Study On Mechanical Performance And Permeability Resistance Of Hybrid Fiber Reactive Powder Concrete

With the constant progress of science and technology, new building materials have developed. As the perfect combination of high strength concrete and fiber reinforced concrete, reactive powder concrete has been used in many fields for its high mechanical properties and good durability. Therefore it has been widely used in bridges, tunnels and nuclear engineering.In view of the steel fiber that added in traditional reactive powder concrete is easy to rust and the cost is higher. So in this paper we use basalt fiber to replace steel fiber, and mixed with polypropylene fiber to make Hybrid fiber reactive powder concrete to explore the mechanical properties and durability of hybrid fiber reactive powder concrete. Specific work as follows:1.Through the orthogonal experiment to design HFRPC mixture, the selection of water/cement ratio, sand cement ratio and cement/fly ash, dosage of water reducing agent, basalt fiber as the factors, according to the test precision requirement to set the corresponding level. And according to the compressive strength and flexural strength, via Poor method of RPC to obtaine the optimal formula of matrix.2. On the basis of the optimal proportion, explore mechanics propertie difference between hybrid fiber reactive powder concrete and single basalt fiber, When the high elastic modulus fiber dosage is small, low elastic modulus fiber content increase will not cause the strength of the surge. In terms of compressive strength, high modulus fiber plays a dominant role. On flexural strength, low elastic modulus fiber number per unit volume, fiber distributed inside the substrate evenly, effectively prevent the development of micro cracks, tiny fiber also can cross crack and continue to bear the shear force, to make the matrix of flexural strength growth significantly.3.Under standard curing condition and 90 ℃ hot water curing condition,on compressive strength of hybrid fiber RPC specimens were studied, it is concluded that hybrid fiber RPC specimens is one of the biggest strength in the 28 d under standard curing conditions, Hybrid fiber RPC specimens can reach more than 95% of the ultimate strength in 7 d under the condition of 90 ℃ hot water curing. It can shorten curing time under 90 ℃ hot water curing, in order to implementation large-scale popularization and implementation of the RPC in Certain theoretical basis for future.4.Select the basalt and polypropylene fiber, single basalt fiber, single mixing polypropylene fiber reactive powder concrete, Using the method of electric flux permeability performance experiment was carried out,to study the seepage resistance and inferiority. Capability of hybrid fiber RPC on less than single doped fiber RPC permeability resistance, including single best mixing polypropylene fiber RPC permeability resistance.5. By electron microscope scanning,to study of factors affecting permeability in RPC good or bad from the Angle of the micro, and based on RPC permeability, permeability after SEM image contrast, using to the micro morphology of the hybrid fiber RPC and single doped fiber RPC permeability performance to demonstration...