The Experimental Study On Nonasbestos Fiber Reinforced Cement's Interface Optimized By Silicon Fume

Fiber reinforced cement-based composite is composed of cement paste, mortar as matrix, no continuous short fiber or continuous long fiber as reinforcement. Among the fiber reinforced cement, reinforcement and matrix have huge difference in the performance and limited consistent nature, their interfacial bond is brittle. Thereby, it's very essential to optimize interface, improve interfacial composing, fabric and performance by the scientific techniques. Silica fume added is one of these techniques.This thesis is based on the experimental study of nonasbestos fiber reinforced cement's interface optimized by silicon fume. Firstly, physical-mechanics performance of fiber cement influenced by silica fume (bend strength, impact strength, water absorption, density, drying shrinkage) is studied principally; secondly, silica fume's effect is analyzed in the durability : freeze-thaw resistance, heat-rain resistance; physical-mechanics performance of fiber cement which is influenced by different kind of silica fume, different dispersion degree, different addition order of silica fume is also studied. Finally, mechanism of fiber-cement's interface optimized by silica fume is especially discussed.The results shows that silica fume influence remarkably physical-mechanics performance of nonasbestos fiber-reinforced cement: improve bend strength and impact strength,lower water absorption,increase density and drying shrinkage . It also enhance evidently the durability of nonasbestos fiber reinforced cement, specimen's strength with silica fume is bigger than blank specimen after the durability experimentation. Silica fume's dispersion degree has also very important effect on physical-mechanics performance of nonasbestos fiber reinforced cement. Thereby, we should assure that silica fume has good dispersion in the production.By microcosmic analysis between blank specimen and specimen with silica fume, we can draw a conclusion that cumulative pore volume and pore diameter of fiber cement is reduced by addition of silica fume, hydration product calcium ydroxide lowered, calcium-silicate hydrate is increased, microscopical rigidity between the interfacial of fiber-cement is enhanced.