Asph alt concrete pavement: technology and instructions

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

The road, made on the basis of asph alt concrete mixture, is considered one of the most profitable pavements. It is practical, inexpensive and generally allows you to provide the characteristics necessary for operation. Of course, it cannot do without drawbacks, but they, as a rule, appear in cases of non-compliance with the laying technology. On the other hand, a well-arranged asph alt concrete pavement provides a sufficiently high bearing capacity and elasticity. At the same time, there are different approaches to the creation of such roads and sites, the differences in which are determined by the composition of the mixture and laying technologies.

Asph alt mix composition

Traditional asph alt device technology provides for the presence of mineral fillers and a binder in the main composition. The first group of materials includes sand and gravel. In this case, crushed stone can be replaced with gravel, and sand is used in whole or crushed form.

Also, depending on the requirements for the coating and its operating conditions, fine mineral powder can be used. Organic component for the binder of the maincomposition is usually bitumen. The characteristics that an asph alt concrete pavement receives as a result are determined by the approach to the formation of the base mixture. Differences in the methods of making the solution are due to the parameters of the components used. For example, gravel or crushed stone can be selected with a fraction from 10 to 40 mm. So bitumen can have different viscosity and density. These and other factors ultimately determine the characteristics of the coating.

Instructions for delivering mixtures to the facility

First of all, the type, number and carrying capacity of vehicles that will carry out the delivery are determined. This choice depends on the scale of work, the volume of the mixture and the pace of future laying. The transportation process includes several stages, including weighing, loading the material, directly transporting and unloading to a receiving point. For maintenance of crushed stone, cold and hot mixtures, a dump truck with a clean body is used, which is covered with a protective awning or waterproof canopies. The cast mixtures from which the asph alt concrete pavement is formed are transported in so-called cochers. These are cars with thermoses-mixers, which provide mixing and heating of the composition during transportation. As for the transport time, in the case of hot and mastic mixtures, it depends on the characteristics of the mixture, and for cold solutions there are no restrictions on the duration of transportation.

Preparatory work

The main event in preparation for the finishinglaying the mixture is a test coating device. The length of such a strip is at least 200 m, and the width is taken in accordance with the parameters of the asph alt paver passage. Based on the test laying results, technologists determine the most suitable mixture recipe, and, if necessary, make adjustments to its laying method and compaction technology.

Test asph alt pavement is tested for characteristics such as temperature, compaction quality, substrate condition, etc. Special control technologies are used for this. In particular, non-destructive express methods and taking core samples, which are further examined in the laboratory. Based on the obtained conclusion, the technologists give recommendations for the manufacturer. If necessary, the composition of the mixture is adjusted for specific operating conditions of the coating.

Mix distribution technique

Before the distribution of the finished mass, the paving slab is installed on the edge of the beam laid before, the height of which will correspond to the thickness of the layer being laid. To prevent the mixture from spreading, a sliding type formwork is used - it must move behind the paver. If there is no such device, then even before the start of distribution in the longitudinal direction, it is necessary to fix metal strips with a length of about 20 m. In this case, the thickness of this barrier should not be less than the height of the coating being formed. By the way, the thickness of asph alt concrete pavements varies on average from 5 to 10 cm. As the mass is laid and compacted, the metal bars are removed. As for the width, most often the distribution of the mixture is carried out covering the entire carriageway.

If after the distribution of the base on the surface defects are detected, they must be processed manually. The use of rammers is practiced, which allow spot-fixing of loose seams, tubercles and other flaws. Usually, defects are formed in the areas where the strips adjoin the thrust elements - the same metal bars. Crushed stone with gravel is also poured separately. These layers of asph alt concrete pavement are formed evenly in bulk immediately after the distribution of the mixture. Next, the granular material is sunk into the base of the coating with a light roller.

Compacting technology

The compaction process must run parallel to the asph alt distributor, which distributes the mixture. Compaction is carried out continuously by a link of rollers. Also, smooth-roller, pneumatic wheel and combined special equipment can be used in the work. The force and load of compaction of cold and hot asph alt in structural layers are calculated from several indicators. In particular, technologists take into account the characteristics of the density and temperature of the mass.

Asph alt concrete pavement from a dense hot mix is made with a compaction factor of 0.99. Cold mixes assume a load with a factor of 0.96. Forfulfilling this condition, the end of the previously arranged strip is cut off with a special tool with a diamond disc.

Asph alt concrete repair instructions

Before the actual execution of repair operations, the coating is inspected. To do this, the surface is cleaned with road brushes, after which geodesic tools are used to check the evenness of the pavement. Depending on the nature of the identified defects, appropriate repair measures are applied. To further ensure the evenness of the layers, the place of cutting is marked with a rail. A bar with a level is overlapped on the coating. The place under the plank, where there is a decrease in thickness, is considered as a line for future transverse trimming. Also, the repair of asph alt concrete pavement may include operations to build up layers. Typically, such measures are used for covering the wells. Special inserts and reinforced concrete segments can be used for this.

Safety instructions

Even before the start of work, the target area must be fenced off using appropriate traffic signs. People working on the site must be in overalls established by the regulations. At night, the site must also be provided with lighting and signal lights. Separate safety measures are provided for the processes of handling solutions. So, when unloading a carrier with a mixture, it is forbidden to find people between the car and the bunker withmaterial. During laying and compaction, the asph alt concrete pavement of roads must be free from foreign objects and workers. After the completion of the events, all inventory, equipment and consumables must be removed from the coverage and delivered to the appropriate storage locations.

Coating quality control

Evaluation of the quality of the arranged coating is carried out using special tools. In particular, calibrated automated measuring instruments are used, as well as special equipment that allows deriving a complex conclusion based on the data obtained. Among the most common characteristics, on the basis of which the “performance” of asph alt concrete pavements is evaluated, there is compliance with the design parameters in terms of thickness and width, evenness of layers, slopes, temperature and quality of joints between strips.

Conclusion

Asph alt installation is a complex of technical measures. At the same time, initial design calculations are of considerable importance from the point of view of the formation of a high-quality road surface. Even with conscientious laying and compaction, the coating will not be able to perform its functions if an unsuitable mixture has been selected. Although the basic technology of asph alt concrete pavements involves the use of a standard set of components to obtain a paving mortar, their parameters may differ. Therefore, it is practiced to lay trial mixtures, which in the futuregive an idea of the most advantageous coating characteristics for a particular area. And in the future, responsibility for the quality of the road passes directly to the working team, which distributes and compacts the asph alt mass.