Experimental Study Of Drying Shrinkage Of Concrete Brick

At present, the masonry structure are still the main structural form which small and medium-sized city in the construction of multi-storey building housing take. In recent years, with the promoted of the China's policy that "the clay brick is forbidden in constructing buildings", the application of concrete perforated bricks are developed rapidly in the constructing buildings. The development of concrete peforated brick not only is in line with the needs of new wall materials of the communityand improvement of the ecological environment, but also has low price with very good economic benefits,which has been recognized by the market. However, the bond strength between concrete peforated bricks and mortars are lower than that of the fired bricks, the shrinkage deformation of concrete perforated brick masonry are also larger. At present, these properties of the new wallboard materials, such as concrete peforated bricks, are recognized not enough, we still used in the design and construction methods of clay brick, the dry shrinkage cracks problem of concrete perforated brick masonry have become more and more. Then, the introduction and application of concrete perforated brick are limited. Therefore, it is important to study the shrinkage reasons of concrete perforated bricks and control its shrinkage cracks.Based on the test results for the dry shrinkage deformation of concrete peforated brick masonry with different mortar strength, different sizes and different restricting conditions cured in the standard environment and the natural environment within 108 days, the main factors affecting the dry shrinkage deformatiaon such as the mortar strength, the ambient temperature, the relative humidity, the curing ages, the height and the restricting condition are discussed and analyzed. The formulas which estimated the free dry shrinkage deformation of concrete perforated brick masonry without restricting are suggested. The formulas which estimated the dry shrinkage deformation of concrete perforated brick masonry with restricting are suggested. Besides, the formulas match well with the experimental datas, and this may be as a reference for controlling the dry shrinkage cracks of concrete perforated brick masonry.The research subject is one of the new wallboard materials special foundation items in Henan province.