Effects of thermal degradation on polymer modified asphalt binders during storage and transportation

Currently, more and more polymer modified asphalt binders (PMA) were used in road engineering in China. There are still many unqualified phenomena in the test of PMA samples on the construction site, which causes a confusion of suppler. To obtain the high quality of asphalt pavement, the effects of thermal degradation on PMA during storage and transportation become very important. This paper investigates physical properties and molecular structure of PMA samples by a series of test. The results of conventional tests indicated that time, temperature and oxygen concentration (thermal degradation test in thin air (TDTTA) and TFOT) have great effects on the deterioration of asphalt performance. For TDTTA or TFOT, the PMA exhibit performance erosion with time increasing. Moreover, the influences of temperature on physical properties of three PMA can be ranked as follows:163 degrees C> 150 degrees C> 130 degrees C. Compared with the effects of TDTTA on physical properties of three PMA, the TFOT has a more significant effect on physical properties of three PMA. The reason is that many scholars main focus on the study of conditions of high oxygen concentrated. Moreover, fourier transform infrared spectroscopy (FTIR) displayed that there were no chemical reaction found in three PMA. For TDTTA or TFOT, the degradation reaction of polymer in three PMA can clearly present base on analysis results of gel permeation chromatography (GPC) and FTIR. The performance erosion of PMA is more obvious in the air/oxygen compared with performance erosion of PMA in the thin air/oxygen, but the performance degradation cannot be ignored when the air/oxygen is lack during the process of practical applications. (C) 2020 Elsevier Ltd. All rights reserved.