养生作用对硫沥青性能影响分析

Using sulfur to partially replace the conventional petroleum-based asphalt in road construction can reduce the petroleum-based asphalt and energy consumption, and promote the recycling of sulfur from waste residue, thus achieve a high economic and environmental benefit. This paper investigated the effect of sulfur dosage and curing time on the properties of sulfur extended asphalt (SEA). The differential scanning calorimeter (DSC) was used to help verify the phenomenon of sulfur recrystallization in SEA. The basic physical properties and viscosity of SEA before and after curing were analyzed, and the Dynamic Shear Rheometer (DSR) and the Bending Beam Rheometer (BBR) were applied to evaluate the rheological characteristics and fatigue performance of SEA, finally, fluorescence microscope (FM) was used to observe the sulfur distribution in SEA before and after curing. Related results indicate that the DSC curves of SEA with high sulfur content have endothermic peak and that SEA become stiffener after curing (especially with high sulfur dosage), so it is more reliable to evaluate the performance of SEA when its properties become stable after curing. Sulfur will mainly dissolve into and soften the asphalt when the sulfur dosage is low (≤10%), which enhances SEA's low-temperature performance but sacrifices its deformation resistance at high temperature to some extent. Sulfur recrystallization mainly exists in SEA with high sulfur dosage (≥35%), which hardens the asphalt and increases its deformation resistance at high temperature but leaves poor low-temperature cracking resistance. The viscosity of SEA decreases with the increase of sulfur dosage when the sulfur content is low. However, with a high dosage of sulfur, the viscosity of SEA at 90℃ and 105℃ increases with the increase of sulfur dosage while it shows little change at 120℃ and 135℃. Meanwhile, the mixing and compacting temperatures can be reduced by up to 20℃. The Linear Amplitude Sweep (LAS) test results show that the fatigue life of SEA after curing is longer than that of base asphalt, among which, the 35% SEA shows the highest fatigue life, and with the increase of sulfur dosage, the SEA fatigue life is shortened to that of base asphalt. FM analysis shows that all sulfur dissolves into the asphalt and does not recrystallize after curing when the sulfur dosage is no higher than 5%, and the corresponding SEA has no fluorescence. The distribution of sulfur in asphalt is uniform when the sulfur dosage is higher than 5%, which can ensure the performance stability of SEA. After curing, the sizes and area of sulfur crystal spots increase significantly in 10% SEA but only increase slightly for SEA with high sulfur dosages.