Evaluation and Technical Requirements of the Initial Anti-Wear Performance of an Emulsified Asphalt Cold Recycled Mixture: A Case Study in Northern China

Abstract

Considering the initial strength evaluation method of a cold recycled asphalt emulsified mixture, the abrasion test was selected as the evaluation method. The comparison test was designed to determine the key parameters of the test, including the molding method, the curing temperature, the curing relative humidity, and the curing time. The influence of different emulsifiers, the emulsifier dosage, the asphalt dosage, the cement dosage, and the mineral aggregate gradation on the initial anti-wear performance of the mixture was analyzed. The technical requirements for the emulsified asphalt cold recycled mixture were put forward. We analyzed the significance of different influencing factors using analysis of variance. The results shows that the abrasion test is simple and reliable. It can be used to evaluate the initial abrasion resistance of the emulsified asphalt cold recycled mixture. The curing conditions had a great impact on the abrasion loss. With the increase in temperature or the extension of the curing time, the abrasion loss gradually decreased. With the increase in relative humidity, the abrasion loss gradually increased. The testing protocols, namely 25 °C with a relative humidity of 70%, the curing time was 4 h, followed an active Chinese standard (JTG/T 5521). The results indicate that the factors that affect the initial performance of the cold reclaimed mixture of emulsified asphalt are in the following order: cement dosage, cement strength grade, emulsifier type, mineral aggregate gradation, emulsified asphalt dosage, mixture moisture content, and emulsifier dosage. The cement dosage, emulsifier type, and mineral aggregate gradation had significant effects on the initial strength of the cold recycled mixture. An abrasion loss of less than 3.5% was selected as the basis for optimizing the design of the emulsified asphalt cold recycled mixture.