcome, depends on the condition of hydration, hydration, the more fully, the better water conservation, water conservation, the longer the intensity of the higher, the smaller shrinkage, crack effect is better; The hydration of cement and condense sclerosis speed is influenced by environmental temperature is obvious, namely high environmental temperature, hydration and hardening speed is fast, the environment temperature is low, cement hydration and hardening of the condensation of velocity is slowly. All early, early, early strength of cement mortar, because water is not good, since the maintenance ability is poor, can produce too much too fast, contraction force, prone to large area cracks. Early in the research and practice, dry and hard, early late early strength of cement mortar strength and stability, crack resistance are better than dry hard, late, late late cement mortar to poor, which is the cement as inorganic the particularity of the water rigid gelled material. Processing method: 1, the tortoise cracks, mainly related to the cement, no matter what type of cement, dry shrinkage problems, from the test, sulphur aluminate cement, white cement, cement varieties of late strength and stability, good crack resistance is less than that of ordinary Portland cement, is mainly the product itself contractility, rapid drying shrinkage, shrinkage force strong, easy to produce turtle crack. Ordinary Portland cement in the application of common construction projects in our country, and have decades of history, it is a very good performance, through research and test, as long as hydration, water conservation and sufficient condition is better, a few years later, even after ten years of their strength will be improved. At present, polymer mortar, cement, be bored with child still is given priority to with ordinary Portland cement, the use of models to 32. 5 r or 42. 5 r, putty in the polymer mortar, cement products in the formula ratio must grasp well. 2, 'external', 'external', is mainly caused by construction technology, the foundation and the natural environment. Usually, building design and construction is not scientific and unreasonable, foundation settlement, deviation, construction before one-time wipe is too thick, the construction of basement has a significant crack, earthquake, after the big wind pressure produced by the stress, the construction of continuous high temperature dry weather and so on, will cause the generation of cracks, cracks, with crack is commonly, the performance of the shape of horizontal type, vertical type or irregular type. 3, a crack in cement mortar and cement base putty crack another characteristic is that: no matter how thick or more thin, the crack fracture have been split from the surface to the end, this also is building the fundamental cause of leakage. Crack crack size, large crack fracture can be easily see, small crack crack not necessarily to the naked eye can see, but as long as to pour water on the metope of dry, micro crack fracture can see clearly. 4, if appear crack, crack, basically have no reliable materials and technology can be fully restored, the result can give a building decoration, decoration, waterproof engineering and maintenance work in the future cause great difficulties, this is because the wall cracks, as the external environment condition, Foundation settlement, such as earthquake and large temperature difference and dry humidity change at the same time, the aperture size, shape, are also constantly change subsequently, namely gap size will change when the winter cold and summer heat, is in the same season rainy day and sunny day, aperture size will also change, all in all, 24 hours a day are changing. It is also a crack, crack in the roof, metope, underground waterproof engineering and maintenance practice, which is the most headache thing, often is fixed, after less than a year or even several months, began to leak. As long as no crack fracture, in general is not going to happen the leakage of the buildings, people who understand cement pool, knew that as long as you don't have any crack crack and seepage of cement pool is not going to happen.