Mechanical Properties Of Steel Fibers And Nano Silica Modified Crumb Rubber Concrete Subjected To Elevated Temperatures

Steel Fibers and Nano-Silica modified Crumb Rubber Concrete(SFNS-CRC)is a new type of environmental and friendly high performance concrete.Steel fibers and nano-silica can improve the strength of rubber concrete,make up for the low strength of rubber concrete,and expand the engineering application range of crumb rubber concrete.In this paper,the effects of steel fiber volume fraction,nano-silica content,temperature and rubber volume content on rubber concrete strength were studied through experiments.The failure mode,the mass loss,the compressive and splitting tensile strength subjected to elevated temperatures were analyzed.The failure mechanism was studied based on microscopic analysis.The main contents are as follows:(1)The optimum mix ratios of steel fibers and nano-silica modified crumb rubber concrete were determined according to the work performance rest.The effects of steel fiber volume fraction and nano-silica content on the compressive and splitting tensile failure modes,compressive strength and splitting tensile strength of crumb rubber concrete were studied by compressive test and splitting tensile test.(2)Compared with the mechanical properties at room temperature,the effects of temperatures,steel fiber volume fraction and nano-silica content on the mass loss,failure mode,compressive strength and splitting tensile strength of rubber concrete subjected to elevated temperatures were studied.(3)The relationship between steel fiber volume fraction,nano-silica content and temperatures on the strengths of steel fiber and nano-silica modified crumb rubber concrete was analyzed,and the calculation method of compressive strength and splitting tensile strength of steel fiber and nano-silica modified crumb rubber concrete subjected to elevated temperatures was established.(4)The SEM scanning electron microscopy and XRD phase analysis were used to study the effects of temperature and nanomaterials on the morphology and phase change of steel fibers and nano-silica modified crumb rubber concrete.The failure mechanism of steel fibers and nano-silica modified crumb rubber concrete was discussed.