Preparation And Research Of High Strength Light Weight Aggregate Concrete

With the development of modern civil engineering,people's demand for construction materials increasingly becomes higher and higher.However,since the self-weight of ordinary concrete is too large,it is difficult to meet the requirements of special architectural structure,while lightwe ight aggregate concrete can compensate for this defect because of its characteristics of light-weight but high strength,good seismic performance,insulation and better comprehensive economic.Therefore,high-strength lightweight aggregate concrete is grad ually being used in building construction.Due to the influence of China's current situation of lacking in high-performance lightweight aggregate,the current strength of high-strength lightweight aggregate concrete is mainly less than LC50,and the amount of high-strength lightweight aggregate concrete is quite smal.Therefore,this research was carried out with pozzolana ceramic produced by Tianjin Baoming company,and aimed to study the preparation and the physical and mechanical properties of lightweight aggregate concrete:(1)The research first probed into the influence of cementitious material,water-cement ratio and sand ratio to the strength and density of concrete,and then optimized the design of mix proportion and drew the standard mix proport ion.,based on which the test mix proportion was obtained.After that,we carried out strength and density test,and prepared three high-strength lightweight concrete whose intensity level were respectively LC50,LC60,LC70,and density rating were 1700,1800,1800kg/m3.(2)The research studied the physical and mechanical properties of the three high-strength lightweight aggregate concrete with the intensity level of LC50,LC60 and LC70,and then compared with the ordinary high-strength concrete of the same level.Results showed that the strength of high-strength lightweight aggregate concrete was 40%-60% higher than ordinary high-strength concrete,the use of lightweight aggregate concrete structures could greatly reduce the weight of the structure;other properties were consistent with the ordinary high-strength concrete.(3)The test also performed on the brittle strength of high-strength lightweight aggregate concrete and ordinary high-strength concrete.When the size of specimen was 100 mm,the size conversion factor of the cube compressive strength of lightweight aggregate concrete was 0.874-0.917,and the size conversion factor of splitting tensile strength was 0.870-0.879;the size conversion factor of the cube compressive strength of ordinary concrete was 0.878-0.924,and the size conversion factor of splitting tensile strength was 0.844-0.864.(4)This paper proposed two approaches of toughening brittle drop for the brittle strength of high-strength lightweight aggregate concrete,that is,to use rubber with the same volume to replace fine aggregate and to add polypropylene fiber.The experiment showed that both of the two approaches could increase the toughness of lightweight aggregate concrete.Under the circumstances of the same mix proportion,the method of adding polypropylene fiber was more favorable.