Experimental Research On Triaxial Compression,Dynamic Split And Anti-penetration Properties Of UHMWPE Fiber Reinforced Concrete

Ultra high molecular weight polyethylene(UHMWPE)fiber is one of the three high technology fibers in this world,which has lots of excellent abilities.Fiber reinforced concrete using UHMWPE as strengthen material has wonderful properties like high strength and good toughness.Thus it is looked forward to improving the disadvantages of concrete,such as low tensile strength and high brittleness,which could enhance the ability of defense of penetration when applied in the area of defense engineering.During practical application,defense structures are always under complex stress-strain conditions like multiway forces and quick deformability.This causes ordinary test conclusions could not satisfy the need of engineering design,which requires aimed experimental research.Based on the above background,this paper took triaxial compression test,dynamic split test and penetration test on UHMWPE fiber reinforced concrete to research the properties of triaxial compression,dynamic split and anti-penetration,respectively.The main work and conclusions are listed as following:(1)Summarized the experimental technology and theories of triaxial compression,dynamic split and penetration.Based on that,this paper drew up the test research plans and introduced the produce technology of the specimens.(2)For the first time,researched the triaxial compression properties of UHMWPE fiber reinforced concrete.The research found that the destroy mode transforms from compression-crack into skew-shearing when adding confining pressure,while fiber couldn’t affect the destroy mode,it decrease the width of cracks apparently.Based on the existing strength criterion,compression meridian lion was analysed and fiber volume fraction was considered to get the fitting formulas.The peak strain and compression toughness increase with the increasing of fiber volume fraction,it shows that mixing fiber could increase the toughness of concrete,however,when adding confining pressure,fiber affection decrease.(3)For the first time,researched the dynamic split properties of UHMWPE fiber reinforced concrete.The research found that mixing fiber could decrease the width of cracks,delay the time of destroy and weaken the split affection.During the strain rate range of 1~20s-1,the tensile strength of fiber reinforced concrete increase significantly.Based on analysing existing formulas of dynamic increase factor(known as DIF),this paper gives the fitting formula of DIF which fits the test results well.Finally,explained the phenomenon that DIF of concrete with fiber is lower than that of concrete without fiber by using micro crack mechanism.(4)Researched the anti-penetration properties of UHMPWE fiber reinforced concrete.The research found that the destroy level extend with the increasing of bullet speed,while the fiber volume fraction could reduce the destruction of the target and the indexes of bullet crater decrease with the increasing of fiber.By comparing the existing penetration formulas with the test results,this paper gives a new penetration formula based on Hughes formula which considers the fiber volume fraction and it suits the test results well.