Experimental Study On Mechanical Properties Of Crumb Rubber Modified Concrete After High Temperature

Crumb rubber concrete is a composite material of civil engineering as the substrate ofconcrete, and made of the incorporation of powder or particles. As a hyperelastic material,rubber mainly improving the internal structure of concrete by the physical effects, withoutchanging the chemical properties of the concrete components, the incorporation of the rubbercan significantly improve the fragility of concrete, and the concrete exhibit significantlyductility under external loads, and can also improve the damping of concrete, impactresistance, prevent burst, noise insulation and other properties; It effectively solves theproblem of waste rubber processing while improving the performance of concrete, and is a hotresearch topic. But most research have focused on the performance of crumb rubber concreteat room temperature, for high-temperature properties of rubber concrete was rare in relatedresearch. Firstly, the mechanical properties of rubber concrete were tested at roomtemperature under this study, to choose the optimum rubber particle size which least impacton the strength of concrete, and then some concrete specimens were prepared by the optimumrubber particle size; The high-temperature tests were conducted at different temperatures,focus on the basic mechanical properties of rubber concrete after elevated temperature, toprovide a reference for the relevant research of rubber crumb concrete. Details are as follows:（1）30mesh,1-3mm and3-5mm three different rubber particle sizes of rubber particleswas incorporated fine aggregate concrete by equal volume alternative methods respectively,three groups of rubber concrete specimens were produced, the work performance of freshrubber concrete and apparent density after curing of rubber concrete were measured. whileconducting research the performance of natural sand rubber concrete, an equal number ofmanufactured sand rubber concrete specimens were tested, the basic mechanical properties ofcube compressive strength, splitting tensile strength, flexural strength were studied, thedifferences of the mechanical properties between natural rubber sand and manufactured sandof concrete were compared, and the optimal particle size which was minimal impact on thestrength of concrete in the three kinds of rubber particle size were elected.（2）The rubber concrete specimens were formulated by the optimum rubber particle size determined by the test at room temperature, and after curing28d under standard conditions,300℃,500℃and700℃high temperature test was conducted respectively, the phenomenaof the different rubber content specimens at different high temperature test were recorded;The apparent changes of the specimens after high temperature and the mass loss wereanalyzed; And it were compared with the specimens at room temperature. At the same time,thermocouples were buried at different locations in the specimens, the thermal conductivityand temperature fields of rubber concrete under high temperatures were studied.（3）The basic mechanical properties test of rubber concrete specimens after hightemperature were conducted, including: cube compressive strength, splitting tensile strength,axial compressive strength, elastic modulus and other tests; The test results were comparedwith the test results at room temperature; The stress-strain relationship of rubber concreteunder uniaxial compression after high temperature were determinated, and the regressionanalysis of the test results were produced, the mathematical relationships which in simpleform between stress-strain and rubber content of concrete after high temperatures were given.