Experimental Study On Mechanical And Cracking Properties Of Rigid Rubber Concrete Foundation

At present,the use value of rubber concrete more and more people pay attention to,in the use of rubber particles into its,can significantly reduce the strength of concrete,compared with the general concrete its crack resistance,frost resistance,deformation resistance and other properties significantly improved.As a new type of building material,dry and hard concrete has the characteristics of high strength,fast construction speed and relatively dry and hard mixture,so it is suitable for dam construction and highway construction.However,the unit water consumption of hard concrete is small,and it is easy to crack,which is quite unfavorable to its application and popularization in engineering.If a proper amount of rubber particles are mixed into the dry and hard concrete,the crack resistance can be improved,which is of great significance.The influence of rubber particle size and mixing amount on compressive strength,bending strength,splitting strength and cracking performance of dry hard concrete was studied,The results show that:1、It is found that the compressive,flexural and splitting strengths of dry and hard rubber concrete are lower than those of the reference group after the addition of rubber particles in the same volume instead of sand.Three different sizes of rubber granules with average rubber particle size of 2.36 mm,1.18 mm and 0.6mm were mixed into dry and hard concrete by the same volume of replacement sand to make cubic test blocks.The replacement rates of rubber granules were 0,5%,8% and 11%respectively.The compressive,flexural and splitting strength of dry and hard rubber concrete was determined after 28 days of curing.It is found that with the decrease of rubber particle size or the increase of rubber particle content,the compressive strength,flexural strength and splitting strength of dry and hard concrete show a decreasing trend.2、Through the unconstrained cracking test of concrete,dry and hard concrete with 0,5%,8% and 11% rubber content is made into beams by the method of replacing sand by the same volume.Three prefabricated joints with 5 cm,6 cm and 7cm,and dry and hard concrete slabs with 0,5% rubber content and three prefabricated joints with 8 cm,9 cm and 10 cm are set respectively under the same strength condition.The cracking time of the prefabricated joints is determined.It is found that the deeper the prefabricated joint is,the shorter the cracking time is.When the prefabricated joint depth is fixed,the more rubber particles are added,the longer the cracking time of dry concrete slab and tray is,the better the cracking resistance is,and the rubber particles can delay the time of cracking.3、Through the eccentric restraint test of outer inner circle,through the research on the crack resistance of different rubber content(0,5%,8%,11%)and different rubber particle sizes(0.6mm,1.18 mm,2.36mm),it was found that the addition of rubber particles or the decrease of rubber size could delay the cracking time.It can be seen from this that rubber particles have obvious effects on prolonging cracking time and improving cracking performance of concrete.The incorporation of rubber particles restrains the crack propagation speed and compensates the shrinkage of concrete.