Prospects for Evaluating the Damageability of Asphalt Concrete Pavements During Cold Recycling

Abstract

The article considers improvement of the methodology for accounting for the degradation of asphalt concrete working in the upper layers of the pavement. Development of recycling technologies for road structures is an ongoing process; it allows reaching a higher quality of reclaimed materials and using them for subsequent construction of structural layers, including the upper layers without the protective ones, as well as during repair and reconstruction of roads of various technical categories. At the same time, the system of pre-project assessment (diagnostics) of the state of asphalt concrete pavements cannot be considered optimal and effective because the determined indicators demonstrate that, firstly, various surface and structural defects are present, and, secondly, that the indicators mentioned above are more relevant to the road structure as a whole. The joint handling of the theoretical and experimental data allows concluding that damageability level depends on the physical, mechanical and structural properties, the main being maximal structural strength and the number of elastic bonds involved in the deformation process. A variant of modelling of asphalt concrete damageability depending on the work capacity is proposed, when the reduced amount of dissipated energy is replaced with sufficient accuracy for practice by the ratio of the actual number of load application cycles (freezing and thawing cycles) to the limit. A correlation between the level of damageability and the kinetics of changes of the interpore space of asphalt concrete under the influence of strain (temperature, climatic factors) has been established. Results allow fixing (predicting) the level of damageability by measuring the level of water permeability. The research methodology and equipment for implementation thereof was developed earlier, it can be effectively used at the stage of pre-project diagnosis.