The project is located atG Sanguan-Loutai Section of National Highway 242, Zhushan County, Hubei Province，Route length 14.88 km，The technical grade of the highway is Grade II.，Two lanes in both directions。

Project overview

Since the construction of Baoyi Section of Shiwu Expressway started in May 2018, a large number of heavy construction vehicles have been transporting construction materials and abandoned dregs.，Causing serious potholes.、Subsidence and other diseases，The road surface is seriously damaged。

In order to completely repair the pavement damage,，At the same time, protect the beautiful local natural environment.，And that construction cost is save，After the demonstration of the scheme，Finally, Wittgen was adopted. W 380 CR Design Scheme of High-performance Foamed Asphalt Cold In-place Recycling Technology for Rehabilitation。That is to say, first of all, after the disposal of the old road base diseases,，Cold in-situ regeneration of the original asphalt surface with foamed asphalt，Normal hot asphalt chip seal shall then be applied，Final overlay 4 cm SBS Modification AC-13C，Road elevation 4 cm，4 is used on both sides of the road cm Thick C25 fine aggregate concrete。

Construction equipment

Hubei Yida Highway Engineering Co., Ltd. introduced Wittgen in 2022. W 380 CR Cold in-place recycling equipment and technology，It also undertakes the cold recycling construction task of this project.。

The main construction equipment of this project includes Wirtgen in-situ cold recycling machine. W 380 CR ，One gravel distribution truck，One cement distributor truck，Two waterwheels，One asphalt insulation tanker，Vogler Paver Super 1880 L One，Humvee HD One 138 double-drum road roller，HC 228 D One single steel wheel，Rubber-tired roller HP 280 one set，A loader。

Construction steps

Because the construction section is the main traffic artery in the area.，Heavy traffic，Completely closed construction is not allowed，Therefore, traffic control was carried out on half of the road before construction.，Setting out according to road chainage and width。Sample the asphalt surface of the construction section before the construction of the project.，The design of cold recycled mixture of foamed asphalt is completed.。

During the regeneration of foamed asphalt，After the gravel distributor is calibrated, pre-spray 15 in the regeneration lane.%Graded crushed stone，Then the cement distributor truck shall be installed according to 1..8%Spreading shall be carried out according to the cement content；The mixing water consumption of the cold recycling machine is 2.8%，Construction speed of in-situ recycling machine is 4 m/min，The content of foamed asphalt is 2.5%，Regeneration thickness is 8 cm，The coefficient of loose paving is 1 during paving..4。

After paving, it shall be rolled by Hummer roller combination.。First, use the Hummer single-drum roller for static compaction for the initial compaction.，Then weak vibration twice.；Hummer double-drum roller shall be used for re-compaction for two times of weak vibration.；Hummer rubber-tired roller shall be used for final compaction for 5 times.、Finally, double steel wheels are used for finishing.。

   Graded macadam pre-sprayed by macadam distributor truck

   Cement spreading truck for spreading cement

   W 380 CR Carry out on-site recycling operation

   Vogler Paver Super 1880 LCarry out back paving on that foam asphalt cold recycling mixture

   Hamm HD 138 double-drum roller reloading

   In-situ regeneration layer of foamed asphalt after rolling and forming

   Cold in-place recycling of foamed asphalt 7 d Age core sample

Test data

According to《Technical specification for recycling of highway asphalt pavement》（JTG/T5521-2019）Requirements of，Sampling of on-site foamed asphalt cold recycling mixture，Conduct strength and water stability test。The test result data shows that，The splitting strength and water stability of the mixture on site fully meet the design requirements.，It shows that the quality of on-site mixture is good.。

Engineering application summary

· For areas with scarce resources，Green construction technology of cold in-place recycling based on synchronous pavingMay be 100%Utilize local materials，Reduced mining and use of road-building materials，And minimize the cost of the project.，Beneficial to the development of local road industry。

· Maintenance and repair of mountain roads，High degree of mechanization of cold in-place recycling construction based on synchronous paving，Flexible construction，Small impact on traffic。

· Every dayFinish 6000~8000 ㎡ Workload，High efficiency and energy saving，The construction period can be greatly shortened.。

At present，The cold in-place recycling technology of foamed asphalt based on synchronous paving has been used in Shiyan, Hubei Province.、Xiaogan、It has been widely used in Qianjiang and other places.。

According to the detection data in the later stage of application，This technology mitigates reflective cracking.、Improve driving safety and comfort、It has a good advantage in improving traffic conditions.。Its social benefits、The economic benefits and environmental protection benefits have also been well reflected.，This will provide a valuable reference for the maintenance of other road sections in Hubei Province.。