含纳米二氧化硅的聚乙烯改性沥青混合料疲劳和力学性能研究

Research on Fatigue and Mechanical Properties of Polyethylene Modified Asphalt Mixture Containing Nano-Silica

【目的】通过制备不同纳米二氧化硅掺量的复合改性沥青来研究纳米二氧化硅对聚乙烯改性沥青混合料性能的影响。【方法】通过四点弯曲疲劳试验、劲度模量试验、间接拉伸强度试验来分析纳米二氧化硅复合改性沥青混合料的性能。【结果】试验结果表明:当纳米二氧化硅掺量从1%增加到4%时,混合料的疲劳寿命、劲度模量和间接拉伸强度先增大后减小;当纳米二氧化硅掺量为3%时,混合料在20℃和30℃时的疲劳性能均最优;当纳米二氧化硅掺量为2%时,劲度模量和间接拉伸强度最优,且短期老化后的间接拉伸强度降幅最小。【结论】综合考虑各项性能指标,纳米二氧化硅的最佳掺量为2%~3%,此时复合改性沥青混合料疲劳和力学性能可提高40%以上。

[Purposes]The effect of nano-silica on the performance of polyethylene modified asphalt mix-ture was studied by preparing composite modified asphalt with different nano-silica content.[Methods]The performance of nano-silica composite modified asphalt mixture was analyzed by four-point bending fatigue test,stiffness modulus test and indirect tensile strength test.[Findings]The test results showed that when the content of nano-silica increased from 1%to 4%,the fatigue life,stiffness modulus and in-direct tensile strength of the mixture increased first and then decreased.When the content of nano-silica is 3%,the fatigue performance of the mixture is optimal at 20°C and 30°C.When the content of nano-silica is 2%,the stiffness modulus and indirect tensile strength are the best,and the decrease of indirect tensile strength after short-term aging is the smallest.[Conclusions]Based on the comprehensive perfor-mance indicators,the optimum content of nano-silica is 2%~3%,and the fatigue and mechanical proper-ties of the composite modified asphalt mixture can be increased by more than 40%.