In order to lack of space, the usage of underground structures for passive defense are expanded. Therefore the selection of materials in consideration of economic and safety is necessary concrete and shotcrete are used extensively in underground structures.In addition, shotcrete has been used extensively in most part of the world for wide variety of applications including new stabilization, as retaining walls for large excavations, and for tunel lining, etc. concrete and shotcrete are brittle materials, hence reinforcement of them to achieve hugh ductility is very important . addition of stel bars and steel mesh aids to converting the bittle characteristics to a ductile one. But in long-term in humid condition steel is rusted that lead to cretion a osteoporosis concrete and shotcrete, so it is necessary to replace other artificial materials instead of steel. In addition in steel-mesh applications, installation of steel mesh (SM) can be difficult, time consuming, hazardous and expensive. Also lining quality can be poor, i.e., no uniform bond between shotcrete and rock, forming low-quality shadow areas behind the wire and badly placed reinforcement due to irregular mesh positions, etc. by contrast, fibers eliminate the need for conventional concrete reinforcing steel , welded wire mesh or the chain-link mesh , and this alone results in a significant enhancement of the ease of shotcrete placement. In addition, fibers imart toughness or energy absorption capability to hardended shotcrete , resulting in improved deformability. In this research for reinforcement of concrete and shotcrete we use barchip fiber, advantages include no rusty, a reduction of cracking, and enhancements to ductilily, impact resistance, and toughness . in addition reduced fire damage , along with economic benefits of reduced placement labor and overall savings in reinforcement costs.in this research the effect of barchip fiber on ductility behavior of concrete and shotcrete are studied. Results has shown that barchip fiber have significant effect on shear strength, tensile strength. Adhesion strength and ductility behavior of concrte and shotcrete, in addition barchip fiber increase friction angel, but reduced compression strength.the results of direct shear test show that with increase fiber, the increase of shear strength in concrete and shotcrete is up to 12%. In addition adhesion strength and friction angel also increase up to10% and 11% for concrete and 5% and 14% for shotcrete . in research tensile strength of concrte and shotcrete that reinforced with barchip fiber, is defined with brazillian test. The results show that with increase fiber , the incresase of tensile streneght is up to 25% rather than plaine concret and shotcrete.
