外文翻译----浅析沥青混凝土路面的施工质量控制

附录

Asphalt Concrete Pavement Construction Quality Control

Li Gang, low Income

Abstract

This paper is the combination of highway pavement maintenance based on the work, by analyzing the formation mechanism of asphalt concrete pavement, asphalt pavement during the construction period on how the construction quality control issues to present their views and experiences, to prevent the development of Pavement Distress on the current asphalt concrete pavement by the phenomenon of high incidence of disease has a certain reference.

Keywords: Highway; asphalt concrete pavement; Construction Quality Control

1 A road surface disease and major hazards

1.1 surface pits

Highway pavement surface pits is the earliest of the disease, especially in the rainy season. Likely to cause road bumps, the high speed of the car and the large tonnage of the vehicles, the larger the depth of deep trenches and even endanger traffic safety. In addition there are destructive pit road development, the so-called "do not fill a hole, big hole to suffer."

1.2 Pavement Rutting and own package

Pavement rutting season usually occurs in high temperature, especially after the hot season will still be within one month of development.

Owned by packages in two situations: First, and pavement rutting the same time and place; Second, in the individual sections of a small area (area ≤ 6m2) occurred. Pavement rut and own package is mainly caused by car bumps; rain will cause water in the street, reducing pavement skid resistance, thereby endangering traffic safety.

1.3 Pavement Cracks

Pavement cracks occurred mainly in winter, with transverse cracking.

Performance in the rain season, the most obvious, or even jack pulp phenomenon. Crack key hazards are as follows: First, the formation of surface pits is easy; Second, surface water would seep into the surface layer of the internal and road base, pavement damage.

1.4 pavement cracks and loose

Pavement cracks and loose most evident in the winter. In the rainy season, especially in cold weather, rain season, the road tends to form cracks and loose a large area (area ≥ 1m2) of trenches and pump slurry, together with infiltration of surface water within the surface layer and the road base, threatening the entire pavement structure .

1.5 Pavement Bleeding

Bleeding caused by road pavement skid resistance is mainly down, for a motor vehicle traveling on the highway, down the road skid resistance led directly to the brake and steering performance degradation, endangering traffic safety.

2 Formation Mechanism of Pavement Distress

2.1 surface pits

The formation of surface pits is because of water damage. In a lot of fast traffic load, tire position and the hydrodynamic pressure generated by vacuum suction from the surface will result in gravel asphalt concrete flaking out, or cause weathered stone, gravel and so crushing strength difference. Through the cycles, the formation of pits.

A lot of impurities in the aggregate, gravel aggregate pro-poor quality and poor sections of this oil is most obvious. Also, if road loose, cracked, old and new pavement cracks and joints, poor road handling, pit has also greatly increased the likelihood.

2.2 Pavement Rutting and own package

Pavement rutting and the formation of complicated ownership package, mainly the following aspects: First, the destructive effects of overloaded vehicles; second, high temperature stability of asphalt concrete road surface worse.

The former is caused by a key factor in pavement rutting. In accordance with the Ministry of Transportation design and technical specifications related to testing standards, the pavement load for the rear axle load 100kN, tire pressure is 0.75MPa. But this year, nationwide auto gauge control work, before driving on the highway most of the large trucks for more than 30% overrun, and some even as high as 180KN, tire pressure up to 1.1MPa.

High temperature stability of asphalt concrete road surface is poor, particularly in like 2003 and this continued under the influence of high temperature, surface temperature is often above 70 ℃, then the internal, such as road surface temperatures in the surface layer of a higher and longer duration . The main role of the middle layer is a permanent deformation and rutting resistance, according to Chinese and U.S. scientists study shows that: Rut is the main part of the road surface 5cm-10cm.

For semi-rigid pavement, if the primary does not damaged, then the rutting in asphalt concrete pavement is to generate the. The road surface temperature stability are the main reasons are the following aspects: high oil content of asphalt concrete, asphalt sensitive to temperature, too few or broken coarse aggregate caused by lack of interlocking forces face down, Fine Aggregate excessive amount of river sand, asphalt concrete compaction can not meet the requirements and so on.

The reasons for the formation of road owned package addition to the above aspects, there are two reasons: First, the heterogeneity of road construction; second, poor road surface roughness. Both rough driving in the car, because cars under impact, likely to cause pavement depression. And this depression is the "Matthew Effect", depression after high-speed automobile road will have greater impact, while the larger the impact will be greater depression.

2.3 Pavement Cracks

Pavement cracks are mainly two: one is the shrinkage of asphalt concrete pavement cracks; a Pavement cracking is a result of reflection cracks. As the ductility of asphalt concrete is superior to semi-rigid base, especially in cement stabilized base. As long as the extension of their degree of asphalt and asphalt concrete to meet the

design requirements of the oil content, the temperature cracks generally occur less and less effect. I come into contact with the highway pavement cracks, especially in transverse fractures, mainly reflective cracking.

As the basis for asphalt concrete pavement, cement stabilized base with flexural strength requirements. However, the specific construction and quality control process also must be strict control of its cement consumption, meeting design demands strength of the premise, as far as possible reduce the amount of cement, thereby reducing the occurrence of reflective cracks and reduce the crack width.

2.4 The pavement cracks and loose

Pavement cracking is mainly caused due to structural damage. If not meet the design requirements of grassroots flexural strength; or under the limit vehicles, primary loads exceeding the design load, the grassroots will be destroyed.

Loose road surface itself is usually the reason, impurities such as aggregates, oil pro-poor aggregates, asphalt concrete oil-less so.

2.5 Pavement Bleeding

Asphalt concrete pavement weeping mainly high in oil content, aggregate interlocking due to insufficient strength of asphalt and fine aggregate on the pan due.

3 of road construction quality control

Quality control is a key construction process work. FIDIC provisions in accordance with the relevant technical specifications and the Ministry of Communications is a comprehensive and systematic work. In this article, the writer for the disease on some major aspects of the road a little about their own experiences.

3.1 Selection and storage of raw materials

3.1.1 Aggregate

Pavement construction aggregate consumption of a large, 12000t/km above. So choose a suitable aggregate in control of the production costs and improve the quality of construction is important. Special attention should be on aggregate following matters:

3.1.1.1 In the same layer, the aggregate materials and ingredients should be as consistent as possible, so as to ensure the uniformity of the structure layer.

3.1.1.2 Aggregate weathering conditions and sediment content should be strictly controlled, particularly in the surface layer of material, "a mud hole is a" clean aggregate level, directly affect the conservation effort.

3.1.1.3 Aggregate surface directly affect the pH of aggregate and asphalt adhesion. Therefore, in the choice of surface materials and asphalt together must take into consideration, the two must meet each other in order to achieve good results.

3.1.1.4 Primary general construction with continuous mixing, which requires the storage of primary aggregates and stacked to be carried out strictly in accordance with specifications, to prevent segregation. Can guarantee the uniformity of base construction.

3.1.1.5 Aggregate stack space necessary to do the site hardening and different specifications of the work piling up aggregate segregation.

3.1.2 Binder binder means: Cement Stabilized surface layer of cement and asphalt. Both are key materials in road construction.

3.1.2.1 Cement requirements: low heat of hydration to reduce the primary crack; retarded to meet the construction schedule; stability is to ensure that grass-roots strength.

3.1.2.2 more stringent requirements on the asphalt, and some indicators of mutual restraint, many times in the test and design to achieve the best results. Specific such as: high temperature stability requirements in order to ensure consistency of high and low temperature sensitivity, in order to ensure consistency requirement of low temperature cracking resistance and low temperature sensitivity. Different regions and different aggregates will make different demands on the asphalt, it should be according to local conditions, choose a good pitch.

3.2 Mix Design

Pavement mix design is the key to many factors must be considered. This article will mix the surface layer should be based on, the following features layers to design.

3.2.1 Mix Design grassroots cement dosage should be strictly controlled

Designed to meet the minimum strength of the premise, to minimize the amount of cement.

3.2.2 good grading

Grass-roots base material mix design and construction machinery should be the case do aggregate grading design, so that the final produced good grass-roots level mixture distribution.

3.2.3 The following layer

Mainly subjected to various stresses, including compressive stress and shear stress. Should be a higher consistency of asphalt and aggregate gradation good.

3.2.4 in the surface layer

Primary role is the resistance to permanent deformation or rutting, also asked a good anti-seepage performance. Therefore, when the mix design should pay attention to the issue of oil content, oil content can decrease the surface layer of anti-rutting performance, too low will affect the seepage features. Accompanied in the aggregate should be increased very aggregate amount of more than 10mm to improve the asphalt concrete interlocking force, thereby enhancing the anti-rutting performance. To reduce porosity, improve seepage performance, consider the following to improve 5mm, 2.36mm or even less amount of fine aggregate.

3.2.5 Top Surface

Main function is to provide a sliding car, flat surface. While the top layer and atmospheric exposure, most affected by temperature, low temperature cracking resistance of its most demanding. Therefore, consistency should be little above the layer of asphalt. At the same time should be strictly controlled asphalt content and fine aggregate, prevent the opening of the road weeping. Above the floor to pick a good set of hydrophobic material, to enhance the hydrophobicity of aggregates, experienced construction unit will use cement as a filler. However, a large amount of cement will often bring a decline in low-temperature cracking resistance, the design should be strictly controlled.

3.3 Construction

3.3.1 Construction of Test Road Test section of the role is very important to obtain the following test results section.

3.3.1.1 Verify whether the mix design and construction requirements to meet.

3.3.1.2 Compaction requirements to meet the compaction times and with this number corresponds to the compaction coefficient.

3.3.1.3 Operation in mechanical with the number and type, determine the maximum efficiency and cost-effective in controlling the mechanical combination.

3.3.2 Deflection

Before construction of the embankment and sub-base for deflection detection, can not meet the requirements of section deflection must be processed.

3.3.3 Mixing strict calibration measurement parameters

Mixing the materials to ensure uniformity.

3.3.4 ensure that the machinery of normal use

When the hybrid materials and the materials and paving, rolling and curing time. Base construction paving and rolling if not promptly, once after a final setting of cement is still rolling, it will be the final setting of cement or grass-roots can not crack.

3.3.5 health

Cement Base in a timely manner after completion of construction health, which can effectively reduce shrinkage cracks.

3.3.6 Bond strength

Layer and through the layer under the seal and the surface layer of the primary bond between the ability to have great impact bonding solid surface and base, levels of driving thrust of the primary can be effectively delivered.

3.3.7 Surface treatment

Surface before construction of the primary crack has been found to process, to shop glass fiber grid method for processing.

3.3.8 Regular inspection

Although batch mixing with asphalt concrete, asphalt, filler and aggregates of different sizes are individually weighed. But they still had regular tests to ensure the accuracy of the amount of various materials.

3.3.9 Paving temperature and rolling temperature control

Paving mixture of good temperature control, to avoid mixture of Segregation in the paving process. Mixture in rolling, the temperature is too high and too low are difficult to meet the design degree of compaction and air voids.

3.3.10 Pavement smoothness control should be started from the grassroots

This will not only ensure the best results to the top layer of the flatness, but also avoid the flatness Ershi to meet a larger surface thickness occurring mutations.

4Conclusion

Asphalt Pavement are many reasons for the formation, but the construction quality is the main reason for the formation of disease. Construction and maintenance of our often disjointed, construction teams generally responsible for the quality of construction and one year defects liability period of conservation. The disease appears in a lot of asphalt pavement quality defects liability period, these diseases are generally more difficult the problem back to the construction team.

In the road construction process, some construction companies, and even supervision units, construction of the road have some misunderstanding, mainly as follows:

(1) re-surface layer, and that it in fact semi-rigid pavement of the main bearing structure is the grassroots, grass roots in the fundamental role played pavement structure;

(2) above the layer of heavy, light, the following layer, the road surface structure, the upper, middle layer of each of the following division of their duties, not favoritism. Only three have full play to their effectiveness, to achieve the best results;

(3) re-combination of materials, lightweight aggregate, aggregate in the pavement structure is the main force in the asphalt concrete pavement, the aggregate interlocking force on the asphalt concrete stress plays a very important role.

Aggregate as to material, its selection, processing and storage have to be strict checks to ensure the quality of roads.

References

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[2] Ruckel PJ, Acott SM, Bowering RH. Preparation of design mixes and treatment of test specimens. Transport Res 1983;911:88-95

[3] Nataatmadja A. some characteristics of foamed bitumen mixes. Transport Res 2001;1767:120-5