ABCD method for determination of low-temperature properties of ordinary and modified binders

Abstract

Introduction. The active introduction into practice of the system of volumetric and functional design (OFP) is aimed at the large-scale development by the Russian road construction industry of advanced foreign approaches to the technology of designing asphalt concrete pavements (Superpave). One of the fundamental differences between the OFP methodology and the previously established practice of evaluating technical, technological and operational indicators of road construction materials is the introduction of new methods that characterize quantitative indicators with a high degree of accuracy, based on the actual physical, chemical and mechanical properties of the components used. Thus, as methods for assessing the low-temperature properties of bitumen binders, it is proposed to use the bending beam method (BBR), which has proven itself quite well when working with traditional (ordinary) bitumen. However, the natural and climatic conditions of operation of highways in Russia clearly require the use of binders modified with high- and low-molecular compounds, including polymers. In this study, the task of applying the ABCD method to evaluate the low-temperature parameters of ordinary bitumen and polymer-bitumen binders was realized.Materials and methods. Samples of industrial batches of petroleum road viscous bitumen (GOST 33133-2014) and polymer-modified bitumen (GOST R 52056-2003) were used as objects of research. To determine the lowtemperature parameters, an ABCD 8.0 device and an air-cooled climate chamber were used. The study of bitumen binders according to the parameters laid down in the technical requirements of GOST R 58400.11–2019 ‘Automobile roads of general use. Petroleum-based bitumen binders. Method of determining the temperature of cracking using the device ABCD’ was carried out.Results. The values of the cracking temperature for ordinary and modified bitumen binders were determined. It is shown that the low-temperature parameters of polymer-bitumen binders significantly exceed similar properties of oxidized road bitumen.Discussion and conclusions. A comparative analysis of the low-temperature properties of ordinary and modified binders obtained during their determination by the direct method enables to confirm the effectiveness of the methodology developed in GOST R 58400.11-2019 for assessing the performance of binders of various component composition in difficult climatic conditions of Russia. The effectiveness of the domestic second-generation ABCD 8.0 device for direct assessment of the cracking temperature of bitumen binders of variable composition has been confirmed.