Study On The Physical And Mechanical Performance Of Back Covered Porous Brick And Its Masonry

Back covered porous brick has been developed in the late period of 1990's, and is produced by semi-dry-pressing method. It has such many advantages as high production efficiency, energy saving, high density, beautiful appearance, high strength, easy bricklaying, and can save 1/3 masonry mortar compared with solid brick. But it is possible to reduce the shear' resistance and aseismatic ability when back covered porous brick builds the brickwork because it has not the "pin" formed by the masonry mortar leaked into the hole.Supported by the Energy Efficiency and Walling Materials Reforming Office of Baoji city, we studied and valued the technical performance of back covered porous brick and its masonry comprehensively and objectively from March to December in 2002, so as to offer recommendations to decision makers in the government and the scientific data to designers.The research results indicate that the heat-insulating property of back covered porous brick and its brick wall is better than KP1 porous brick. The compressive strength of the back covered porous brick masonry reaches the Standard level. The elastic modulus of the masonry is equivalent to other porous brick masonry and higher than solid brick masonry.The shearing strength of back covered porous brick masonry is slightly lower than the Standard level. A coefficient of 0.9 can be multiplied to ensure the safety of structures. By and large, the back covered porous brick wall with constructional column and gird beam has the same shearing strength under low circulated load as other porous brick wall, so the shear resistance and aseismatic capability can be calculated by theStandard method. The experiment indicates that the back covered porous brick wall has good energy absorbing as well as deforming capability, and it can satisfy the requirement of aseismatic structures.It is necessary to point out that the covered end thickness of back covered porous brick is increasing as the machine wearing, and it results in the decreasing pore space ratio. The brick-maldng factory should manage strictly ensuring the product to reach the standard level of their corporation.