Experimental study on tensile mechanical properties of mine fiber reinforced desert sand concrete
Concrete plays an important role in controlling the deformation of surrounding rock in underground mine tunnels as a key component of modern anchor net spraying combined support.To address the practical issues of high cost and susceptibility to cracking under tensile stress of traditional mine concrete,a new type of mine fiber reinforced desert sand concrete has been developed,which uses desert sand as fine aggregate and polyvinyl alcohol(PVA)fibers as reinforcement material.In order to verify the mechanical properties of the new supporting material,36 dog bone specimens with the size of 330 mm×60 mm×13 mm are prepared by selecting the particle size of desert sand,water-binder ratio,fiber length and fiber dosage as the variable,and their effects on the elastic modulus,tensile strength and ultimate tensile strain of concrete are discussed.The results show that the tensile elastic modulus and ultimate tensile strain of the material are increased by replacing ordinary river sand with desert sand,reaching 3.70 MPa and 4.01%,respectively,and the excellent properties of Xinjiang desert sand are fully utilized,which provides a more economical and effective choice for roadway support and other projects.The incorporation of domestic PVA fiber can effectively enhance the tensile strength and deformation capacity of desert sand concrete.Compared with river sand,desert sand has a smaller particle size and smooth surface makes it more evenly distributed in the matrix,which can improve the ability of concrete to resist cracks,and the synergy between desert sand and PVA fiber is also more effective,and the fiber can better slip and resist the development of cracks.Desert sand is a medium and fine sand,which can interact well with other raw materials.Considering the abundant desert sand resources in the western mining area,the research and development of mining fiber reinforced desert sand concrete has certain application prospects in the field of roadway support in the western desert mining area.
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