THE IMPORTANCE OF ROAD COVERINGS IN ROAD CONSTRUCTION, ITS DESIGN AND TYPES
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This article provides detailed information about pavements used in the Road Construction system, their importance, design and types of pavements, and an overview of the concept of pavement, the general set of layers, and the durable pavement layer reflects.
Key words: Road construction, pavement, design, layer, automobile, structure, rule, pavement, safe, stone, soil, quality, infrastructure, movement, asphalt-concrete
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Surkhandarya region IIB JXX YHXB YPXB 1
Mobilization group YPX inspector in charge
Abduraxmonov Jaloliddin Nuriddin o’g’li
Abstract: This article provides detailed information about pavements used in the Road Construction system, their importance, design and types of pavements, and an overview of the concept of pavement, the general set of layers, and the durable pavement layer reflects.
Key words: Road construction, pavement, design, layer, automobile, structure, rule, pavement, safe, stone, soil, quality, infrastructure, movement, asphalt-concrete.
It is no exaggeration to say that beautiful and tall skyscrapers, roads and bridges are being built in all regions of our country in recent years, and this is adding to the beauty of our country. This definitely shows that our country is developing. Here we can say that today the road construction system is developing rapidly. Road construction, its design, road surfaces and types are also developing rapidly. The introduction of new solutions in the industry, mainly the appearance of modern machines, tools and equipment for the preparation and laying of various layers, definitely affects the technical support. New research is being conducted on the materials used to cover city roads. Today, in the works of construction, repair and reconstruction of highways, the "Directorate of construction and reconstruction of public highways" within the Committee of Highways under the Ministry of Transport is the customer. These works are performed by other enterprises within the committee on the basis of a contract. This directorate is also responsible for accepting the completed works. The quality of the materials used and the work performed is carried out by the inspection of the quality control of road construction works under the Ministry of Transport. "Customer", "Contractor" and "Quality inspection" for road works are carried out by enterprises under the jurisdiction of one ministry.
Applying international experiences to improve the quality of construction works - not only
allows to create a quality management system, which regulates the solution of all issues necessary for the performance of high-quality construction works, but also to use it in practice. To do this, develop the market for consulting services
need Public-private partnership in the field of highway quality management
It is also important in organizing work based on this. Therefore, on the basis of the decree of the President of the Republic of Uzbekistan No. PF-5890 dated December 9, 2019, it was determined that consulting services (technical control) for road construction works will be performed by independent organizations in accordance with international practice, including FIDIC rules, based on the terms of outsourcing. . ShNQ 3.03.06-08 is the main normative document for the construction of highways in our country. This standard specifies requirements for quality control of road works and the construction process. At the same time, ShNQ 3.03.06-08 is complemented by requirements of other GOST, U`zDST, MShN (MQN, IQN) documents. Based on this, it is necessary to develop national model contract conditions for local projects, taking into account the requirements and technical conditions of ShNQ, GOST, UzDST, MShN (MQN, IQN) and legal documents on the territory of our country. The experience of developing and implementing such national model contract conditions is widespread in European countries. An example of this is the following contracts developed in Germany and England:
- JCT – "Joint Contract Tribunal Limited" (England);
- ICE - "Conditions of contract" (England);
- NEC/ECC – New engineering contract/ Engineering and construction
contract (England).
In short, regulated contract terms in the construction industry
prevents various problematic situations that arise, a true assessment of the situation
helps in giving, clearly defines the rights and obligations of the parties and increases the quality and speed of work. This, in turn, is the development of this industry
provides and significantly helps in the growth of the country's development.
One of the disadvantages of this FIDIC system is that it presupposes the availability of qualified professionals to execute the contract. Coatings are also based on cement fillers, gravel sand and binders. Of course, new modifying components with additions are introduced more and more, but they have an important feature to increase operational characteristics and do not fundamentally change the characteristics of standard structures. Asphalt-concrete and cement-concrete are often the basis of roads. In both cases, the characteristics of the binder, crushed stone fractions, sand and other fillers may differ. In fact, the finished structure of such coatings can be considered a complete pavement. The definition refers to a general set of certain coating layers, but each layer works as a separate technological component, with special requirements for its device. In order to ensure the reliability of the coating, it is necessary to ensure conditions in which the stress caused by movement in the structural elements does not have a destructive effect.structure. This can be achieved by rational calculation of the characteristics of the structure, which is carried out by technologists before the start of road works. The appearance of simple road surfaces on which traffic is carried out hides a complex structure consisting of several layers
Each layer has its own device rules, features and technological purpose. Provided that all layers are of high quality, a safe and durable coating can be obtained. It will be a corridor that will form the main infrastructure for the movement of cars. Typically, designs are developed as universal pavements for both urban and rural roads. It doesn't matter if it's a highway or a street.
In developing the project, the level of traffic intensity, characteristics of the materials used, loads, hydrological and soil conditions, as well as other factors affecting the performance of road surfaces and foundations are taken into account. On unpaved roads, small-scale pavement structures are provided. In particular, the design of this type of pavement includes the calculation of the allowable deflection of the pavement under unfavorable conditions in terms of external conditions, seasons of the year. Reversible deflection is calculated from one basic property - modulus of elasticity. The resistance of the upper layers of the soil, where the foundation will be laid in the future, is also taken into account. For this parameter, technologists enter the magnitude of the shear stress. If deviations from the equilibrium norm in one of the layers can lead to residual deformation processes, then the design of the coating may include changing the composition by adding new plasticizers and technical components that increase the stiffness of the foundation . All standard designs of coatings are divided into two categories - hard and non-hard. At the same time, each technological model of the coating device
implies the use of specific indicators of moisture, thickness, size of the sand fraction, crushed stone and, in general, the properties of the cement-sand base. Thus, the modulus of elasticity of the soil base, depending on the design used, can be on average 300-500 kgf / cm2. As an exception, it is possible to cite structures that are not related to the construction of a sand layer for drainage. In this case, the design of non-rigid pavements, intended for laying in sandy and sandy soil conditions, is carried out. The modulus of elasticity of such a base can reach 1200 kgf/cm2. Designs also differ in the number of technological layers. An important component of urban infrastructure improvement is the sidewalk. Its surface also belongs to the types of pavements, but, of course, it has other technical and operational characteristics designed for pedestrian traffic. Pavement constructions in different regions do not differ much from each other, because the climatic conditions have less influence on their coatings. Nevertheless, the design takes into account the category of the street, its purpose, the intensity of pedestrian traffic, the characteristics of the soil base, as well as the ratio of the sidewalk to the carriageway. In the standard form, the design of the pavement can be carried out under the conditions of reinforced soil with the help of asphalt and cement mortar. In some cases, ceramic and asphalt-concrete slabs, as well as weak ones based on natural stone, are used. In this case, laying can be done in several layers, as in traditional roads. Perhaps this is the most important part of the overall design, because it is responsible for the function of connecting the top cover to the ground, as well as for the distribution of loads. In practice, the support provides a reduction in stress from the action of the wheels, transfers the power potential to the ground. Thus, due to the ground cover, the foundation creates a specific damping effect.
But the pavement does not always have the appropriate properties of the foundation in terms of protection from external influences. For example, the bottom layer may have optimal working quality, but it gradually erodes under the influence of water. On the contrary, it can resist climatic effects, but at the same time it performs poorly in load distribution. Builders also separate functional layers from the underlying structure to optimize various features. Thus, the carrier part and auxiliary layers are considered separately. In such a structure, the main coating is responsible for mechanical resistance, and additional coatings resist the same precipitation. The outer surface also performs a number of important functions, the main of which is the direct reception of loads from vehicles. A direct connection also occurs in connection with climatic precipitation, so the protective qualities of the upper part can be called universal. The multi-functionality of the outer coating is achieved due to several layers, as in the case of the sole. Thus, geogrid and geotextile, as well as special interlayers, which may contain modified binding components, are used to increase the resistance to cracks in the pavement. The surface of the pavement has a special treatment, which also protects the coating from moisture and snow. And in addition to protective qualities, it is also used to strengthen the adhesive properties of the surface. For example, special treatment is also used to increase roughness and improve grip on the road with wheels. Depending on the operating conditions, various negative factors can affect the road surface. Not every typical design can meet the increased loads in terms of thermal, hydrological and mechanical effects. For example, non-solid pavements are highly drainable and do not need additional layers of sand, but their strength properties may need to be strengthened. For this, layers are created between the bearing part and the upper layers, and polymer film layers between the technological base and the primer.
CONCLUSION
In conclusion, it can be said that the climate is also very important in the road construction system. That is, Cold is the most harmful climate effect. Protection when working in negative temperature conditions includes the use of granular materials, including sand, sand and gravel mixtures, and crushed stones. A type of insulation can also be a soil base, on which a coating is formed with layers of substrate. However, to prevent freezing, the floor covering is not enough, i.e. it is supplemented with reinforced binders, as well as hydrophobic barriers. This type of technological layer is used in areas with bottom layers made of undrained soil. Mandatory inclusion of such layers is considered in areas with high rainfall. The main function of the drainage layer is to provide drainage. In addition, for urban roads with a higher drainage layer compared to the depth of freezing, standard pavement structures should be made only of durable and frost-resistant materials. The most dangerous event that leads to improper use of pavement technology is breakdowns. In such cases, there is a risk of complete destruction of the network along the entire thickness with the appearance of sharp distortions of the structural profile. Peeling and chipping processes are less dangerous, indicating surface damage due to the breakdown of adhesives and the loss of individual particles of mineral fillers. Common mistakes made with conventional pavement design can also lead to slippage and potholes. The formation of an open abyss also pushes the soil to the surface, which makes the cover unusable
REFERENCES
Amirov T.J. Yo‘l qurilish ishlari sifatini nazorat qilishda FIDIC metodikasini qo‘llash. «Orol bo‘yi mintaqasida me’morchilik va shahar qurilishi barqaror rivojlanishi masalalari» mavzusida xalqaro ilmiy va ilmiy-texnik anjuman materiallari to‘plami. QDU. Nukus, 22-23 aprel 2021 yil. 396-401 betlar.
Мирахмедов М.М, Досметов С.К, Садриддинов Б.Б. Организация строительства в рыночных условиях: порядок разработки, проведения экспертиза и утверждения документации инвестиционных проектов, заключение и исполнение инвестиционных договоров по международным правилам. Электронное издание. Ташкент 2013
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