Introduction. The article investigates asphalt concrete mixtures made by standard technology according to [1], [2] and so-called warm asphalt concrete mixtures made at low technological temperatures on the basis of bitumen with the addition of energy-saving additives and foamed bitumen.
Problem statement. Considering the trends of the modern world, the problem arises regarding the effective use of energy resources. In conditions of increase the volumes of road works one of actual questions which arises at preparation of asphalt concrete mix, is the energy saving for its manufacturing.
The main direction in improving the technology of preparation of asphalt mixtures is to improve the adhesive properties that provide strong and stable adhesion to the pavement surface of mineral materials of different origins and adhesion between layers at low temperatures. Therefore, in the development of new technologies and methods of use of paving bitumen for the preparation of asphalt mixtures, the issue of their adhesion to the pavement surface of mineral materials has to be central. At that the adhesion means the connection or interaction (adhesion) between the surfaces of two dissimilar contact layers - bitumen and mineral material [9].
Improving the properties of bitumen under normal conditions is reached by using additional expensive surfactants, which complicate the manufacturing technology and increase the cost of asphalt concrete [9].
Improving of adhesion can be reached without use of expensive modifiers, using bitumen foaming technology, which reduces the surface tension of bitumen and thus facilitate the mixing process, promotes better coverage and uniform distribution of bitumen on the surface of mineral grains. This allows to reduce the temperature of the asphalt mixture preparation and as a result — to provide significant energy savings. The formation of thinner bitumen films on the mineral surface reduces the required volume of binder and thus reduces the cost of the asphalt mixture. Lower technological temperatures cause less thermal aging of bitumen, which in turn leads to improved quality of asphalt concrete and increased durability of pavements [9].
Purpose. The purpose of research was to study the feasibility of use of asphalt concrete mixtures made at low technological temperatures on the basis of bitumen with the addition of energy-saving additives and foamed bitumen.
Materials and methods. Experimental comparative tests of traditional hot asphalt concrete mixtures with miscellaneous content of the output, foamed bitumen and bitumen with the addition of energy-saving additives were performed.
Results. The feasibility of warm asphalt concrete mixtures use has been established. Recommendations on technological parameters of preparation, transportation, laying and compaction of such mixtures are presented.
Conclusions. Performed studies have shown that the use of warm asphalt concrete technologies can reduce the temperature of hot asphalt concrete mixtures preparing by (20–40) °C without deterioration of strength characteristics of the pavement in compare with traditional hot asphalt concrete that prepared on the same bitumen. This is reached due to the relatively new physical and chemical effects that lead to decrease in the shear resistance of the mixture during its preparation and compaction.
