Research On Crack Mechanism Of New Lightweight-Wall Panel

New materials, which are light, saving energy and multifunctional, have been used in present building in the world. But domestic production technology and construction are still in an initial level. The most major reason is that cracks occur in joint surface between the lightweight wall panel and the solid structure. As a result how to solve the problem has been a key technology in lightweight wall panel construction process. Up to now, Few is reported on the systemic study about the problem shown in relevant internal media.The article primarily emphasizes the study about the problem, that dry shrinkage and cold shrinkage lead to the wall panel cracking from the structure on joint place, especially when the Siberia cold current floating towards south in winter. Mechanism and prevention-and-cure solution of cracking are researched systematically in this article. On the one hand, combine the fruit of domestic study and overseas research, the author analysis the cause and have a synthesis computations. On the other hand, the research is based on systemic experiments and tests, which "P-UAC" lightweight compound-wall panel is used for. Combined with actual building construction practice, some prototype experiments are performed and the data is collected.Refer to the measuring result of elastic modulus of light-boned concrete material which is provided by China building-material academe, and the result of international standard test method. The author finds out the big difference of dynamical character between 2 types of different materials(the lightweight wall panel and the high-intensity concrete) is one of the most major factors leading to cracking on joint place. The stress-strain relationship of the 2 types of material is uncompatible. A big difference of the shrinkage ratio between the 2 types of material occurs. In this study two kinds of experiments are performed, one is the research of the disciplinarian of dry shrinkage on lightweight wall panel, the other is the test of dry shrinkage in simulate environment. These conclusions are drawn. The distortion caused by dry and humidity of the lightweight wall material keeps the balance with the surrounding mass dryness fraction and humidity. So the change of surrounding humidity is the primary factor leading the lightweight wall material dry shrinkage. In the environment when relative humidity Xi>70%, the lightweight wall material is assembled with those high building structures, dry-shrinkage strain e,,,, which is resulted in the low temperature and high mass dry fraction in winter, causes crack.Based on the analysis of cracking mechanism three techniques to control the cracks are propose.1. Adding a layer of coating on lightweight wall panel surface to insulate the effects of environmental humidity, and this is called the obturating technique, which will reduce the happening of cracking.2. The core of lightweight wall panel adopts compensating-shrinkage concrete. The measure will compensate or completely kill the cracking of joint utilizing the mild expand after hardening. So the technique controls the happening of cracking.3. To improve the anti-crack intensity, the grouting in whole is introduced. The measure changes the restrict states of lightweight-compound wall panel and the structure, preventing the happening of cracking.