In recent years, China's road construction has developed rapidly.，With a large number of high-grade roads open to traffic one after another，The maintenance of asphalt pavement is also facing more and more severe challenges.，Especially the urban ring road with large traffic flow.。

Both theory and practice have fully proved that, Whether from the point of view of cost or from the point of view of ensuring the performance of pavement.，Preventive maintenance saves money.、An economical way to extend service life、Convenient、Effective modern road maintenance technology，The benefits greatly exceed the cost of implementing preventive maintenance。

So，In road maintenance work，Effective measures should be taken to carry out preventive maintenance when there is a sign of disease on the pavement.，So that it does not occur or continue to develop and expand.，As a result, the stability at the grass-roots level is affected.。

Project background

Among，The ultra-thin wearing course system is designed for heavy traffic loads.、Maintenance solutions for demanding pavement performance。It is mainly used in the preventive maintenance of high-grade asphalt pavement or cement pavement and the corrective maintenance of minor diseases.，It can also be used as the wearing surface of new road，It is an ultra-long and durable surface layer。

The ultra-thin wear layer will be 15.~25 mm Thick modified hot asphalt mixture is spread on a layer of polymer modified emulsified asphalt tack coat membrane，By the dedicated synchronous paving equipment Vogler Super 1800-3 SJ Carry out construction，The method is characterize in that that spraying of the special modify emulsified asphalt of the bonding layer and the pave of the modified hot asphalt mixture are carried out simultaneously.，Advanced technology of one-step forming after compaction by road roller。

In addition，The ultra-thin wearing layer system has also been greatly improved in adapting to modern maintenance.，Not only synchronous spraying, but also the paving speed is generally 12~18 m/min，5% higher than that of ordinary paver~8 times，Traffic can be opened 30 minutes after the end of rolling.，O as to achieve the purpose of rapid maintenance.，These characteristics are the main needs of high-speed maintenance around the city in Harbin.。

Project overview

The expressway around Harbin has a southeast section.、The west section and the northeast end.，Total length 91.449 km。Take Harbin as the axis.，Xiang Changchun、Mudanjiang、Jiamusi、Suihua、Daqing、The Qitaihe radiates in six directions.“One Ring and Six Shoots”An important part of the expressway system，Harbin Ring expressway is the central hub of highways in Harbin and even in Heilongjiang Province.。

The Southeast Ring was completed and first opened to traffic in October 2001.，During the construction period, a relatively complete pavement project was completed.、Traffic engineering and ancillary facilities along the line，But in the course of its operation，These projects have different degrees of disease.，It has seriously affected the overall image and operation safety of Harbin Ring expressway.，Urgent need for a targeted maintenance。

Considering the speed、Efficient、Environmental protection、Saving and other factors，Heilongjiang Transportation Investment Group Co., Ltd. Ownership expressway Quality Improvement Project Office，The joint design unit, Huashi Design Group Co., Ltd., believes that the ultra-thin wearing layer technology is a reasonable choice for this repair.。

Supervision unit: Zhongzi Highway Engineering Supervision Consulting Co., Ltd.，The construction unit, Heilongjiang Dingjie Road and Bridge Engineering Co., Ltd., has also made a very detailed understanding of the construction characteristics of the ultra-thin wearing course technology and made full technical preparations.，It lays a good foundation for the successful implementation of ultra-thin wear layer.。

Sketch Map of the Location of Harbin Ring Expressway

Construction process

In order to solve the deeper level disease of the upper layer and the middle layer,，Before applying the ultra-thin wear layer，Firstly, the original road surface is milled by a Wirtgen milling machine 8 cm，And then carry out partial plant-mixed hot regeneration on that milled material.，And lay back 6 cm，On this basis，Adopt Vogler Super 1800-3 SJ Spraying paver paving 2 cm SMA-10 Ultra-thin wear layer。

Wittgen W 195 Plus The milling machine is used for milling and planing the original damaged pavement

Fogler Super 1800-3 SJ Carry out double-machine joint paving on that ultra-thin wear layer

Emulsified asphalt spraying and mixture paving shall be carried out simultaneously

Humvee HD 138 The double-drum roller shall roll the mixture closely

After completion of rolling SMA-10 Mixture surface

Equipment advantage

Wittgen New Generation Ultra-thin Paver Super 1800-3 SJ On the premise of technological upgrading，At the same time, it integrates the concept of energy saving and environmental protection.，Its many advantages are more accurate emulsified asphalt spraying.，Better、Greener road construction，Paving of higher quality materials has laid a good foundation.。Mainly in the following aspects.：

01

Equipped with Vogler's proprietary EcoPlus Low emission package，The fuel-saving effect is very obvious.，Remarkable economic and environmental benefits；

02

Unified “-3” Maintenance concept makes maintenance easier，But also remarkably reduce various use costs.；

03

ErgoPlus3. The operation concept and optimized transition mode make the construction more smooth，Construction efficiency is significantly improved；

04

High-precision spray volume controlled by computer，The spraying process is clean and adjustable.，Spraying range is 0.3~1.6 kg/m²，Adaptable to different working conditions；

05

Advanced and precise ironing technology，The flatness of the paving is ensured.，It also lays a good foundation for high-quality construction.。

Benefits are reflected

Compared with the traditional asphalt concrete and the method for paving the overlay,，Ultra-thin wear layer is a model of environmental friendliness，Mainly reflected in the following aspects：

01

Significantly reduce the pollution to the surrounding environment：The traditional scheme is to spread emulsified asphalt tack coat oil first.，And then overlay。Like this，Emulsified asphalt is often picked up by truck tires and paver tracks.。It not only destroys the function of the sticky oil,，It also causes serious secondary pollution to the surrounding roads.；

02

Ignificantly reduce vehicle driving noise：For 2 cm Yes SMA-10，The mixture is of gap gradation.，Larger surface texture，In this way, the pumping effect of the vehicle tires is significantly reduced，Driving noise can usually be significantly reduced，The impact of vehicle noise on residents along the line has been significantly improved.。

03

Significantly shorten the braking distance：As the ultra-thin wearing layer is basically made of stone with single particle size,，Its surface has good angularity.，The roughness of the road surface is greatly increased.。The friction coefficient is high.，Usually 1% of normal asphalt concrete.5x，Therefore, the braking distance is shorter when braking.，The phenomenon of rear-end collision of urban traffic is significantly reduced.，And improve that driving safety.。

04

The road surface water film and the driving water mist are obviously reduced.：It is because the ultra-thin wearing layer has a rough surface texture.，Therefore, its drainage function will play a great role in rainy days.，The area of that wat film on the road surface is obviously reduced，Vehicle tires are not easy to drift.，The concentration of water mist brought up by tire rotation is greatly reduced.，The impact on the vision of the rear vehicle is reduced，So that that drive safety is improved。

05

An ultra-thin wearing course is typically laid to half the thickness of a conventional surface course.，The amount of stone and asphalt can be saved by 50%，And the construction efficiency is remarkably improved.，So from the perspective of energy consumption and emissions,，At least 50.%The above savings，It is a high-performance maintenance scheme with low carbon and environmental protection。

In short，Super 1800-3 SJ Synchronous spray-type paver，It is also a multi-functional device.，Can be use as a spreader of an ultra-thin wear layer，But also can be use as a common paver.。Among them, the ultra-thin wear layer is a preventive and corrective maintenance measure with extraordinary durability.，Can achieve a variety of desired economic、Social benefit。

These include the benefits of slowing the deterioration of pavement conditions and reducing routine maintenance；Benefits of Extended Pavement Life；Improved driving conditions、Benefits of reducing traffic accidents；Increase the coefficient of sliding resistance，Benefits of reducing road noise, etc.。

The successful application of the ultra-thin wearing layer in the quality improvement project of Harbin Ring Expressway，It will certainly make more contributions to the regional economic development of Harbin.，It will also provide more reference for the double carbon target of transportation direction in Heilongjiang Province.。