The prepared dissertation is an actual scientific study in the field of road construction by introducing a new type and technology of asphalt concrete coatings for the development of the road industry as a whole and increasing the level of road safety in Ukraine. An important scientific and practical task is solved in the dissertation work, which consists in improving such a technology as draining asphalt concrete for covering roads.
Taking into account the zoning according to the maximum intensity of torrential precipitation and the climatic conditions of the drainage asphalt concrete, it will make it possible to establish the requirements for bitumen and develop road wear designs for different categories of highways. Since the layer of draining asphalt concrete is arranged as a wear layer, the design characteristics are not established for it.
It was established that compared to dense, draining asphalt concrete at all stages (production, laying, compaction, operation) requires extremely high attention and strict requirements for crushed stone materials. supplements Therefore, all the main component materials were tested before starting the composition selection experiments.
Experimental studies of the selection of the composition of draining asphalt concrete have established that it should be performed in such a way that the compacted material has a system of connected pores to remove water from the road surface. This is achieved due to the peculiarities of the grain composition of the mixture, the main part of which is single-fraction crushed stone.
According to volumetric approaches, the main requirement is to ensure the desired void content in compacted samples. As a result, asphalt concrete mixtures with a maximum grain size of 16 mm, 11 mm and 8 mm and a bitumen content of 5.5% to 7.5% were produced. Samples should be compacted using the Marshall method.
According to the tests of materials for preparation, selection of the composition of the mixture and compliance with technologies and temperatures, the required pore content was achieved with the set minimum and maximum amounts of bituminous binder and the set process of compacting the samples.
Due to the determined indicator of the structure of draining asphalt concrete - the filling of the pores of the mineral core with bitumen, which can later be used as a condition for selecting the composition of the mixture or as parameters for evaluating the mixture after laying and compaction, it was determined that for the DAB-16 sample, the percentage of pores filled with binder , in the mineral aggregate is 28%, for DAB-11 – 34%, for DAB-8 – 39% (with a minimum content of bituminous binder), which indicates the achievement of sufficient drainage capacity of draining asphalt concrete with optimal residual porosity. To fully understand the performance of draining asphalt concrete, the indicator of vertical and horizontal permeability was determined. The permeability values obtained as a result of the conducted research are more than enough to divert water in the most saturated month in terms of the maximum amount of heavy rainfall, or peak short-term downpours to successfully increase the safe operational characteristics of highways.
On the basis of technical and economic calculations, the expediency of using the technology of arranging covers from draining asphalt concrete has been confirmed. Taking into account that draining asphalt concrete is a special type of asphalt concrete, and therefore, of course, requires special attention at all stages and certain technically complex approaches to itself, but in comparison with SHMA, due to certain important economic factors such as materials (grain composition) (up to 10% ), the cost of the mixture (up to 6%), the consumption of material for installation (up to 30%), an increase in operational characteristics, which will lead to a beneficial reduction of socio-economic losses from a reduction in traffic accidents, and most importantly - to a decrease in fatalities due to road accidents , during the implementation of DAB technology in Ukraine, there is an opportunity to cover the costs associated with the need for special winter maintenance and measures to clean the pores, which may become clogged during the years of operation.
Keywords: highways, road pavement, road surface, asphalt concrete mixture, wear layer, draining asphalt concrete, open porous, porosity, permeability.
