Research On The Performance And Application Of Self-compacting Lightweight Elastic Concrete

Based on the existing research of “self-compacting lightweight aggregate concrete” and “rubber concrete”,the rubber particles were firstly blended into self-compacting lightweight aggregate concrete to prepare a new green environment building materials(self-compacting lightweight elastic concrete)with outstanding performance of self-compacting,lightweight and elasticity.The material has the advantages of self-compacting lightweight aggregate concrete and rubber concrete,while overcoming the shortcomings of both,owning a widely application prospect.In order to systematically study the workability and main static and dynamic characteristics of self-compacting lightweight elastic concrete,explore the application prospect on the field of light weight house floor,floor system and power equipment foundation,the following research contents were carried out:1.Self-compacting lightweight elastic concrete was developed for the first time and the research of workability was carried out.On the basis of the mix proportion design method of self-compacting lightweight aggregate concrete,the self-compacting lightweight elastic concrete with excellent workability was prepared by mix proportion optimal design and repeated test.Effects of rubber particles on the working performance of the self-compacting lightweight elastic concrete and the mortar slurry in the self-compacting lightweight elastic concrete were studied.The results show that the mortar slurry which is prepared as the sand replaced by rubber particles at the same volume is still Bingham fluid.The self-compacting lightweight elastic concrete has good working performance,meanwhile,self-compacting effect can be realized.A good linear correlation between the workability of self-compacting lightweight concrete and the rheological properties of mortar was obtained.2.The static characteristics of self-compacting lightweight elastic concrete were investigated systematically.(1)The change rule of the dry apparent density(28d),cubic compressive strength,axial compressive strength,tensile splitting strength,flexural strength and elasticity modulus of self-compacting lightweight elastic concrete were studied.The results show that with the increase of the replacement rate of rubber particles,the dry apparent density(28d),cubic compressive strength,axial compressive strength,tensile splitting strength,flexural strength,elasticity modulus and specific strength of self-compacting lightweight elastic concrete decreases,the ratio of tension-compression and bending-compression increase.(2)The prismatic uniaxial compression stress-strain curves of self-compacting lightweight elastic concrete were measured and the constitutive model of uniaxial compression stress-strain is established.The results show that with the increase of the replacement rate of rubber particles,the peak stress of self-compacting lightweight elastic concrete decreases,the peak strain increases,the descent stage of the concrete stress-strain curve becomes gradually flattened,and the failure process tends to be ductile damage.(3)The total shrinkage strain of self-compacting lightweight elastic concrete at different ages were tested.Based on the model of China building science research institute,the shrinkage strain prediction model of self-compacting lightweight elastic concrete was established.The results show that with the increase of the replacement rate of rubber particles and age,the shrinkage strain of self-compacting lightweight elastic concrete increases.The shrinkage strain prediction model proposed in this paper can be used as the prediction model of total shrinkage strain at each age of self-compacting lightweight elastic concrete.3.The main dynamic characteristics of self-compacting lightweight elastic concrete were investigated systematically.(1)The fatigue strain,residual strain and fatigue life of self-compacting lightweight elastic concrete under uniaxial compression were detected.Based on the reliability theory,the double logarithm fatigue equation with different failure probability was established.The results show that the fatigue strain curve and the residual strain curve are generally consistent with the three-stage model.The Weibull distribution model can be used to analyze the fatigue life of self-compacting lightweight elastic concrete accurately.When the rubber particle replacement rate is 30%,the fatigue performance of self-compacting lightweight elastic concrete is best.(2)The vibration time-history curve of self-compacting lightweight elastic concrete cantilever beam with different damage degrees were tested.The laws of damping ratio and the fundamental period variation were analyzed.The damage index was defined and the relationship between the damping ratio of the self-compacting lightweight elastic concrete and the damage index was established.The results show that the incorporation of rubber particles significantly improves the damping performance of self-compacting lightweight elastic concrete.With the increasing of damage control displacement,the damping ratio of self-compacting lightweight elastic concrete cantilever beam increases first and then decreases,the fundamental frequency decreases.At the same damage index,the damping ratio increases with the increase of the rubber particle replacement rate.With the increase of the damage index,the damping ratio increases first and then decreases.4.The self-compacting lightweight elastic concrete was used in the composite slab,the composite floor and power equipment foundation for the first time,and the exploratory research on its performance was carried out.(1)Four profiled steel sheets-self-compacting lightweight elastic concrete composite slab were designed and fabricated.The self-compacting lightweight elastic concrete with no rubber particles and the self-compacting lightweight elastic concrete with rubber particles at 30% replacement ratio were used as concrete.The shear span were 450 mm and 800 mm respectively.Based on the system analysis of the failure modes,failure process,bearing capacity,deformation and slip of the composite slab,the calculation method of the flexural capacity of the normal section of the profiled steel sheets-self-compacting lightweight elastic concrete was proposed.(2)The cold-formed thin-walled steel-self-compacting lightweight elastic concrete composite floor model was established by using ABAQUS software.The vibration comfort performance of self-compacting lightweight elastic concrete composite floor with different rubber particle replacement rate was analyzed.(3)The three-dimensional finite element model of the interaction between the foundation-large-scale concrete foundation-dynamic equipment was established by ANSYS software.The damping effect of power equipment vibration load on the foundation of ordinary concrete and self-compacting lightweight aggregate concrete with no rubber particles and self-compacting lightweight elastic concrete with rubber particles at 30% replacement ratio were contrastively analyzed.In this paper,the working performance and main static and dynamic performance of self-compacting lightweight elastic concrete were studied systematically.The feasibility in the application of composite slab,composite floor and power equipment foundation were demonstrated.The foundation of popularization and application of self-compacting lightweight elastic concrete will be settled.