Research On Impact Resistance Of ECC Crash Barrier Material

With the rapid development of China's transportation industry,the number of motor vehicles increases year by year,the resulting traffic safety problem is more and more serious,and the safety problem of crash barrier can not be ignored.Engineered Cementitious Composite(ECC),a high performance fiber reinforced cement based composite,has excellent mechanical properties and has the potential to overcome the limitations of traditional crash barrier.It can be used as a new type of crash barrier material.At present,the PVA fiber of domestic and foreign ECC materials is mostly from Japan Kuraray company and its price is very high.Although the price of domestic PVA fiber is low,the technical characteristics are different from those of Kuraray PVA fiber.Direct substitution usually leads to a loss of mechanical performance of ECC.Therefore,it is necessary to study the mechanical properties and impact resistance of domestic ECC to explore its feasibility as a new crash barrier material.Firstly,based on the existing research results of domestic ECC,the compressive performance,bending resistance and tensile properties of two kinds of domestic ECC materials with optimized ratio were studied.The results show that both domestic ECC have excellent mechanical properties to meet the requirements of crash barrier materials.Secondly,the tensile properties of two kinds of domestic ECC at different tensile loading rates were studied,and the tensile cracking patterns were observed and analyzed.The results show that the two kinds of domestic ECC show a larger reduction of ductility with the increase of the tensile rate,but at high tensile rates it can still maintain tensile ductility.The tensile ductility was found to be retained even after exposure to freeze-thaw cycles under cold weather conditions.Finally,the impact resistance of two kinds of domestic ECC was investigated by drop hammer impact test equipped with acceleration sensors.The results show that both domestic ECC have good impact resistance.Its ultra-high ductility can absorb more collision energy and reduce the harm to the drivers and passengers.In addition,under the multiple impacts,ECC maintained stable impact energy absorption before failure by formation of large cracks.As a result,the maintenance cost of domestic ECC crash barrier is expected to be limited.