Experimental Study On Mechanical Properties Of Glass Fiber Shale Vitrified Concrete

The performance advantages of light-aggregate concrete meet the development requirements of lightweight and high-strength concrete and multifunctional,but the small modulus of elasticity of light-aggregate concrete has a negative impact on stiffness and strength,which limits its application in load-bearing structures.Therefore,the research on the mechanical properties of light aggregate concrete members should be strengthened to provide a test basis for its promotion in practical engineering.In this paper,fly ash,silica fume and glass fiber are used as test factors,and the influence law of each test factor on the basic mechanical properties of glass fiber shale vitrified concrete is investigated through orthogonal tests,and the optimal level combination is derived.The mechanical properties of the test beams were tested in the bending section under the optimal level combination,and the damage mechanism and bending properties of the test beams were analyzed.The main research contents and conclusions are as follows:(1)Nine groups of orthogonal tests with three factors and three levels were designed to explore the effects of fly ash replacement rate(15%,20%,25%),silica fume replacement rate(5%,7%,10%)and glass fiber content(0.4%,0.6%,0.8%)on the basic mechanical properties of glass fiber shale ceramsite concrete.The optimal combination of fly ash replacement rate of 15%,silica fume replacement rate of 10% and glass fiber content of 0.6% was determined by range analysis.(2)The concrete strains in the span of both glass fiber shale vitrified concrete beams and shale vitrified concrete beams conform to the flat section assumption,and the flexural damage morphology is similar for all tested beams,which can be specifically divided into elastic working stage before cracking,working stage with cracks,and ultimate damage stage.(3)The incorporation of glass fiber can inhibit the development of cracks in shale ceramic concrete beams.The maximum crack width of glass fiber shale ceramic concrete beams is smaller than that of shale ceramic concrete beams under the same load level;under the limit condition of normal use,the maximum crack width of the test beams are all less than 0.3mm,meeting the specification requirements.(4)The incorporation of glass fiber improved the flexural performance of shale vitrified concrete beams and narrowed the gap with the deformation performance of ordinary concrete beams.(5)The incorporation of fly ash,silica fume and glass fiber increased the positive cross-sectional bearing capacity of the glass fiber shale vitrified concrete beams by21.8% in cracking load and 10.6% in ultimate load compared with the normal shale vitrified concrete beams.Analyzing the difference between the tested and calculated values,it can be determined that it is safe and feasible to design the positive cross-sectional bearing capacity of glass fiber shale ceramic concrete beams with shale ceramic concrete beams with reference to the current code.