Mix Proportion Design And Performance Study Of Warm Mixed Asphalt Mixture

The material heating temperature of traditional hot recycled technology and the production temperature of recycled mixture is 5~15℃ higher than the ordinary hot mix asphalt,the high production temperature will lead to further aging of generative asphalt,resulting in increased fuel consumption and deterioration of construction environment.In order to prevent thermal aging of asphalt and reduce energy consumption,warm mix asphalt technology and recycled technology are combined to reduce the production temperature of the hot mix recycled asphalt so as to achieve the goals of reducing energy consumption,improving the construction environment,and reducing environmental pollution.Warm mix recycled technology has extremely far-ranging application prospect.Based on the study of aging mechanism,regeneration mechanism and warm mix mechanism of old asphalt pavement,this paper has analyzed the changes of nature of asphalt aging and described various regeneration methods and warm mix technology of old asphalt;Based on the analysis of the characteristics and applicability of various regeneration methods and warm mix technology,the types of regenerants and warm mix agent were selected in combination with the old road conditions;Then,the effects of five different regenerants on the three indicators of old asphalt,namely penetration,ductility,and softening point,are analyzed through experiments,and the amount of regenerants was determined;Then the experiments are carried on to compare the indoor performance among new asphalt;The experiment results show that the regenerants can increase the penetration,reduce the softening point,increase the ductility,and reduce the viscosity.The warm mix agent has little effect on the performance indicators of the asphalt,but it can improve the flowability of the asphalt.Through orthogonal test’s analysis on the molding process of warm mix recycled asphalt,the moulding project,which is "old material addition rate 30%+old material heating temperature 145 ℃ + medium mixing time +molding temperature 135℃",is determined.The matching design method of warm mix recycled asphalt in this paper is Marshall test design method.Through the matching design of mineral mix,the gross volume relative density,stability and flow value of warm mix recycled asphalt are measured.Through the calculation of physical indicators like void fraction and VMA and VFA,the best oil and stone ratio of warm mix recycled asphalt is determined as 4.73%.Then the varies road performance indicators of warm mix recycled asphalt are inspected,including high temperature stability,water stability,low temperature crack resistance and fatigue resistance..The data shows that it meets the road performance requirements of AC-13 C for high-grade highways.Finally,the warm mix recycled asphalt are evaluated in terms of economic benefits and social benefits.