According to theoretical and experimental results at home and abroad, compared with ordinary concrete, mechanical properties of steel fiber reinforced concrete significantly improved tensile strength and can be increased by about 2-fold, bending strength is 2.5-3.5 times that of ordinary concrete flexural strength, sandblasting material improve the impact strength is more obvious, generally up to 5 times more than ordinary concrete, and even up to 20 times.
Currently, the mechanism of steel fiber reinforced concrete, there are two different interpretations. One is the fiber spacing mechanism proposed by waterjet abrasives the United States Rmuald; One is composite mechanism England Swamy, Manga and others made. Here we analyze the main fiber spacing mechanism.
Fiber spacing mechanism is based on the basis of linear elastic fracture mechanics description of a constraint fiber up to the occurrence and development of cracks. The mechanism that in the concrete originally flawed, desire to improve the strength of this material, it must be possible to reduce the level of defects, improve toughness and reduce stress concentration factor inside the crack tip.
The model assumes that the fiber was pulled in the direction of stress in the concrete distribution board (spacing S), crack (radius a) present in the four walled steel fiber center, at this time, since the bond stress distribution caused by the tensile stress () produced in the vicinity of the fiber and Fused zirconia mullite the adjacent ends of the crack, the crack development plays a role constraints. If you set the internal tensile stress cracks in the ends of the stress caused by the concentration factor is, while the crack ends adjacent the bond stress distribution generated with opposite meanings, from the binding effect of the stress concentration factor, the total stress factor will be reduced
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