How to roll hot asphalt after paver. What additives may be present in BND? Varieties of asphalt mixtures

The asphalt has deep historical roots; it was already known to the ancient Egyptians and Phoenicians. But, unlike our time, asphalt was intended for completely different purposes than covering ancient roads. If you look at what natural asphalt consists of, then mountain natural asphalt contains up to 75% of bitumen. The name of asphalts itself is due to the Greek word ἄσφαλτος, which can be translated as “mountain resin”.

Slow curing asphalt mixed with low volatility oil. Emulsified asphalt, which is obtained by mixing water with an emulsifier and asphalt cement. This heterogeneous system of spherical globules in the aquatic environment hardens when water evaporates.

Asphalt pavements consist of asphalt, aggregates and voids. A typical mixture is presented in the table. Asphalt pavement Supports applied load, friction and entanglement of particles. Its resistance is a function of surface texture and density of the aggregate. Rough surface texture is desired.

The Egyptians using asphalt were embalming compositions to preserve the mummies of the pharaohs. Avicenna recommended asphalt for the treatment of diseases by analogy with the mummy. Practical Phoenicians and Indians asphalt impregnated their sea ships and canoes. Few people know that until the 20th century the Dead Sea was called the Asphalt Sea, since blocks of this natural material float to the surface.

Dense mixtures are obtained using aggregates with good grain size; the fine aggregate fills the gaps leaving the coarse aggregate structure. A large aggregate is one that is stored in grid No. 8; fine aggregate passes through mesh # 8, and mineral powder passes through mesh #. Mineral powder tends to stabilize asphalt. Bitumen cement binds to aggregate particles and waterproofs the sidewalk. Air spaces allow expansion of asphalt cement or composite compaction, providing a space for asphalt cement to move instead of pushing aggregates.

The history of the use of bituminous compositions

By origin, asphalt compositions or mixtures are divided as follows:

Natural asphalts, which are formed from heavy fractions of oil and their residues after evaporation of lighter constituent components;
Artificial asphalts (the so-called asphalt concrete mixtures) are construction materials made from mixtures of bitumen and other substances.

Unequivocally, asphalt should include bitumen as a binder and mineral aggregates. But if bitumen is included in natural asphalts in an amount up to 75%, then artificial asphalt mixtures contain bitumen in the range of 4-10%. Asphalt mixtures owe their uniqueness to bitumen.

Due to its water-resistant properties and durability, asphalt is used in many construction applications. Asphalts and asphalt products are widely used for roof waterproofing. Asphalt is used as a binder between the layers in the roofs and for impregnating felt, rolls and slabs. Care should be taken not to mix asphalt and resin, i.e. place asphalt layers on resin felt or vice versa if their compatibility is not checked.

Due to its impermeable qualities and durability, asphalt is used in construction to prevent the passage of water, wet vibrations and extensions and serves as a sidewalk. The variety of use of asphalt is amazing. This is a very important material in civil engineering and should be considered at all times.

Interestingly, before the pottery, a Neolithic person used bituminous utensils for cooking. Ancient hunters and fishermen used astringent properties of bitumen when fastening spearheads and for waterproof treatment of their boats. As already mentioned, bitumen in the composition of asphalt was used by ancient healers.

The asphalt waterproofing products developed in our country over the past 10 years have evolved dizzying, creating alliances between asphalt and other materials that optimize the impermeability, flexibility and durability of the product.

On the left side are aggregates moved by belts, and on the right is an unloading silo. It is the only automated plant in the region and capable of producing 200 tons per day. Its computerized management system technological processes was developed and manufactured entirely in our country and has certain technical characteristics that give it an advantage over others in the area.

The first half of the 19th century was marked by the emergence of bitumen-mineral mixtures as a coating of cobblestone bridges in a number of large cities in France, Holland, Switzerland, and a little later in the USA. According to the chronicles of those years, the first asphalt pavement was laid on the sidewalks in Paris in the 30s of the 19th century. Around the same years, the pavement of the Moran bridge across the Rhone in Lyon was paved with asphalt.

All technical equipment is distributed in portable modules, which indicates that the plant is even a mobile plant. The process begins by loading aggregates into silos, they are classified according to the material they contain, each of which is designed for a particular material. Depending on the type of mixture and the required amount of aggregate, they transfer material through belts to the mixing furnace. These belts have an automatic balance that indicates the amount of material that is loaded to distribute only what is needed.

More precisely dated asphalting works in Russia:

1839 - asphalting in St. Petersburg, the length of the pavement was 45.5 linear meters;
Then - part of the Tuchkov bridge with a length of 8.5 meters;
Moscow was slightly behind the northern capital, the pavement was laid in the 70s on Tverskaya Street, but it was already a new, asphalt concrete pavement.

Used in asphalt mixes for pavement bitumen gave elasticity to the roadway, and its ability to spread allowed to evenly distribute the finished mixture, covering the existing bumps in the road. An even layer of road surface immediately attracted attention, sharply reducing the noise effects from passing vehicles. Recall that in the mid-19th century there was no mention of motor vehicles, and cartage wheels were not equipped with inflatable tires.

After loading the aggregates and settling in the mixing furnace, the computer determines, knowing the moisture content of the aggregates, the amount of liquid asphalt required for adhesion of the aggregates to form asphalt or the final product. As we already know, the mixture asphalt concrete pavement must have a temperature in the range from 120º to 160ª, less or more of them will disqualify the asphalt for its use. The computer is responsible for heating the mixture to the desired temperature, then precipitating it into the hopper or dump hopper, from where it is sent to trucks for transportation.

In addition to being used as road material, bitumen is used in a number of other areas of production:

Waterproofing device in buildings, structures, pavements;
With the help of bitumen, waterproofing of the laid pipeline systems is performed;
Bitumen is a part of roofing materials;
Bitumen is needed in the manufacture of filling mastics for batteries;
The cable and paint industry will not do without bitumen.

Varieties of asphalt mixtures

The basis for the classification of the entire set of asphalt concrete is not the basic list of components included in the texture of a particular mixture, but the fractional ratio of the components, that is, the percentage of asphalt plus the values \u200b\u200bof the individual determining characteristics of the included components. As a percentage of the main components, asphalts are divided into three main types:

This discharge hopper has a capacity of 50 tons. The technical diversity of this plant lies in the sand filters that it possesses. They collect dust extracted from the aggregates, which is very harmful for asphalt, as this reduces the slip resistance, forming known black spots on the sidewalk. This collected dust is pushed out of the machine using an evacuation belt, through which the remaining mixture that was in the machine is also removed.

Although they are apparently different substances, the resin is nothing more than liquid asphalt. This is due to the distillation of the resin or oil, and among its properties is high adhesion and waterproofing, because it repels water. Since this is the largest part resulting from the distillation of oil, asphalt boils at a minimum temperature of 600 degrees Celsius. Asphalt, however, can be obtained from other natural sources, such as mineral bitumen. It is used for paving, has several types, and its application varies depending on the type of road that needs to be covered.

Mark 1, the area of \u200b\u200buse of which is limited to the construction of roads and urban landscaping. These materials are not recommended for the role of top coat. road paintings. They are used as a leveling substrate for laying materials of superior density;
Mark 2, which is the notorious "average" asphalt concrete for a wide range of applications, from the construction of new roads to current repair and landscaping;
Mark 3, in which there is no rubble. It is replaced by mineral powders and high quality sand.

It is important! The ratio of the weight fractions of mineral components and bitumen determines the strength of the asphalt concrete canvas. Sand mixtures are suitable only for landscaping the park, while a high bitumen content is necessary to cover the autobahns.
Roads that get heavier freight traffic, for example, need more stable asphalt. One of the methods that has been used, with a positive effect not only on the durability of the road surface, but also on reducing pollution, is the use of mixed scraper tires. This mixture, called asphalt rubber, makes the product more flexible, reducing the appearance of cracks.

A trend that is gaining momentum is the implementation of green asphalt, the use of which is already the goal of several projects in the United States. In these ways, the heat generated will be redirected to the generation of electricity. To increase the calorific value, quartzite is added to the asphalt mixture. In Spain, projects are being developed for the production of special asphalt, which captures the polluting gases emitted by vehicles, reducing atmospheric pollution.

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By natural asphalt is meant rock, a fragile structure, with a low melting point. Formation deposits are often found in places of oil production. In oil-producing areas, water-permeable soils that are saturated with natural asphalt can also be found almost on the surface. Artificial asphalt concrete is a mixture of mineral aggregates with a bitumen binder.

In these experiments, the floor absorbed 100% of rainwater for two months. It is considered a villain precisely because of its ability to waterproof, asphalt is now an ally to avoid one of the most natural disasters in Brazilian cities.

Know our services and the benefits of our product! At this moment of an intensive global process, world leaders put the environmental issue on the agenda as a fundamental asset in all activities developed by man, in particular regarding the exploitation and use of available resources. Since then, Brazil has adopted planning tools to create a sustainable society, harmonize the use of resources with environmental protection, so that human activities cause little environmental damage.

After compaction, the material forms a dense coating highways, sites. In modern construction, asphalt mastics are actively used. When installing roofing or waterproofing, asphalt is used everywhere. Also look at the link http://servisdon.ru/asfaltirovanie/ how to perform asphalting.

Asphalt, which is the subject of this study, certainly refers to the context of environmental impact and, therefore, is a matter of concern for its intensive use, especially on thousands of roads and roads scattered throughout the country. Over time, asphalt has become the raw material for paving roads, streets and airports in the Middle East. It is interesting that at that time it was made with resin extracted from pasty lakes, and not oil, as it is today. The term asphalt originates in ancient Acadian, which means spread.

Asphalt grades

Asphalt concrete is laid in layers, with rolling by heavy special vehicles. Each layer has its own meaning, it has certain requirements. In addition, the brand of material used depends on the purpose of the road, the intensity of its operation. The main differences in the types of asphalt concrete are technical specifications. For example, the underlying layers of the road are produced on large gravel; asphalt with fine sand and stone is used to complete the road carpet.

Subsequently, due to its use as a binder, it became associated with something durable, stable and safe, up to heavy loads. According to its reuse, it is necessary to lay ground tracks. Conceptually, asphalt can be understood as a plastic substance that provides controlled flexibility for mixing with mineral aggregate, which is considered to be strong and stable material, easily adhered, very waterproof and durable. Another concept of asphalt is that it is a thick bitumen of a dark and shiny binder material with a solid structure consisting of complex mixtures of non-volatile hydrocarbons with a high molecular weight, as well as mineral substances, residues of vacuum distillation of crude oil.

On the sidewalks, pedestrian parts of the roads are sand marks. The rubber-bitumen composition is paved with bicycle lanes, stadiums. Crushed stone mastic asphalts steadily endure heavy loads at airfields, city streets and squares with heavy heavy traffic. Polymer-bituminous grades are used in the construction of coatings for bridges and parking lots. The compositions in the finest and coarse aggregate remain the most demanded. The ratio of components reflects the following type classification:

It is not a volatile material, it dissolves in carbon disulfide, it softens at temperatures from 150 to 200 ° C with insulating and adhesive properties. As already noted, from the distant past to the present, asphalt has great social and economic importance in terms of its functions of cementing, gluing, coating and waterproofing, and mainly for laying roads, so that the road and air transport can get around. This study is aimed at assessing the environmental consequences of the production and use of asphalt.

And - half consists of crushed stone.
B - gravel and crushed stone in the composition by 40%.
B - coarse aggregate occupies a share of 30%.
G - has a screening crushing and sand within 30%.
D - natural sand and screening of about 70%.

The state standard GOST 9128-2009 divides asphalt into three grades (I; II; III), depending on the composition and density. The densest is the third class. It consists of sand fillers, bitumen, mineral powder.

To achieve this, we used several authors bibliographies that discuss production, classification, composition, physical properties, and applications in asphalt technology. An analysis of these authors mentioned in this study allowed us to briefly talk about the object under study with a reduction in environmental impact caused by exploration and use of asphalt. However, regardless of the type of asphalt, its function in laying: agglutination and waterproofing. As a binder, it provides a tight connection between the units, capable of withstanding the mechanical effects of vehicle loads.

Mixture composition and production technology

Large and small filler is freed from contamination, divided into fractions, dried. In the manufacturing process, particle size and humidity of the constituent elements is of great importance. When hot bitumen and liquid interact, aggressive foaming of the mixture occurs. Safety rules for working with bitumen prohibit pouring water into a regular container with bitumen. An exception is special devices for road constructionexploiting the antagonistic properties of substances.

As a waterproofing agent, asphalt provides effective compaction against the penetration of rainwater onto the structural layers of the sidewalk. Therefore, we note that this type of asphalt resists water, which does not absorb accumulated water and can contribute to floods. It also characterizes the flexibility of asphalt, since the low chemical reactivity of many agents does not prevent this material from undergoing aging by slow oxidation in contact with air and water, which affects the quality of the road surface.

The bitumen binder is a byproduct of the refining industry. In the formulation of asphalt is not more than 9%. During the entire period of operation, pure bitumen is able to undergo several hundreds of heating and cooling cycles without breaking, then it loses its elastic qualities and crumbles. Therefore, it is necessary to use various additives, plasticizers, stabilizers.

Due to its characteristics, the use of asphalt in road works requires the use of the following bituminous materials, such as asphalt cements, diluted asphalts and asphalt emulsions. In distillation towers, the heaviest part of the oil produces naphtha, kerosene and diesel.

However, asphalt can mainly be considered as a colloidal dispersion of asphaltene particles in an oil medium called maltene, which forms a colloidal dispersion, as shown in the yen micelle model. Simpler fractionation processes separate asphalt fractions into asphaltenes and maltens. Asphaltenes are characterized as hard and brittle solids at room temperature. The percentage of occurrence of asphaltenes is related to the consistency of asphalts. Malteno can still be divided into other fractions.

Sulfur, ash, rubber, rubber can serve as additives. Chemical elements increase the resistance of the coating against frost, aggressive atmospheric exposure. On the asphalt plant apply hot, warm and cold technology. The hot method is a continuous energy-intensive process. Enterprises start production seasonally, with the onset of spring. Cold technique is less expensive, can be applied regardless of the time of year.

Cold production

Foamed bitumen is obtained in special units working with water or steam. As a result of applying this technology, labor costs are reduced, highly efficient mixing of the ingredients takes place directly at the construction site or asphalt plant. Dry filler, repaired, is processed using foam bitumen. travel clothes. The bitumen layer provides good particle adhesion. Foamed bitumens perform well in repair work. For the cold method, moistened aggregates are used.