Analysis of factors affecting water stability of foam warm mix asphalt mixture

(Guangdong Communication Planning & Design Institute Group Co., Ltd., Guangzhou 510507)

Abstract

water stability of warm mix asphalt mixture based on foamed asphalt is the key evaluation index affecting its road performance. The moisture content in the production process of foamed asphalt is unfavorable to the water stability of warm mix asphalt mixture. In order to improve its water stability, through immersion Marshall test and freeze-thaw splitting test, taking foaming effect, asphalt temperature, foaming water consumption and polymer fiber content as influencing factors, the control variable method is used to study and analyze the influence of factors on the water stability of warm mix asphalt mixture. The test results show that the foaming effect of asphalt, asphalt temperature, foaming water consumption and fiber content are the direct factors affecting the water stability of warm mix asphalt mixture. According to the importance analysis of random forest variables, foaming water consumption, foaming effect and asphalt temperature are the most important variables, while fiber content is the least. Taking the asphalt used in this paper as an example, it is suggested to improve the water stability of warm mix asphalt mixture with the combination of the best foaming effect, asphalt temperature 155 °C, foaming water consumption 2% and fiber content 0.3%.