硅烷偶联剂/硅藻土复合改性片麻岩沥青混合料路用性能评价

刘鹏飞; 常明丰; 朱晨旭; 熊锐; 张艺行

硅烷偶联剂/硅藻土复合改性片麻岩沥青混合料路用性能评价

Road performance evaluation of the silane coupling agent/diatomite composite modified gneiss asphalt mixture

摘要

摘要: 为提升片麻岩集料与沥青黏附性及其沥青混合料路用性能，采用硅烷偶联剂KH550和硅藻土对片麻岩沥青混合料进行复合改性，阐释硅烷偶联剂/硅藻土复合改性机理。利用马歇尔试验和冻融劈裂试验指标，结合正交试验确定KH550/硅藻土复合改性片麻岩沥青混合料中KH550、硅藻土的最佳掺量及最佳油石比，并通过动态模量试验、半圆弯曲试验、冻融劈裂试验评价其路用性能。结果表明：通过正交试验确定三因素最优水平组合为KH550(0.9%)、硅藻土(7.5%)、油石比(5.8%)；20℃、35℃和50℃时，相同频率下KH-DM的动态模量最大，以50℃、10 Hz为例，与SCRM相比，KHM、DM和KH-DM的动态模量分别增大了26.7%、50.8%和73.3%，相位角的变化趋势基本与动态模量相反；相较于SCRM，−20℃时DM、KHM、KH-DM的断裂能分别增加了2.52%、5.88%、45.59%，断裂韧性随温度降低而增大，−20℃、−10℃、0℃的开裂阻力指数CRI(Crack Resistance Index)最小增幅分别为0.35%、6.62%、41.74%；SCRM的冻融劈裂强度比最小，KH-DM、DM、KHM分别提高了10.5%、3.1%、7.2%。KH550和硅藻土复合改性显著提升了沥青混合料的路用性能，且复合改性优于单一改性。研究成果为硅烷偶联剂和硅藻土复合改性用于中酸性源地集料区道路工程提供技术参考。

Abstract: To improve the adhesion between gneiss aggregate and asphalt, as well as the road performance of gneiss asphalt mixture, the silane coupling agent KH550 and diatomite were used for the composite modification of gneiss asphalt mixture, and the composite modification mechanism of silane coupling agent and diatomite was explained. The Marshall test and freeze-thaw splitting test indicators were used, combining the orthogonal test, to determine the optimal content of KH550 and diatomite and asphalt-aggregate ratio in the KH550/ diatomite composite modified gneiss asphalt mixture. The road performance was evaluated through the dynamic modulus test, semi-circular bending test and freeze-thaw splitting test. The results show that the optimal combination of three factors determined through the orthogonal test is KH550(0.9%), diatomite(7.5%) and asphalt-aggregate ratio (5.8%). At 20℃, 35℃, and 50℃, KH-DM has the largest dynamic modulus at the same frequency. Taking 50℃ and 10 Hz as an example, compared to SCRM, the dynamic moduli of KHM, DM, and KH-DM increase by 26.7%, 50.8%, and 73.3%, respectively. And the change trend of phase angle is basically opposite to that of the dynamic modulus. The fracture energies of DM, KHM, and KH-DM increase by 2.52%, 5.88% and 45.59%, respectively at −20℃, compared to SCRM. The fracture toughness increases with the decrease of temperature. Additionally, the minimum increases in the crack resistance index (CRI) are 0.35%, 6.62% and 41.74%, respectively at −20℃, −10℃ and 0℃. The freeze-thaw splitting strength ratio of SCRM is the smallest, those of KH-DM, DM, and KHM increase by 10.5%, 3.1% and 7.2%, respectively. The composite modification of KH550 and diatomite significantly improves the road performance of gneiss asphalt mixture, and the composite modification is superior to the single modification. The research results provide the technical reference from the composite modification of silane coupling agent and diatomite for road engineering in neutral and acidic source aggregate areas.

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