New-type Walls' Crack And Leakage Resistance Performance And Engineering Application Research

New-type wall materials are widely used in our country, which have brought much social and economic benefits. But the crack and leakage problems of new-type walls are obviously serious, these problems can bring harmful influence on the building, such as reducing the building function, making the insulation and energy saving invalidation, and losing the service life. In order to extend the using of new-type wall materials, it is extremely urgent to solve the problems of new-type walls'crack and leakage.By combining literature readings and expert consults, Researchs on the engineering application of new-type walls'crack and leakage resistance are systematically and deeply carried out. Researchs are based on many aspects, such as product productions, construction technologies, design and calculations, structural measures, detecting techniques. This thesis includes:Investigation of new-type walls'crack and leakage resistance, Experimental investigation of shrinkage of Concrete perforated brick(CPB) walls at different ages, Numerical simulation of wall-infilled frame's shrinkage, New-type walls'in-field test of surface permeability, Image processing of wall crack etc. Research contents are listed as follows:1) Applications of new-type wall materials in Zhejiang province have been widely investigated, and the sample data are statistical analyzed. Results show that being no detailed guideline of professional management and being imperfection of manage and guarantee system of production occupations cause the original quality defects.2) Numerical simulation analysis of cracks'development by shrinkage effect has been carried out on a practical meeting two-storey and single span wall-infilled structure, using FEM models as whole-type and semi-discrete type. Different column rigidity, opening size, and connection rigidity are described with deformation, stress, and crack development results. Relevant factors are qualitative analysed, including the influences of dead load and problems of deformation and crack by dry shrinkage.3) Masonry structure is analysed using RVE(representative volume element), mainly in elastic stage. Including:RVE simulation of uniaxial tensile and compression strength test, simulation of equivalent elastic constants, element build-up and a whole structure calculation example etc. The feasibility of element expansion from single to whole is validated. 4) Experimental investigations of shrinkage of Concrete perforated brick(CPB) walls at different ages have been carried out. The walls' shrinkage rate and strain variation at early age are concluded. Relationship between instantaneous strain and age is fitted. Experimental results are compared with numerical simulation. Basing on the achievement, engineering treatment measures are proposed.5) Penetration instrument (GWT) and its method are used at in-field testing of agglomeration shale brick and CPB walls' surface permeability. Influence of different materials, locations, test methods to the permeability coefficient are analysed, then the walls' permeability is assessed basing on the results.6) Digital image processing technology for shallow cracks measurement in walls is used. A new method of image segmentation basing on neural network is presented. By this method, cracks images are extracted. The experimental results on project examples show that this method is feasible to gain digital crack information.7) By summarizing above research results and documents readings, a technical guideline has been made for the application of crack and leakage resistance.Above contents correspond to each stage and link the crack-resistance practice. Engineering application research of new-type walls' crack and leakage resistance is complex and progressive, above researches have some stage achievements, which lay a ground for further works.