Crack Genetic Analysis Of Concrete Small-Sized Hollow Block Construction In Taizhou

Concrete small hollow block which is in favor of environment and saving plantation is a kind of wall material to substitute for clay block. It is not only lighter than brick wall in weight, which profit anti-seismic behavior of masonry wall, but also the speed of construction is quicker, which profit to shorten construction periods. With the development of new masonry materials reform and architecture environment conception, masonry structure will progress rapid. But the crack is a bad factor which has restricted hollow block to comprehensive application and development of masonry structure.After consulting many literature and datum and referring to the production about crack of wall, the paper summarizes the characteristic, the rule, and discusses deeply the factors on cracks of wall. Based on the research and the academic analysis in material, design and construction of concrete masonry structures wall, the academic foundation and the experiential analysis about the criterion are put forward. At the same time, it improves the application of concrete masonry structures in Tai Zhou district and gives the new method of preventing cracks. The productions include:1. Masonry fracture morphology and research of crack law(1)The form of wall crack has inclined cracks, horizontal crack, vertical cracks and combination of crack, etc. Crack is mainly distributed in the door hole, the junction of wall with framework beam-column and the central of wall. The Survey shows that the wall cracks occur more frequently in the top and bottom. The probability of inclined cracks which appears at the two ends ministry of vertical wall is higher. The cracks often pass through two diagonal of the window, and crack width is larger, there is a positive eight-shaped crack. Some cracks in the lower part of the external walls is a positive eight-shaped, the bottom cracks is wide, the width reduces with upward extension.(2) The formation of cracks in the wall are the result of a number of factors, both the foundation, temperature, shrinkage, and there is negligence on the design, construction or material quality , and other factors.2. Through the shrinkage experiment research of small concrete hollow block wall, it is verified that the early shrinkage deformation of concrete is larger, and the deformation gradually slows down with the passage of time, and the gross contraction trend increases.Tests show that the level shrinkage value of a small concrete block wall in the previous month accounts for the majority of contraction,and gradually decrease with time,fmally,stabiliazed. The vertical contraction of wall is different from the level's,and it shows a steady growth trend in a longer period.3. From the design, construction, production angles for uneven settlement, temperature, shrinkage and other factors on the block wall cracks, the specific crack control measures are given. The beneficial exploration is made for the popularization and application of small concrete hollow block.