玄武岩纤维与布顿岩沥青复合改性沥青混合料性能及改性机理

Study on Performance and Modification Mechanism of Basalt Fiber and Burton Rock Asphalt Compound Modified Asphalt Mixture

提高单一纤维和天然沥青改性沥青混合料的综合路用性能一直是工程界和学术界关注的热点。基于板带拉伸试验、BBR和DSR试验优化出了适宜的BRA与BF掺量范围,采用室内马歇尔、车辙、低温弯曲、浸水马歇尔、冻融劈裂、及四分点加载疲劳试验研究了BF/BRA复合改性沥青混合料的路用性能和抗疲劳性能。结果表明,将BRA与玄武岩纤维复配后可实现二者对BRA/BF复合改性沥青高温性能改善效果的叠加作用,BRA对玄武岩改性沥青低温性能有不利影响;掺加BF/BRA复合改性剂极大提高了沥青混合料的高温抗车辙性能,0.2%BF+25%BRA、0.3%BF+20%BRA、0.4%BF+15%BRA三种复合改性混合料的弯曲应变可达到3 000με以上,BRA/BF复合改性沥青混合料抗水损害性能优良。BRA/BF复合改性沥青混合料疲劳优于SBS改性沥青混合料,且疲劳寿命对应变水平的敏感性小于SBS改性沥青混合料。玄武岩纤维对沥青混合料疲劳性能的改善机理在于其"加筋阻裂作用"、"吸附稳定作用"、"界面增强作用"、"传力、消散力作用"及"加箍锁作用",有效延缓了加载过程中微裂缝的发生和发展。

Improving the comprehensive performance of single fiber and natural asphalt modified asphalt mixture has been a hot topic in engineering and academia. Based on the strip tensile test,BBR and DSR tests,the suitable ranges of BRA and BF contents were optimized. By using Marshall,rutting,low temperature bending,immersion Marshall,freeze-thaw splitting and quadrature point loading fatigue tests/BRA Composite Modified Asphalt Mixture. The results show that BRA and basalt fiber can be used to improve the high-temperature performance of BRA/BF composite modified asphalt. BRA has a negative effect on the low-temperature performance of basalt modified asphalt. The blending of BF/BRA The flexural strain of 0. 2% BF + 25% BRA,0. 3% BF + 20% BRA,0. 4% BF + 15% BRA could reach the highest value of the flexural strength of the asphalt mixture. 3000με or more,BRA/BF composite modified asphalt mixture excellent resistance to water damage. BRA/BF composite modified asphalt mixture is better than SBS modified asphalt mixture,and the fatigue life is less sensitive to strain level than SBS modified asphalt mixture. The mechanism of the improvement of the basalt fiber on the fatigue performance of asphalt mixture is its effective role in strengthening the crack resistance,adsorption stabilization,interface strengthening,force transfer,dissipative force,and hoop lock. And retarding theoccurrence and development of micro-cracks in the loading process. BRA modified the asphalt mixture to improve the adhesion between asphalt mortar and aggregates and the stiffness modulus of asphalt mixture