Experimental Study On Bearing Capacity Of Self-compacting Lightweight Aggregate Concrete Beams

SCLC(Self-compacting Light Aggregate Concrete)is a new type of high-performance concrete,which combines the advantages of self-compacting concrete(SCC)and lightweight aggregate concrete(LAC).SCLC has a high intensity and an small density.It can save resources and improve the environment;Self-compacting lightweight aggregate concrete components not only have good thermal insulation and durability,but also have better seismic resistance than ordinary concrete.As a new type of building material,self-compacting lightweight aggregate concrete can bring environmental benefits,as well as good social and economic benefits.At present,the research content of self-compacting lightweight aggregate concrete mainly includes physical and mechanical properties research,work performance research,durability research,and mix ratio design research and so on several aspects.However,the research on the properties of reinforced self-compacting concrete member stress is more less.Therefore,in this paper,the mix proportion of self-compacting lightweight aggregate concrete suitable for this experiment was obtained through trial fitting,and then the mechanical properties of self-compacting lightweight aggregate concrete were measured.By designing the test beam,the loading scheme is defined,and then the flexural bearing capacity of the self-compacting lightweight aggregate concrete beam is tested.The research and achievements of this paper are as follows:(1)Follow the ordinary concrete mix design method to prepare ordinary concrete with strengths of C40 and C50.According to the relevant provisions of self-compacting concrete and the reference lightweight aggregate concrete design method,formulate the mix ratio of SCLC40 and SCLC50 self-compacting lightweight aggregate concrete.(2)Compressive strength test,splitting tensile strength test,elastic modulus test,and stress-strain curve of self-compacting lightweight aggregate concrete are performed according to the test methods for mechanical properties of ordinary concrete.Through analysis of test results show that the self-compacting light-weight aggregate concrete and ordinary concrete have the similar failure shape and stress-strain curve.And obtained the self-compact light-weight aggregate concrete strength conversion relationship,the elastic modulus calculation formula,the stress-strain curve equation.(3)According to the concrete structure test method standards,the test of the normal section bearing capacity of the self-compacting lightweight concrete beam was carried out.,it was found that the process of the concrete test beams from the beginning to the end of the load was similar to that of the ordinary concrete beams.They all experienced three stages,namely before concrete cracking and the uncracked stage,the working stage with cracks,and the destruction stage.The flat section assumption applies to self-compacting lightweight aggregate concrete beams.Under the same reinforcement ratio,the cracking moment and ultimate bending moment of self-compacting lightweight aggregate concrete beams are slightly lower than those of ordinary concrete beams with the same strength.The number of cracks in self-compacting lightweight aggregate concrete beams increases with the increase of reinforcement ratio,and the interval between cracks is also getting smaller and smaller.(4)The test discussed the calculation formula of the ultimate bearing capacity of the self-compacting lightweight aggregate concrete beam and the applicability of the current specification to the cracking moment of the test beam through the measured mechanical properties of the concrete.The formula for the ultimate bearing capacity in the current "Specification" is applicable to the calculation of self-compacting lightweight aggregate concrete members.When calculating the cracking moment of self-compacting lightweight aggregate concrete beams,it is necessary to multiply the original formula by a correction factor of 0.66.