Asphalt is an integral part of modern cities and rural areas. As a rule, well-laid asphalt lasts up to 10 years, subject to the optimal operating conditions.
Preliminary work
The first stage is the marking of the territory: specialists determine where they will lay asphalt, where to put curbs, and where to collect and drain rainwater. They also determine the composition of the asphalt concrete pavement, the thickness of the crushed stone base. A thickness of 10-15 cm is sufficient in an area where mainly pedestrians move and where passenger transport does not often pass. If an industrial territory, a gas station, a section of a road is being developed, i.e. regular traffic, including trucks, is expected, then a 25-35 cm crushed stone base and two or three layers of asphalt are required.
Crushed stone is selected with a suitable fraction. Fraction is the size of an individual stone / grain, which is the maximum allowable in each case. If the desired thickness of the crushed stone base is 10-15 cm, then crushed stone of 20-40 cm fraction is used. If the base should be wider and more reliable, it is laid in two or three layers. When laying the bottom layer of the base, crushed stone should have a fraction of 40-70 cm, this layer in a situation of rising groundwater is responsible for water drainage. The second layer provides an even distribution of the load on the base, for it they take 20-40 cm crushed stone. Crushed stone of 5-20 cm fraction is used for the third layer. Each layer is compacted with a roller in 5-6 passes. The slope on the territory (5-10 mm per 1 meter) is set in the direction where the installation of rainwater collection is planned.
Installation of curbs, rainwater drainage, installation of hatches, construction and repair of drainage and sewerage wells are carried out before the laying of asphalt.
Asphalting
It is recommended to lay asphalt in the absence of rain and at an air temperature of at least 10 ° C so that the mixture does not cool down. If, for some reason, laying is carried out in winter, an “iron” must first be passed through the territory - a special machine that will dry and heat the base.
Dump trucks deliver ready-made asphalt concrete mixture to the site. Asphalt pavers spread it across the area, while rollers, rammers and vibratory plates compact it.
The asphalt must be laid so that it is level with the surrounding surface. Its thickness depends on the planned operating conditions. For example, in the adjoining territories of residential high-rise buildings, an asphalt layer of about 4-5 cm is appropriate. If intensive exploitation of the territory is planned, the movement of trucks, etc., asphalt should be laid in two layers - from coarse-grained and fine-grained asphalt concrete, each layer by 4-5 cm. For the best coating strength, a third layer can be applied.
To ensure adhesion of the lower layer of asphalt with the upper, old and new layers, a binder is used - bitumen. It is poured over the laid asphalt layer before the new one is laid.
The pavement is leveled with special machines - road rollers and vibratory plate. Rollers weighing 6-10 tons or more are used to compact the base and asphalt concrete pavement, which is designed for heavy loads. Rollers weighing 2-4 tons are used for compacting asphalt, designed for moderate loads. In hard-to-reach places, vibratory plates and vibratory rammers are used. To make the compaction better, the base is moistened using sprinklers.
