Experimental Study On The Effect Of Rubber Particle Size And Content On The Performance Of Self-compacting Concrete

Rubber has caused serious environmental pollution,resulting in a huge amount of solid waste.In order to develop the environmental protection and energy-saving new materials,the system is upgrading its key technical performance,on the basis of normal self-compacting concrete,this article selects three different rubber particle size(0.15 ~ 0.25 mm,0.38 ~ 0.55 mm,1 ~ 3 mm)and three different dosage(5%,10%,15%),rubber etc.Replace the fine aggregate volume,preparation of self-compacting concrete,the rubber on its working performance,mechanical property and frost resistance performance has carried out experimental study.Specific research contents and results are as follows:(1)The rubber self-compacting concrete was tested for slump extension,flow time,j-ring slump extension,j-ring inside and outside height difference,and other performance tests,and the test results were compared and analyzed to study the influence of rubber particle size and substitution rate on the performance of self-compacting concrete.The results show that the addition of proper amount of rubber powder(particles)can improve the performance of self-compacting concrete,and the optimal rubber particle size is 0.15-0.25 mm,with the substitution rate being 10%.(2)The cube compressive strength,splitting tensile strength,axial compressive strength,flexural strength,elastic modulus and other basic mechanical properties of rubber self-compacting concrete were tested respectively,and the tensile compression ratio and flexural compression ratio were studied.The regression-fitting relationship between the splitting tensile strength,axial compressive strength,flexural strength and cubic compressive strength of rubber self-compacting concrete is preliminarily established,and the rationality of the theoretical model is verified by the test data.The experimental results show that the addition of rubber powder(particles)will reduce the mechanical properties of rubber self-compacting concrete,but improve the ductility of self-compacting concrete.(3)By combining the strain gauge method and the displacement sensor method,the full curve of stress-strain relationship derived from compacted concrete is drawn.The failure pattern and stress-strain curve of self-compacting concrete were studied.Matlab was used to establish the linear fitting equation between the stress-strain rising curve of rubber self-compacting concrete and the rubber substitution rate.The constitutive model of rubber self-compacting concrete is established.(4)For rubber self-compacting concrete prism,specimens using freezing method to freeze-thaw cycling test,the determination of the rubber self-compacting concrete under freeze-thaw cycles of mass loss rate and relative dynamic elastic modulus,and after 200 times of freeze-thaw cycle of cube compressive strength and splitting tensile strength,set up related to rubber to replace rate model of the relative dynamic elastic modulus.The results show that rubber can effectively improve the frost resistance of self-compacting concrete,and the frost resistance is the best when rubber particle diameter is 0.15-0.25 mm and substitution rate is 15%.