Comparison of Properties of Bituminous Binders After Aging by Different Methods

Abstract

Introduction. The performance and durability of asphalt pavements are majorly conditioned by the quality of the bituminous binders. One of the main disadvantages of asphalt pavements is the permanent change in their properties in time due to the aging of the binder. Various laboratory methods of aging are used to predict the intensity of changes in the properties of bituminous binders that occur during the asphalt mixing at plants and the lifetime of asphalt concrete in the pavement. Problem Statement. In Ukraine, with the implementation of European principles of standardization and the transition to harmonized European standards, there is a gradual replacement of the aging method ГОСТ 18180, which has long been used in the domestic road industry, with the world-accepted RTFOT aging method. Due to the different conditions set in these methods of aging, the question of the impact of differences in aging regimes on the properties of bituminous binders, the possibility of comparing the results obtained by these two methods and the interchangeability of methods is topical. Purpose. The aim of the work is to obtain the influence of the methods of aging adopted in the road industry of Ukraine on the change of properties of road viscous bitumens and bituminous binders, modified with various additives. Materials and methods. Viscous bitumens and bituminous binders modified with various additives (adhesive additives, polymers, structuring additives) used in the domestic road industry are used as objects of research. For methods of aging the domestic method ГОСТ 18180 (for a long time this method was the only one in Ukraine used for estimation of change of properties of bituminous binders under the influence of technological temperatures and which, under test conditions, is close to the standardized method TFOT), as well as the world’s widespread RTFOT method of aging are used. Results. Based on the obtained experimental data, it is found that aging by the ГОСТ 18180 method has a slightly greater effect on the change of properties than after aging by the RTFOT method. The least sensitive indicator of aging conditions is the breaking point temperature — the difference between the values of this indicator after aging by different methods is within the convergence of the method. The conditions of the aging method have the greatest effect on the quality of bitumens modified with adhesives. The relatively short heating time of binders in accordance with the conditions of the RTFOT aging method leads to less change in the adhesion of binders to the glass surface, which may contribute to misleading in thermal stability of adhesives. Conclusions. When revising the domestic standards for technical conditions for bituminous binders, which provide for the replacement of the aging method according to GOST 18180 by the RTFOT method and setting of limits for changing the standard quality of binders after aging, should take into account the slightly lower aging intensity of RTFOT binders. This is especially true for the adhesion requirements of bitumens modified with adhesives.