Studying Of The Strength Reinforced Mechanism Of The LSFRC And LHFRC

Fiber reinforced concrete is a kind of heterogeneous material, which is more increasingly used in civil engineering. The incorporation of steel or other fibers in concrete can significantly improve the performance of cementitious materials, such as tensile strength, toughness, and ductility as well as resistance to crack and fatigue.Layer Steel Fiber Reinforced Concrete (LSFRC), which is on the basis of considering economy and improvement of material properties, letting steel fiber layer distributing layer by layer, and steel fibers are scattered to the upper and lower layer, concrete which is cast by this method, is called LSFRC. For the disadvantage of inferior toughness, crack resistance and infiltration resistance of the middle layer, polypropylene fibber are mixed entirely in the concrete, for the purpose of exerting the "positive intermixing effect" to improve the performance of the concrete.Our researchers have accomplished lots of test since 1997, it is indicated that LSFRC and LHFRC (Layer Hybrid Fiber Reinforced Concrete) are provided with excellent properties on multi-aspect, such as: flexural strength, fatigue resistance , crack resistance, durability, etc. The current researches on the reinforced mechanism of fiber reinforced concrete are mainly concentrated on macro experiments and qualitative analyses, mature mesoscopic models are still absent. The quantitative analyses of the relationship between the meso-structural and macroscopic response are even fewer. So studying its reinforced mechanical essence absolutely and expounding its reinforced mechanism theoretically is the premise of this new composite material becoming extensive use.This article main content as follows:1. Some examinations had been made to test the flexural strength of the LSFRC, and some parameters which effected the properties of LSFRC were analyzed.2. A statistics mechanics model was made to analyse the relationship between the meso-structural and macroscopic response of the LSFRC and LHFRC.3. A crack developing model was made to simulate the developing of the cracks of the LSFRC and LHFRC.