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为探究纳米氧化锌改性沥青混合料的路用性能,首先应用高速剪切法制备1%、2%、3%、4%、5%、6%、7%七种剂量纳米氧化锌改性沥青,通过基质沥青与7种改性沥青基本性能的对比分析,优选出1%、4%、7%三种剂量纳米氧化锌改性沥青进行DSR试验、BBR试验和布洛克菲尔德黏度计法试验,分析纳米氧化锌改性沥青路用性能。其次,通过车辙试验、浸水马歇尔试验、冻融劈裂试验和低温弯曲试验系统分析沥青混合料的路用性能,并应用红外光谱法从微观角度分析其改性机理。结果表明:1%、4%、7%三种剂量的纳米氧化锌改性沥青均能有效改善沥青的高温、低温、黏度及抗疲劳性能,最佳掺量为4%;4%剂量纳米氧化锌改性沥青混合料的高温稳定性、水稳定性和低温抗裂性能最佳;采用高速剪切法制备纳米氧化锌改性沥青能够充分发挥纳米粒子的特性,能够与基质沥青发生物理化学反应,形成稳定的改性沥青体系,提高基质沥青的软化点和稠度;在高速剪切作用下,熔融的基质沥青化学键断裂并与纳米粒子表面的羟基发生化学反应,形成纳米粒子基质沥青共熔体系。
In order to explore the road performance of nano-sized zinc oxide modified asphalt mixture, firstly, the high-speed shearing method was used to prepare nano zinc oxide with the dosage of 1%, 2%, 3%, 4%, 5%, 6% and 7% Asphalt, DSR test, BBR test and Brookfield viscometer test were conducted to compare the basic properties of matrix asphalt and seven kinds of modified asphalt with 1%, 4% and 7% Analysis of road performance of nano zinc oxide modified asphalt. Secondly, the road performance of asphalt mixture was analyzed by rutting test, immersion Marshall test, freeze-thaw splitting test and low temperature bending test. The modification mechanism of the asphalt mixture was analyzed by infrared spectroscopy. The results showed that 1%, 4% and 7% of nano-sized zinc oxide modified asphalt can effectively improve the high temperature, low temperature, viscosity and fatigue resistance of asphalt, the best dosage is 4%; 4% Zinc modified asphalt mixture has the best high temperature stability, water stability and low temperature anti-cracking performance. The preparation of nano zinc oxide modified asphalt by high speed shearing can give full play to the characteristics of nano-particles and can react with matrix asphalt physically and chemically To form a stable modified asphalt system and improve the softening point and consistency of the matrix asphalt. Under high shear, the chemical bond of the melted matrix asphalt breaks down and chemically reacts with hydroxyl groups on the surface of the nanoparticles to form a nano-particle matrix asphaltene eutectic system .