نوع مقاله : مقاله پژوهشی
موضوعات
عنوان مقاله English
نویسندگان English
According to previous studies and investigations, various parameters influence the moisture sensitivity and stripping of asphalt mixtures. These parameters are associated with the aggregate, asphalt, mixture design and construction, environmental conditions, and traffic. The primary objective of the present research is to evaluate stripping under different environmental and traffic conditions and to assess its counter effect on the permanent deformation of asphalt mixtures. For this study, the dynamic creep test was conducted on both conditioned and unconditioned dense-graded mixtures to compare their behaviors in the presence and absence of moisture. In this method, an axial dynamic load was applied to the saturated samples to model the dynamic entry and exit of water into their pores. The theory posits that water penetrates the interface between the aggregate and bitumen, leading to poor adhesion and reduced cohesion within the bitumen structure. This phenomenon, known as stripping, accelerates the failure rate of the asphalt mixture, resulting in permanent deformation of specimens exposed to moisture. Through the examination of various temperature and loading combinations, it was concluded that at high temperatures, an increase in frequency results in a decrease in stripping potential, whereas at low temperatures, an increase in frequency leads to an increase in stripping potential. Analyzing the mechanical characteristics of the samples revealed that the ratio of creep modulus to resilient modulus serves as an appropriate criterion for evaluating permanent deformation in the samples. This ratio allows for the investigation of stripping potential and moisture effects at elevated temperatures. Furthermore, it was found that at high temperatures, asphalt mixtures are more sensitive to temperature changes than to moisture content. A comparison of the modulus of resilience between dry and saturated samples indicated that the reduction rate of the resilience modulus in wet samples is significantly higher than that in dry samples.
کلیدواژهها English