Experimental Study And Mechanism Analysis On Mechanical Property Of High Performance Concrete With Manufactured Sand After High Temperature

In recent years, our country economy rapid development, the construction quantity increases sharply, concrete as one of the main building materials, their demand also will increase. Originally used in the preparation of concrete is given priority to with natural river sand, but the natural river sand resources are unequally distributed and non-renewable in the short term, the existing natural river sand resources cannot fully meet the needs of the engineering construction. Shanxi Province is located in the middle of the Yellow River basin, terrain is mountain hills, natural river resources are relatively scarce, if from the other cities into natural river sand, the expensive freight will greatly increase the cost of engineering construction. Rock resources in this area for mining processing for sand production mechanism and preparation river sand used in concrete can effectively solve the shortage of resources.As the manufactured sand widely application in commercial concrete, the concrete with manufactured sand buildings subjected to fire high temperature probability is becoming bigger and bigger. The high temperature properties of the normal river sand concrete at home and abroad research has a lot, and the concrete with manufactured sand in recent years to promote the use on buildings, so the study of the high temperature performance have just started.With the support of the national natural science fund project (51278325) and the natural science foundation project of Shanxi Province (2011011024-2), this paper on experimental study and thermal expansion mechanism analysis of mechanical property of high performance concrete with manufactured sand after high temperature, the main contents are as follows:1. Review on the mechanism of sand concrete application and high temperature properties at home and abroad research, the thermal expansion property and mechanism analysis of literature, on the basis of summarizing the predecessors’research results presented in this paper, the research purpose, content and significance. By analyzing the concrete with manufactured sand after high temperature mechanical properties change rule, in order to mechanism sand concrete buildings subjected to high temperature after the fire assessment provide reliable theoretical basis for identification and reinforcement.2. The selection of Shanxi the strength level of the extensive use of C40concrete as the research object, through calculation and test match finally this paper test the mechanism of sand high-performance concrete mixture ratio. Studies have shown that the performance of the concrete under the condition of normal use environment can satisfy practical engineering work required by the performance and mechanical performance.3. The simulation process, building fire was carried out on the mechanism of high performance concrete sand specimens at different temperature to burn through after natural cooling to room temperature mechanical properties (compressive strength, split strength, axial compressive elastic modulus) and test. Research shows that:compared with normal temperature when high performance concrete with manufactured sand after high temperature mechanical properties reduced to some extent, and the higher the temperature, the greater the reduction.4. After the test of coarse aggregate, cement, hardening mechanism of mixed slurry, sand mortar and mechanism of sand concrete five kinds of samples in the process of high temperature and the linear expansion value in the process of cooling to room temperature. Results show that the heating process, a mixture of cement and hardened slurry samples with the temperature rising inflation before contraction; Coarse aggregate, mortar and concrete samples with the rise of temperature has been expanding. Cooling process, the five samples with the decreasing of temperature has been shrinking.5. The thermal expansion properties of five kinds of samples analyzed, preliminary explained the mechanism of sand after high temperature mechanical properties of high performance concrete reasons for such changes.