Experimental Study On Mechanical Properties Of High Strength Concrete Column After Water Cooling At High Temperature

Fire is the most frequent disaster that human beings are facing.The uncertainty of its occurrence makes it difficult to predict,and if it happens,if there is no good measure,it will cause huge property losses and casualties.China is a large country with multiple fires.It is very necessary and urgent to study the fire resistance of building structures after fire.In addition,Because of large population and certain area,buildings are becoming more and more towering,large-span,and high strength concrete is used to it.It is necessary to study the performance of high-strength concrete after high temperature.Furthermore,water spraying cooling is generally used in fires,which is inconsistent with natural cooling studied by most scholars,and the performance of water spraying cooling is not the same as that of natural cooling.Therefore,our research group has studied the high strength concrete after spraying cooling at high temperature,and has carried on the exploration research through the experiment to its mechanical property,in order to provide the experiment and the theoretical basis for the spraying cooling at high temperature high strength concrete column application popularization in the project.In this paper,forty-five standard cylindrical specimens and sixteen high strength concrete column specimens were designed to test with temperature,cooling mode,reinforcement ratio,stirrup ratio and constant temperature time.The failure process and shape of the specimens after high temperature were observed.Based on the experimental data,the bearing capacity of various parameters was analyzed.The influence law of load.At the same time,the formula for calculating the axial compression of high strength concrete columns after high temperature spraying cooling is proposed by modifying the formula of the code.The formula is in good agreement with the measured data.The results show that the color of sprinkler-cooled high-strength concrete changes from grey to red at high temperature,and from grey to white at 800?,the specimens have basically lost their bearing capacity at 800 ?.Temperature has a significant effect on the mechanical properties of the specimens.Finally,on the basis of the test,a preliminary discussion is made on the evaluation and appraisal of spray-cooled high strength concrete by rebound method.