Study of Strength Forming Mechanism and Influencing Factors of Half-Warm Mix Asphalt

Abstract

In order to study the strength forming mechanism and influencing factors of half-warm mix asphalt (HWMA), the stability of Marshall samples is tested under different test conditions such as gradations, asphalt quantities, forming methods, number of compaction passes, maintenance period, and forms of maintenance. The results show that (1) the suspension dense gradation is satisfactory for early strength of HWMA, and its strength varies with asphalt quantity; (2) the number of compaction passes and maintenance period are two major external factors influencing strength forming, and the increase in strength reduces significantly when the number of compaction passes on both sides increases above 130. (The Marshall samples acquire final strength in 49 days of maintenance.); and (3) both loading and maintenance time significantly affect the strength forming process. Moreover, the cohesion of the material and internal friction increase, and the Marshall samples gain strength more rapidly with both the factors. Loading and maintenance time affect the internal friction and cohesion of the material, respectively. The results of this study provide guidance for design and construction of HWMA.