Wang studied the fatigue performance of a high-modulus asphalt mixture and determined that the inorganic modifier calcium sulfate crystal improved the fatigue resistance of HMAC. Considering that high-modulus admixture may reduce the performance of asphalt concrete, Cheng examined the effects of different types of admixtures on the cracking resistance of HMAC and concluded that a mineral fiber admixture could effectively improve the cracking resistance of asphalt concrete.
used SBS-modified asphalt and an antirutting agent for compound modification of asphalt concrete and similar conclusions were obtained. They reported that the high-temperature performances of asphalt and asphalt mixture improved after adding a high-modulus agent, but their low-temperature performances slightly decreased. added two types of high-modulus agents to 70# asphalt and SBS-modified asphalt and studied the performance of modified asphalt and asphalt mixture. Because HMAC has excellent high-temperature rutting resistance, the investigation on the performance of HMAC has become popular with researchers. In recent years, in South China, rutting has become one of the most common distresses of asphalt pavement in high temperature and heavy traffic areas. Generally, there are three methods to obtain high-modulus binders that increases the stiffness of asphalt concrete: (1) using hard-grade asphalt binders that have low penetration and high softening points (2) using a polymer modifier, such as styrene-butadiene-styrene (SBS) and lake asphalt and (3) using a high-modulus agent. The selection of high-modulus asphalt is extremely important to the production of HMAC. Due to these benefits, HMAC is gradually used in the joint and surface layers. Practically, researchers determined that HMAC has excellent high-temperature rutting resistance, fatigue resistance, and water stability. When the complex modulus was larger than 14000 MPa at 15☌ and 10 Hz, the asphalt concrete can be called HMAC. To improve the strength of asphalt pavement and reduce its thickness, France was the first country to adopt high-modulus asphalt concrete (HMAC). Based on the results of the infrared spectrum test, it can be concluded that a high-modulus agent changes the asphalt matrix via physical blending modification. Fluorescence microscopy shows that the high-modulus agent particles can swell in the asphalt to form polymer links that improve the viscoelastic properties of the asphalt. The dynamic modulus test further demonstrates that the high-modulus modified asphalt mixture exhibits superior performance in high-temperature range. Furthermore, the results of the rutting test show that the high-modulus modified asphalt mixture has better resistance to deformation than the SBS-modified asphalt mixture. When the dosage increases to 6.67%, the modification effect is better than that of the SBS-modified asphalt.
The results demonstrate that the high-modulus agent improves the high-temperature performance and viscoelastic properties of the matrix asphalt.
Based on rutting and dynamic modulus tests, the differences of road performances between high-modulus modified asphalt mixture and SBS-modified asphalt mixture were compared. Moreover, the modification mechanism of the high-modulus agent was examined using fluorescence microscopy and infrared spectrum test. The effects of high-modulus agent on the viscoelastic properties of asphalt with different dosages were quantified via rheological tests as compared to base binder and styrene-butadiene-styrene- (SBS-) modified asphalt. The objective of this study is to investigate the performance and modification mechanism of high-modulus asphalt. Therefore, one high-modulus agent was used in this study to prepare high-modulus asphalt binder with different dosages. High-modulus asphalt concrete (HMAC) is considered as an effective paving material for addressing the increasing heavy traffic and rutting problems.
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