Emulsified asphalt cold recycled mixture is commonly used in the upper base course of expressway reconstruction asphalt pavement. When the following layer is paved with hot-mix asphalt (HMA) mixture, the aging asphalt in the recycled material is activated due to the temperature conduction effect of the HMA mixture, so that the cold recycled layer produces "secondary thermal compaction" under the action of a roller. Based on this phenomenon, the present study aimed to discuss the influence of different molding methods and mixing processes on the volume parameters and mechanical properties of cold recycled emulsified asphalt mixture. The influences of Marshall compaction times, gyratory compaction times, curing time, and specimen-forming temperature on the voids and splitting strength of cold recycled mixture were studied. The field core sample was compared with the laboratory-forming method, which accords with the field compaction condition of the cold recycled upper base. first-time compaction number of large Marshall is 150 times and secondary compaction number is 75 times (Shorthand for 150 + 75), the compaction times of the gyratory specimen is "30 + 15." The curing time of the cold recycled mixture should not exceed 3 h and should not be constructed in low-temperature weather to ensure the quality of pavement construction. The use of a new stage and step laboratory mixing process simulating the plant mixing, compared with the traditional mixing process, increases the splitting strength by at least 13%.
Abstract-To explore the variation of hot mix plant recycling mixture design parameters and quality under the influence of RAP performance, represent index and factor level of RAP performance were determined, the variation of mix proportion design parameters was comprehensively analysised under different indexes and levels based on orthogonal test, and then the pavement performance was studyed. The result showed that: the fineness modulus of RAP had the most significant effect on design parameters, and then followed by asphalt content and aging degree. The aging degree of RAP had the most significant effect on mechanical properties of regeneration mixture. The high temperature properties were improved by a certain degree with a high aging degree, but then the water stability decreased significantly. And the high temperature properties of regeneration mixture decreased as the increasing of fineness modulus of RAP.
Abstract. Recommended dosage and type of warm mix agent widely used at present were investigated in order to determine the technical performance of warm-mixed asphalt and its mixture. The warm-mix agent's effect on asphalt performance were analyzed based on the three major indexes experiments of asphalt, and the road performance of the asphalt mixture is evaluated by high and low temperature test and water stability test. The results showed that the majority of warm-mix agent products can improve the high temperature performance of asphalt, and deteriorate the low temperature performance; the majority of warm-mix agent can cause decline in the low temperature performance, but have little impact on other indexes. The new product development should be aim at existing problems for improving design.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.