Study On Preparation Principle And Basic Mechanical Properties Of Reactive Powder Concrete

Reactive Powder Concrete(RPC)is an ultra-high performance concrete with high strength,good toughness and excellent durability,and has wide application prospect in China's future infrastructure construction.Since the late 90 s of last century,our scholars made more research results on the preparation of RPC and mechanical properties of a certain study.But RPC preparation method is not uniform,the specimen size range of large span,high strength needs to be achieved through high temperature curing,and RPC is not easy to engineering applications.2015 national standard "reactive powder concrete" GBT 31387-2015 on the preparation of RPC and test methods were unified,In this paper,based on the new national standard,the experimental study on the fabrication,compression and flexural properties of RPC was carried out,the conclusions can be used for the application of RPC.The main contents of the thesis include four aspects:(1)Based on the raw materials of the region,according to the close accumulation theory,through a large number of test with the test,the optimal mix design was put forward.Summed up the preparation method,optimized system preparation and maintenance system,RPC optimal mix ratio and general preparation method were put forward.(2)The effects of factors such as curing system,age,water / cement ratio,steel fiber content,silica fume content,quartz powder content and sand ratio on RPC compressive strength were studied by cube compression test.Based on the Boromi formula,the RPC compressive strength calculation model is proposed.The stress-strain curves of the RPC axis under different mixing ratio are established.The effects of different factors on the peak strain,elastic modulus and Poisson 's ratio of RPC were analyzed.(3)The RPC bending performance test was carried out,and the damage characteristics and flexural strength were analyzed,and the influence law of different factors was discussed.The fracture toughness and energy dissipation capacity of RPC were studied by the load-deflection curve of different steel fiber.Two methods of bending toughness of concrete(bending toughness method and residual strength method)were analyzed and compared.(4)Based on the experimental data,the relationship between RPC coefficient of variation and compressive strength was analyzed,and the compressive strength grade of RPC was divided.The compressive strength,axial compressive strength,peak strain,elastic modulus and other related parameters of the cube are established.The coefficient of the material is obtained from the target reliability,and the values of the parameters are put forward under different intensity grades.