Change Rule Of SHPB Impact Performance Of Semi-lightweight Concrete Under Water-saturated

Lightweight aggregate concrete(LWAC)is inevitably subjected to static load and dynamic load in the application of underwater engineering construction and safety protection.Through uniaxial and conventional triaxial static tests of all-lightweight concrete(ALWC)under saturated condition,it is found that its strength has softening effect.In order to compare and analyze the static and dynamic properties of different kinds of lightweight aggregate concrete under saturated condition,this paper takes the All-lightweight concrete(ALWC)as the reference,and replaces the partial lightweight aggregate by the method of equal volume ratio of conventional aggregate,respectively,resulting in sand lightweight concrete(SLWC)and gravel lightweight concrete(GLWC)and hybrid aggregates lightweight concrete(HALWC),collectively referred to as semi-lightweight concrete(semi-LWC),have the greatest advantages of ALWC and Normal weight concrete(NWC)and overcome their respective defects to the maximum extent;then the uniaxial and multiaxial static tests and Split Hopkinson Pressure Bar(SHPB)impact tests were carried out under dry and saturated conditions respectively.The content is as follows:(1)The pore structure parameters and influencing factors of shale ceramsite and pottery sand were tested and analyzed,and the law of water absorption change of semi-LWC with different soaking time was analyzed;(2)The statics performance indexes of semi-LWC,such as characteristic strength,stress-strain curve and elastic modulus,were compared and analyzed under dry and saturated conditions;(3)Through the SHPB impact test of saturated water ALWC and GLWC under uniaxial condition,it is found that its dynamic characteristic parameters and total energy consumption have obvious strain rate effect.Among them,the peak stress,peak strain and total energy consumption increase with the increase of strain rate,and the peak stress and total energy consumption of GLWC are higher than that of ALWC;(4)Through the SHPB impact test of saturated water ALWC and GLWC under confining pressure,it is found that the peak stress has obvious strain rate effect and confining pressure effect.The peak stress increases with the increase of strain rate.Under the same impact pressure,the peak stress increases with the increase of confining pressure.Under the action of confining pressure,the peak stress is significantly higher than that of uniaxial stress,and the lifting range of ALWC is larger than that of GLWC;(5)According to the comparison of static and dynamic mechanical properties of ALWC and GLWC under saturated condition,the dynamic strength growth factor is large,but the dynamic deformation growth factor is small,and the mechanism of the difference is analyzed.