Study On Mechanical Property And Energy Characteristic Of Ultra High Strength Rubber Concrete

In order to solve the engineering application problems of low mechanical strength and poor toughness of Rubber Concrete(RC)and strengthen its anti-penetration ability,this paper innovatively proposed a method to co-regulate the macro mechanics and deformation behavior of RC by reducing the water-cement ratio and adopting steel fiber and silica fume.So,Ultra High Strength Rubber Concrete(UHSRC)was prepared.In this paper,the static compression test and static splitting test of UHSRC specimens were carried out by using the electro-hydraulic servo universal testing machine.The crack initiation mechanism and the cooperative deformation principle of fiber-rubber-silica slurry in cement matrix were analyzed from macro and micro perspectives,and then the failure mechanism and energy evolution characteristics of UHSRC specimens were revealed.Then,the former machine was used to carry out cyclic loading and unloading test on High Strength Rubber Concrete(HSRC)specimens.The relationship between the number of cycles and the rubber substitution rate and the loading deformation modulus,unloading deformation modulus,loading strain,cumulative residual strain,total input energy,elastic strain energy,dissipated energy,cumulative residual strain damage and energy dissipation damage was discussed.Finally,the dynamic compression test and dynamic splitting test were carried out on UHSRC specimens by Hopkinson compression bar(SHPB).The internal relationships among impact load,rubber replacement rate,rubber particle size and steel fiber and strength,deformation,failure degree,fracture energy,reflected energy,transmitted energy and absorbed energy were analyzed.The results show that:(1)Both HSC and UHSRC were not simply compressive failure.Instead,the compression load forced the local part of the specimen to reach the tensile limit first,thus resulted in tensile cracks,or then developed into shear cracks.Finally the failure was caused by the loss of bearing capacity due to the penetration of tensile cracks or tension-shear cracks.(2)Based on the stress-strain curves,the energy could be divided into five stages.Initial damage caused by micro-plastic compaction(energy dissipation mechanism played a leading role),damage stabilization caused by initial defect compaction(energy storage mechanism played a leading role),sudden damage caused by local plastic deformation(energy storage mechanism played a leading role),accelerated damage caused by sudden failure(energy dissipation mechanism played a leading role),and damage deceleration caused by near residual bearing capacity(energy dissipation mechanism played a leading role).(3)With the increase of the number of cycles,the loading deformation modulus,unloading deformation modulus,loading strain,cumulative residual strain,total input energy,elastic strain energy,dissipated energy,cumulative residual strain damage and energy dissipation damage increased gradually.Moreover,because rubber and steel fiber cooperate to resist cracking step by step and multi-level,the loading strain,cumulative residual strain and cumulative residual strain damage of HSSFC were greater than those of HSRC,but the dissipated energy and energy dissipation damage were smaller than those of HSSFC.(4)Because rubber particles absorbed energy by elastic vibration reduction,and at the same time produced compression deformation in the axial direction to make way,while its transverse expansion pressed the adjacent matrix,and the steel fiber dissipated energy using restraint,UHSRC showed ductile fracture in the dynamic impact process,and the failure mode was "crack but not scattered",not HSC showed brittle fracture.Figure [46] Table [9] Reference [35]...