Compacting asphalt – how and with what to compact asphalt

Asphalt compaction work plays a critical role in creating a long-lasting, durable and wear-resistant road surface (and can even sometimes determine the success or failure of a particular project), although its cost may only be a small part of the overall cost. The ultimate goal of compaction is to form an asphalt concrete structure that is resistant to external influences.

The result is influenced by a whole range of factors, including ambient temperature, thickness of the compacted layer and physical and mechanical properties of the mixture components. Considering that a decrease in the temperature of the mixture leads to a sharp increase in the compressive strength, each stage of compaction must be performed in a certain temperature range. In addition to the ambient temperature, the cooling rate of the mixture also depends on the thickness of the laid layer, the size and shape of the crushed stone, as well as on the added additives, which are now widely used. The roller operator's task remains the same. In the short allotted period of time from laying the hot mixture, it must achieve a given degree of compaction and smoothness with a minimum number of flaws with clear interaction with the rest of the equipment. True, a modern operator, unlike his counterpart in, say, the 1960s, must ensure that the maximum possible remains in the past.

In the 1970s Vibrating machines began to be used to compact asphalt concrete mixtures, and it is this type that is now most widely used. The vibration mechanism is located inside the drum and consists of a rotating eccentric load, which adds a dynamic load to the static one. Compression waves are transmitted from the surface to the lower layers of laid asphalt and set their particles in motion. In this way, internal friction is reduced, particles are “repacked,” density is increased, and voids are filled. Increasing the number of points of contact between particles also leads to increased stability and strength of the coating. Vibratory compaction achieves higher densities and greater depth effects than static compaction, and complete compaction is achieved in fewer passes. The vibration can be easily turned off if it is not needed, which is not often the case, but the first pass behind the paver should always be made with the vibration on.

The key characteristics of the vibrating drum, the main working part of the roller, are its width, diameter, as well as the frequency and amplitude of vibrations. The number of passes depends on the width, and the size of the overlap of stripes must be taken into account in the calculation. The split roller design allows its two halves to rotate at different speeds. This reduces movement of the asphalt concrete surface when working on sharp turns and ensures a smooth compacted surface. If the roller is equipped with conventional rollers, the operator must follow common cornering practices to ensure proper quality.

The influence of frequency and amplitude on compaction has been a subject of debate since the advent of vibration technology. A frequency in the range of 40–50 Hz (from 2400 to 3000 vibrations per minute) was previously considered optimal, but in the late 1990s. some manufacturers began to offer machines with increased frequencies, up to 70 Hz, citing an increase in productivity. The roller speed is selected taking into account the drum diameter and vibration frequency, so this approach can be considered justified. For example, Volvo offers a high-frequency, high-amplitude 13.8-tonne DD140 roller with a 2135 mm wide drum with a vibration frequency of up to 66.7 Hz and an amplitude of up to 0.88 mm. Features of this machine include eccentric rotation, which automatically adjusts to the direction of travel, and a patented impact pitch meter, which serves as a visual reference for the operator to control speed and maintain a high smoothness of the control surface.

Taking into account the design features of the eccentric vibration mechanism, as the vibration frequency increases, the amplitude should be reduced, since due to increased loads there is a risk of bearing destruction. All medium and heavy tandem rollers have a choice of low or high amplitude, which is used for thin and thick paving layers respectively. Although it is believed that in most cases two amplitudes and two frequencies are enough, some manufacturers increase the amplitude range on their machines to 4, 5 or even 8 values, while others offer stepless frequency adjustment. The use of new materials, such as ShMA (crushed stone mastic asphalt concrete) and compositions using SuperPave technology, requires not only finer tuning of the resulting forces to minimize the destruction of the filler, but also precise control of the temperature of the compacted surface. To achieve this, manufacturers install infrared sensors that allow the operator to monitor the process.

The evolution of the road roller follows the growing demands in the road industry. If the hydrostatic drive of the travel and vibration mechanism is accepted by most manufacturers as a standard (mechanically driven rollers are still produced, perhaps, only in China), then the design of the working body is subject to serious changes. The traditional method of compaction using vibration is increasingly complemented by oscillation. The circular path of the eccentric, which rotates inside a conventional vibratory drum, is good for generating large centrifugal forces. If, after a certain number of passes of the roller, the material is already sufficiently compacted, then further impacts lead to the destruction of the grains of the material of the compacted layer.

Compaction with oscillation occurs in a completely different way. Here, loads rotating in one direction create a moment of force relative to the axis of the roller, which causes oscillating movements of the roller horizontally. The resulting shear forces, directed forward and backward, are transferred to the layer. But the oscillatory loads that develop in this case are an order of magnitude smaller compared to the same forces during vibration. In addition, the roller remains in constant contact with the surface. The continuous load resulting from this contact also promotes rapid and uniform compaction. Overall, this method is extremely efficient and safe for the layer material due to less vibration of both the material being compacted and the machine itself. During oscillation, the amplitude of the oscillations “adjusts” to the stiffness of the material. At the same time, the oscillation system, developed by one of the market leaders, the German company Hamm, is not based on complex mechanical control systems, but uses a simple physical relationship: the amplitude continuously decreases with increasing rigidity of the material being compacted. In addition, the oscillating movements of the material particles ensure their uniform mixing with bitumen while maintaining a high surface roughness. This guarantees reliable initial adhesion of car wheels and accordingly increases traffic safety.

Another difference between modern models and previous analogues is the use of automatic systems, which significantly simplify the operator’s work and are designed to minimize the influence of the human factor. Among the simplest solutions is the automatic activation and deactivation of vibration associated with the speed of the roller. This function prevents the vibration mechanism from operating when the roller is not moving, which could lead to machine failure. Automatic setting of the interval between impacts of the vibration mechanism allows you to set a certain number of impacts for each meter of laying. This optimizes performance and reduces the risk of loss of smoothness. Automatic frequency selection is associated with amplitude selection - the frequency is always higher at low amplitude and lower at high amplitude. Delaying the activation of the rear drum vibration mechanism for several seconds ensures stable engine operation under increasing load. Automatic speed limiting prevents the formation of depressions that can occur when the roller moves too quickly with the vibration mechanism engaged. Automatic activation of the irrigation system eliminates its operation when the skating rink is stopped, and also regulates the water supply depending on the speed of the skating rink.

Different manufacturers are implementing their own systems, which become their competitive advantage. Bomag (Germany) is considered the world leader in the compaction equipment market. The company was founded in 1957 and has 2,000 employees worldwide. Bomag is the only manufacturer that uses all existing types of vibration systems in its rollers. This is a standard system with 2 frequencies and 2 amplitudes, a system with tangential oscillation (Bomag TanGO) and a directional vibration system with a variable vector of oscillation direction (Bomag Asphalt Manager). The latter system not only allows compaction monitoring, but also dynamically influences the process itself. The dynamic stiffness value is determined with each pass by testing the material to be compacted. The vibrating roller itself is used as a measuring tool. The direction of vibration changes gradually from vertical, directed deep into the layer, to horizontal, surface compaction, depending on the rigidity of the material. The roller operator can also select manual control and engage any of six possible combinations of vibration and oscillation. All data, including the achieved degree of compaction, is shown on the central display and documented in printed form. The operation of such a machine does not require special knowledge and is designed for intuitive perception. The specified system can work together with Bomag Compaction Management (BCM) or BCM Start, which supports GPS positioning, which allows the operator to monitor the results of their work in real time, store data on compaction results over a long period in the system memory, and transmit this data via GSM -connections to the office and transferred to storage media via USB. It is important that with the help of this system you can combine several rollers into one link. Thus, each operator has the opportunity to monitor the performance of all rollers in real time. The system of each skating rink reads data from a server, which is the system of one of the skating rinks, or from a server installed in the office.

The Bomag dealer in the Northwestern Federal District of the Russian Federation is a group (St. Petersburg), which, in addition, offers equipment from a number of other leading global manufacturers. The company's warehouse always has a wide range of spare parts in stock. Particular attention is paid to quality service.

The most important parameters of the asphalt concrete compaction process are the number of roller passes and, as already mentioned, the temperature of the layer. Hamm's HCQ Asphalt-Navigator records these parameters during compaction, links them to the compactor's position information from the GPS receiver and generates a priority map, a true innovation in this field of technology. It shows the operator the areas that require compaction first. Just as modern systems help car drivers avoid traffic jams, HCQ Asphalt-Navigator continuously calculates priority compaction zones based on current data to achieve optimal compaction results throughout the entire site. Priority here is given to surfaces that are already very cool and require several more passes to achieve the desired compaction.

This system eliminates the possibility of the formation of areas with either excessive or insufficient compaction. As a result, Hamm's HCQ Asphalt-Navigator improves compaction quality while reducing costs. And even after the completion of construction work, the HCQ Asphalt-Navigator makes a certain contribution to improving the quality of compaction - the measured data stored in its memory allows the analysis of compaction results over the entire processed area. Based on the data obtained, this system, in addition to the number of passes and the temperature of the asphalt concrete, includes in the analysis data related to the machine, such as the type of roller, its speed, type of compaction (static, with vibration, oscillation, indicating frequency and amplitude), and also takes into account characteristics of asphalt concrete. There is also an o, which is equipped with Atlas Copco (Dynapac) asphalt rollers. Its use allows even an inexperienced operator to avoid the formation of waves and marks on the pavement being laid. For safety reasons, the possibility of emergency braking is provided - when the lever moves sharply, the machine exits the “smooth” mode and stops immediately.

Soil and pneumatic tire rollers

The term “soil compactors” refers to single-drum vibrating machines with tread tires, which are specially designed for layer-by-layer compaction of the subgrade of highways and other engineering structures. Insufficient or improper compaction of foundations can subsequently cause additional costs for the restoration of structures or even lead to their damage. Clay and other cohesive materials require higher compaction loads, which are achieved using heavy-duty padlock roller compaction equipment. Laboratory tests show that frequencies between 25 and 40 Hz (1500 and 2400 vibrations per minute) correspond to the maximum compaction effect on soils. Changing the frequency in this range does not significantly affect the compaction force.

However, changing the amplitude has a significant impact on both the compaction and the depth effect. Large amplitudes are especially important in materials that require significant compaction forces, such as coarse or dry clay soils. Vibratory rollers intended for compacting large volumes of coarse soil, poured in thick layers, must have an amplitude of at least 1.5–2.0 mm. For full operation in Russian conditions, a soil compactor must be equipped with all-wheel drive. It has been tested in practice that inexpensive Chinese cars with a non-drive front drum can slip even on wet sand. Such slippage causes additional stress on the mechanical drive gears, which quickly fail.

Atlas Copco single drum compactors is distinguished by a transverse engine installation, which ensures accessibility of components and ease of service. In addition, the transverse engine arrangement promotes optimal weight distribution and reduces the length of the machine. In turn, the low profile of the hood improves visibility for the operator. An over-compaction alarm system is noteworthy to help prevent damage and extend the life of the roller.

The modern control panel is integrated directly into the armrest of the 180° swivel operator's chair. High performance is ensured by an optimal combination of amplitude, vibration frequency, machine weight and centrifugal force. Depending on the model, Atlas Copco soil compactors (Dynapac) create a linear load from 25 to 65 kg/cm. These parameters, in combination with a high amplitude value of 1.8 to 2.1 mm, make it possible to achieve compaction of the stone embankment on depth up to 2 m, while the stones can be up to 1 m in diameter. It is optionally offered to equip the rollers with a compaction quality analyzer, which allows you to fully control the work process and significantly improve the quality of compaction, and with the help of the CompBase system, select the right machines and draw up a technological map of compaction work.

Note that the most powerful soil compactor in the world is considered to be the Bomag BW332 with a polygonal drum, the effective compaction thickness of which is still unattainable by competitors and reaches 4 m. The roller drum consists of three axially adjacent octagonal elements arranged in a checkerboard pattern. Rings are welded on the side, which facilitate the movement of the roller on a hard surface and prevent it from collapsing when the middle element hits a sharp edge. The peculiarity of the compacting effect when operating a polygonal roller is the constant change in the direction of the acting forces due to its specific shape. The mass of this heavyweight is 33 tons, the width of the compacted strip is 2.4 m. The amplitude is adjusted using the Variocontrol system steplessly from 0 to 3.3 mm at a frequency of 26 Hz. It must be borne in mind that such machines are not created for the sake of records, but due to the fact that the cost of compacting 1 m3 of soil when operating such a roller is lower than that of conventional machines.

The polygonal drum can also be installed on “younger” models of Bomag soil compactors. In total, the company produces about 60 models of self-propelled soil vibratory compactors weighing from 3 to 33 tons. In addition, static compactors for high-performance soil weighing 21 and 35 tons are offered.

The German company Atlas Weycor included road rollers in its line relatively recently, in 2005, but they have already managed to gain the trust of operating organizations. Soil compaction rollers include 5 models weighing from 7,100 to 13,800 kg. During development, much attention was paid to the design of the roller. Instead of the hard-to-find internal bearings used by most manufacturers, the Atlas roller drum is equipped with external bearings. The vibrating unit is installed in a closed, oil-tight pipe that supports the outer drum disks. This is important as it prevents the outer discs from experiencing too much vibration. The internal eccentric shaft (which contains steel balls in dry graphite lubricant) and the entire vibrator unit does not operate in an oil bath, as is usually the case, but rotates above its surface. During its operation, an oil mist is formed, which serves for lubrication. This creates a closed system that requires virtually no maintenance, with abundant lubrication of the bearings. An oil change in the pipe, in a volume of 9 liters, is required every 2000 hours of operation. The drum is attached to the frame only with bolts, so it can be easily removed and disassembled in the field without the use of lifting equipment. The pendulum-type articulation joint (common to all machines) also requires minimal maintenance thanks to Teflon-coated seats. The spacious ROPS cabin with panoramic visibility and a low seating position to reduce the overall height of the machine, with an individually adjustable seat, is equipped with a single joystick with five buttons for maneuvering, changing direction and controlling the vibration unit. The cabin is installed on special bearings that dampen vibration. The special shape of the glass helps reduce noise levels. The rear window is heated. The ECO Speed ​​function ensures that the hydraulic system operates consistently at 100% power at reduced engine speeds (up to 400 rpm below rated speed). Activating the function allows you to maintain the compaction ability of the drum at the same time as reducing fuel consumption.

Standard equipment includes a rear axle with automatic differential lock, a 4-speed hydrostatic drive that automatically provides maximum continuous traction on a variety of ground conditions, and a cab heater. The overmodulation mode of the travel hydraulic motor allows you to overcome slopes of up to 48%. As options, this manufacturer offers an air conditioner, a cam band, and a density meter with a display or printer output. The acceleration sensor is installed on the undamped part of the drum. All information is clearly displayed on a removable liquid crystal display, which can be installed on different machines as needed. The sensor records vibrations of the shell, on the basis of which the value of the current relative compaction is calculated. Thus, the operator is constantly informed about the degree of compaction, amplitude, frequency and speed. At the same time, the device displays the average compaction value, the increase in the degree of compaction after each pass, the compaction graph of the current pass and the location of the machine in the compacted area. In Russia, the authorized distributor of Atlas Weyhausen GmbH for all products and spare parts associated with it is DST-Market LLC (Moscow).

Speaking about static machines, which are too early to write off, first of all you should pay attention to pneumatic tire rollers, which are becoming increasingly popular when working with rigid mixtures such as SuperPave. When compacting, steel rollers rather “push” the material, as opposed to rubber tires, which hold it, as if “kneading” it. Larger particles go lower, and smaller ones end up on the surface. With fine particles on the surface, the asphalt compacts better, reducing the chances of water intrusion during rainy weather. In addition, drops of liquid fractions of bitumen are squeezed onto the surface, which gives the roadway a rich black color that some contractors like so much. For this reason, many people use a pneumatic tire roller as part of a link at a distance of 15–30 m behind the roller roller, which goes immediately behind the paver. The pneumatic tire roller ensures repeated “sealing” of the material and increases its density. This is followed by a roller with steel rollers, which gives the coating a finishing smoothness.

An important property of a pneumatic tire roller is the ability to change its mass over a wide range. For this, a ballasting system is used. Loading and dismantling of modular steel ballast occurs many times faster than ballast with sand and water. Such ballast more accurately distributes the load on the wheels. Unlike steel rollers, rubber tires are inflated with air and are able to precisely conform to the surface being laid (the pressure can be changed). The centralized tire inflation system can maintain equal tire pressure and allows the operator to adjust it on the fly. This is a useful option if the operator knows how to use it effectively. The design of a pneumatic tire roller is such that each wheel on it can vibrate independently. In addition, the tires themselves are also elastic. This property is especially useful for repairing cracks or potholes. With all wheels moving independently, a pneumatic roller can penetrate deep into a pothole and compact more thoroughly, while a steel drum creates a “bridge” over the damaged areas and cannot compact inside. Many contractors are reluctant to use pneumatic rollers because of the potential for material build-up, which not only disrupts the smoothness, but can also damage the integrity of the finish. Sticking can be caused by the tires not being hot enough, the tire pressure being too high, or the roller being too heavy. To avoid sticking, you can use a thermal apron or add a special reagent to the irrigation system. When operating a pneumatic tire roller, it is necessary to check the tire pressure daily - this simple procedure will extend the life of the tires up to 5 years.

Bomag offers three models of pneumatic tire rollers for the European and Russian markets: BW 24 RH, BW 25 RH and BW 27 RH, weighing from 10 to 27 tons. They can be ballasted with available materials: water, sand, metal granules, etc., which provides greater flexibility in choosing the working weight and saves money - there is no need to buy “branded” weights.

Compacting asphalt pavement

First of all, we must remember and understand the main thing: laying asphalt must be started and carried out in dry weather, which is often the sin of our road workers.

Compaction consists of several stages. As a rule, the lowest layer is considered to be the underlying soil, which is pre-leveled and prepared for future construction. Then comes the drainage underlying layer, which fights the effects of natural precipitation and various types of moisture. It serves to remove moisture from under road surfaces. A road base (often made of crushed stone) is laid on the underlying layer. The base serves to distribute the load on the lower layers and ensures frost resistance and drainage of the structure.

Next, the asphalt coating begins. The layers of asphalt concrete pavement are conventionally divided into lower, intermediate and wear layers. As a result, we get a durable coating that is resistant to temperatures and humidity levels.

Asphalt concrete is compacted to the lowest possible porosity of the asphalt layer. An equally important indicator of the quality of the road is its evenness, therefore, at all stages of pouring the road surface, leveling and compaction are carried out.

Chinese version

The share of Chinese products in this segment is significant and amounts to more than 20% of the number of cars imported to Russia. The import of soil rollers in the 12–14 t class is growing at a particularly impressive pace (they already occupy up to 40% of the Russian market for soil compaction machines). These are mainly super-budget rollers with a manual transmission and a non-drive drum. It must be said that this type of machine, only in the 18–20 t class, is the leader in sales in China itself, where it accounts for more than 40% of the total number of rollers sold. With all the variety of brands, there are only three main manufacturers of rollers in China - XCMG, XGMA (due to the absorption of Sanming (Sahm) Heavy Duty Machinery) and YTO Group. Together they account for at least half of the huge Chinese market. In relation to Russia, we can add Shantui, which has significantly strengthened its position in the field of compaction technology over the past two years.

XGMA company (exclusive distributor in Russia - Moscow) actively promotes its products in Russia. From the offered range of XGMA tandem rollers, you can choose a machine to perform any volume of work weighing from 1250 kg to 14 tons. The vibration frequency for machines weighing 7 tons and above has 3 options. The range of soil compactors includes 12 models, including 6 with full hydraulic drive, weighing from 10,000 to 26,000 kg. They are equipped with Dongfeng Cummins turbocharged engines (vehicles weighing 18, 20 and 26 tons are equipped with a Shangchai engine), Bosch Rexroth travel hydraulic pumps and a Sauer Danfoss travel hydraulic motor. The vibrator is driven using a Permco hydraulic pump and hydraulic motor; SKF bearings are used for the vibrator. XGMA pneumatic tire rollers weighing from 20, 26 and 29.5 tons are equipped with a synchronized gearbox. The air pressure in their tires can be adjusted to adapt the machine to different operating conditions. The front axle is equipped with a swing mechanism, ensuring constant contact of the wheels with the compacted surface.

Russian and Belarusian manufacturers

(Rybinsk) - the largest enterprise in Russia that produces a full line of road rollers, which is represented by two new generation series (RV and RC - vibratory and static rollers), and the well-known DU series, offers a pneumatic tire model RC-24SS with a maximum operating weight of 24 t. The roller cabin is equipped with a two-post workstation, which provides a good overview of the working area. Particular attention is paid to operator comfort. The display shows the main parameters of engine operation, temperature and oil pressure in the engine. For quick maintenance, easy access to the power module and pumping station is provided. The roller uses a braking system with dynamic and parking brakes. To ensure safety, engine starting is blocked when the hydraulic drives are turned on.

The 13-ton static roller with an articulated frame RC-13DD is suitable for compacting any type of asphalt concrete and bitumen-mineral mixtures. The advantages of this model include the ability to work on bridges, overpasses and close to residential and industrial facilities, where the use of vibratory rollers is impossible for obvious reasons. The maneuverability of the machine is ensured by hydraulic control and a small turning radius, characteristic of this type of rollers. The width of the compacted strip is 2100 mm, the volume of the plastic tank of the wetting liquid is 800 l. A wide cab with heating, ventilation and dust protection allows the operator to control the roller blade during operation. As an option, it is possible to install a multifunctional display for monitoring and diagnosing the operation of the roller, as well as an indicator of the degree of compaction, air conditioning and a radio.

Another leading Russian enterprise for the production of compaction equipment with 15 years of experience - (Rybinsk) produces a pneumatic tire roller DM 13SP with an adjustable weight from 13 to 16 tons. The roller is equipped with a hydrostatic drive. The roller cabin is also equipped with two workstations; the instrument panel has indicators for temperature, hydraulic oil level and fuel reserve. Features include a pressure irrigation system for pneumatic wheels with interval regulation and a corrosion-resistant coating of tanks.

For ground work, this manufacturer offers an updated model DM-62 weighing 14 tons with a hydrostatic drive, equipped with a Carraro bridge and designed specifically for operation at low temperatures. Optionally, a density indicator can be installed on it, which serves to continuously monitor the relative density of the soil as the machine moves during the compaction process and the vibration frequency of the working body. The plant also produces paving machines weighing 0.5, 1.5 and 3 tons, a full line of tandem rollers from 7 to 13 tons and their combined versions, on which Italian planetary gearboxes are installed. As an option, they are also equipped with a compaction control system. The display shows a continuously updated value, from which you can judge the compaction results during the rolling process, the temperature of the material being compacted and the speed of the roller. All three parameters are taken into account by the operator during operation. The use of the system allows you to increase the efficiency of work and the speed of the compaction process. The static three-roller 13-tonne machine DM-13-SD was created with the participation of representatives of operating organizations and is successfully used, including for compacting thin layers of coatings with high rigidity. The cabins of DM rollers are equipped with heaters as standard.

The Belarusian holding AMKODOR has been producing rollers for soil compaction and asphalt concrete pavements for more than 20 years. The hydrostatic drive from high-torque Poclain hydraulic motors is used for rollers of all standard sizes produced by Amkodor. The machines are equipped with an engine start lock if the drive control lever is not set to the neutral position, they are equipped with three brake systems that operate independently of each other: working, backup and parking. Today the holding produces 8 models of skating rinks. The most popular among buyers are the vibration self-propelled twin-drum 2.7-ton rollers AMKODOR 6223. The 6223E roller, equipped with an LDW 1603/B3 Lombardini 26.5 kW engine, is designed specifically for the European market. The family of standardized asphalt rollers weighing 9–10 tons for road construction is represented by the double-drum AMKODOR 6622V, the combined AMKODOR 6632 with a compacted strip width of 1680 mm, and the pneumatic tire AMKODOR 6641 with a compacted strip width of 1800 mm. Among the new products, we can note the 16-ton soil compactor 6811, which is equipped with an electronic display that displays the speed of movement, the vibration frequency of the vibrator, and the degree of soil compaction. The design feature of AMKODOR single drum rollers is the use of two spaced apart vibration exciters, which promotes uniform distribution of force over the entire working surface of the drum. New generation single drum compactors AMKODOR 6710 and AMKODOR 6620 with modern design and component layout are under development and are preparing for release.

As practice shows, it is not always easy to select the optimal type of road roller for the volume of work received and the specific conditions for their implementation. Taking into account the constantly growing requirements, most contractors approach the selection of this type of equipment with particular care, trying to purchase imported models with many functions that are not always used later. It seems difficult to imagine a skating rink equipped with several electronic systems operating thousands of kilometers from large populated areas in harsh climatic conditions without proper maintenance, and such a situation is not uncommon in our country. Is this approach justified? The high reliability of imported cars is beyond doubt, but the reality is that a large multifunctional display can simply turn off at temperatures below -20 ° C, and the quality of fuel and the qualifications of our personnel are still far from perfect. Considering the current ban on the admission of certain types of foreign-made goods, the list of which includes road rollers, Russian contractors next year will most likely have to pay more attention to domestic and Belarusian equipment, and our manufacturers will have a chance to prove that their products are capable of replacing imported ones analogues.

How to compact asphalt with your own hands

It is better to entrust the asphalting of roads and large areas to professionals who know all the intricacies of working with the material and will be able to create a strong and durable coating. But if you have any construction experience, then you can actually handle simpler tasks yourself.

For example, with your own hands you can:

• Asphalt a small area or parking lot
• Build a walking path
• Arrange the entrance to the house
• Install flooring in garage or storage area
• Repair a hole in the asphalt

To do this, you will need equipment, the asphalt itself (hot or cold), a prepared area and several hours of free time.

In this section we will look at several ways to work with coating:

• Compaction with a roller or vibrating plate
• Sealing with car wheels
• Manual tamping

The table below compares these methods and their effectiveness in different situations:

Explanation of the table:

• “+++” – the compaction method is optimal for the given task
• “+” – you can use this method, but there are better or more profitable alternatives
• “–” – the compaction method is not suitable for this task

For your convenience, we have placed this table below in the form of a picture:

Compacting asphalt with a roller or vibrating plate

This is the most common method used when laying asphalt pavements. It is applicable to both hot and cold ABS.

The only difference is that cold asphalt is a less capricious material. When laying it, you do not need to ensure that the mixture does not cool down.

This instruction is relevant when using:

• Light self-propelled (tandem) roller
• Manual vibratory roller
• Vibrating plates

The order of work will be as follows:

1. Fill the car with fuel (gasoline or diesel) and pour clean water into the irrigation system tank (if equipped) in accordance with the instructions. Start the roller or platen.
2. Start compacting the coating from the area that was laid earlier, and move in the direction of laying at a speed of no more than 3 km/h.
3. Make sure the built-in irrigation system is working properly. If it is not there, the roller drum or slab must be periodically spilled with water from a ladle. For this you will need an assistant.
4. Do not stop on compacted asphalt, otherwise it will cause dents and depressions.
5. When moving to a new lane, you need to place the roller not next to the old one, but slightly overlapping. This is done to ensure that under-compacted seams between the strips do not form in the finished coating.
6. After compacting the longitudinal strips, walk across the coating again - crosswise. It is advisable to go through each lane at least a dozen times.

The compaction process will look a little different if you are working with a round-shaped area (a hole or platform). In this case, you need to move in a spiral and on each circle move 40-50 cm closer to the center.

The quality of the seal can be improved by observing the temperature regime. To do this, you will need to buy or rent a device for non-contact temperature measurement - a pyrometer.

The optimal temperature of the mixture at the time of compaction depends on its composition:

For your convenience, we have placed this table below in the form of a picture:

The maximum temperature is the value at which rolling can begin. If the temperature of the mixture is higher, then under the action of a roller or vibrating plate it will not be compacted, but will be deformed and crushed.

When the asphalt cools down to the minimum temperature, it is useless to continue rolling.

Compacting asphalt with car wheels

This “cheap and cheerful” method is often used in repair work, when holes in the asphalt are filled with cold asphalt.

They do it this way: pour the mixture into the prepared hole and level it. The layer of repair material should protrude about 1 cm above the edges of the pit. Then the car is driven to the pit and the wheels are driven back and forth over it several times.

After compaction, the cold asphalt will stick out slightly above the surrounding surface. This is fine. Over time, it will become more compact under the wheels of cars and give additional shrinkage.

Please note that this method is not suitable for:

• Complete asphalting of areas
• Hot asphalt

Narrow car wheels, and even those located at a fixed distance from each other, will not allow you to evenly roll the coating over its entire area. And the heated mixture will stick strongly to the rubber tires.

Manual compaction of asphalt

Heavy equipment is used to compact asphalt. Its weight amounts to hundreds and thousands of kilograms. It is impossible for a person, even a very strong one, to achieve the same effect manually.

But there are times when you still have to resort to manual tamping.

This method is applicable in small areas:

• In especially hard-to-reach places when compacting with a roller or vibrating plate
• When arranging a blind area
• For pothole repair

Note that the quality of the blind area with this approach will be low. There will be air voids in the asphalt through which water will flow in. To give it the necessary water resistance, the coating will have to be treated with bitumen impregnation or coated with protective paint.

Asphalt can be compacted with a special device (tamper) or with improvised means - for example, a heavy log or timber.

Also, for these purposes, sometimes automated equipment is used - a vibrating rammer (it is also called a “vibrating leg”). But this is not a particularly profitable option. In terms of rental cost, it is no cheaper, if not more expensive, than a vibrating plate. At the same time, using a vibrator over a large area is long and tedious.

Let's summarize everything said above.

When laying asphalt (even manually), it is recommended to use special equipment: rollers and vibrating plates. This is the only way to bring the asphalt concrete mixture to optimal density and strength.

An exception is pothole repair using cold asphalt. Here the material can be compacted using car wheels, or even manually.

If you want to learn more about laying different types of asphalt, check out our related articles:

• Hot asphalt laying technology
• Cold asphalt laying technology
• Technology for laying cut asphalt

And in the final section of the article we will talk about why it is so important to achieve maximum density of the asphalt concrete mixture.