Study On Properties For Sulfate Attacktion Of Hybrid Fiber Concrete

The failures of durability of concrete structures induced by environment are mainly caused by reinforcement corrosion and corrosion in concrete. The corrosion of concrete is divided into chemical corrosion, freeze-thaw damage and alkali-aggregate reaction, and the sulfate attack in chemical corrosion is the most complicated and the most harmful kind of environmental erosion. After sulfate attack the concrete showed swelling, cracking, corrosion, peeling and strength decrease in macro performance, etc., affect the durability of structures, even more serious, the structure will be damaged and collapsed, and causing casualties and economic losses. As a quite promising and emerging branch in composite materials, there are two or more fibers doped into the hybrid fiber concrete, can effectively improve the internal pore structure of concrete, improve the balance of three-dimensional distribution of fibers and coordination of fibers and aggregates from different levels, so that learn from each other, resulting in a composite effect, improving crack resistance toughened performance. So how about the sulfate resistance of hybrid fiber concrete?Through using a method of combining the theoretical analysis with the experimental study, On the basis of in-depth analysis of the mechanism of sulfate attack on concrete and the enhancing of the properties of fiber concrete, using hybrid fiber concrete which is mixing the basalt fibers and the polypropylene fibers carried sulfate attack rapid tests. Using test to simulate wet and dry circulation which is closer to the actual conditions, according to the features of sulfate attack of concrete, using research method which is combined macro with micro, the test of macro mainly including observations of apparent phenomena, quality changes, the relative dynamic elastic modulus changes, the strength changes (compressive and splitting tensile strength) in different erosion ages, the test content of micro mainly including the sulfate ion concentration in different depths at different erosion ages, the porosity of hybrid fiber concrete. Initially established a micro-macro-damage model of hybrid fiber concrete.The results showed that:after sulfate attacked the compressive strength, the splitting tensile strength, the quality changes, the relative dynamic elastic modulus and the same age and depth of erosion sulfate ion concentration and other performance indicators of hybrid fiber concrete are better than ordinary concrete.The series of seminars of the theory and experimental research of hybrid fiber concrete have theoretical significance and application value for improving the sulfate resistance of hybrid fiber concrete.