Recently，Cold-in-place recycling technology of Wirtgen foamed asphalt based on synchronous paving in Laixi City, Shandong Province SSuccessful Application in Large and Medium Repair Project of 502 Nanwu Line，This is the first time that the full-depth foamed asphalt cold recycling technology has been applied to the restoration of Shandong provincial trunk highway.，At the same time, it will also provide a good reference for the future national and provincial trunk highway maintenance projects to open up new structural forms and maintenance programs.。
Project summary
S502 Nanwu Line is between Laixi City and Zhaoyuan in the northeast of Shandong Province.、A north-south trunk highway between Longkou，It is the main road for mineral transportation.，It is also an important channel for Lacy to connect with the surrounding areas.。The Laixi section of Nanwu Line is a second-class highway.，Two lanes in both directions，With hard shoulders，Pavement width 12 m。After years of traffic load and UV aging，The pavement condition index decreased to a certain extent.。
The main pavement disease before maintenance is fatigue crack.、Rut、Net crack, etc，Poor flatness，It seriously affects the comfort and safety of driving.，A comprehensive and complete restoration is urgently needed.。In order to better respond to the national call for low-carbon roads and circular economy.，And for new materials.、New Technology、New technology、Popularization and application of new equipment，After research, it is decided to apply the cold in-place recycling technology of low-carbon high-performance foamed asphalt based on synchronous paving to repair some sections of the road.。
Regeneration process
Along with the powder spreader、Asphalt tanker with Wittgen W 380 CR Cold in-place Recycling Machine、Regeneration unit composed of Vogler Paver for one-stop operation，The brand-new pavement base is presented in front of us.，Let the people present witness the power of technology and innovation.。
Full-depth foam asphalt cold recycling technology adopts special foam asphalt on-site cold recycling equipment.，On-site milling of asphalt pavement，Adding a certain proportion of foamed asphalt、Cement、Water，Mixing at normal temperature on site、Spreading、Rolling and other processes，Technology of Regenerating Pavement in One Time。The total length of this test section is 2 km，Quantities 2.40 thousand m²。
According to the regenerative maintenance plan，Pre-removed by the Wirtgen Milling Machine7 cm Damaged asphalt surface course。The milled old asphalt material will also be recycled.，Reuse by way of plant-mix hot regeneration，It is used as the surface layer after the completion of the cold in-place recycling layer of foamed asphalt.。
Milling off 7 cm After damaged asphalt pavement，By W 380 CR Proceed 22 cm Thickness recycling construction，Milled partially damaged bituminous material and old cement stabilized material，Accurately add the corresponding proportion of water and foamed asphalt，And be mixed simultaneously with the previously spread cement，Nerating new foamed asphalt cold recycling mixture。The regenerated material consists ofW 380 CRInto the next Vogler Paver hopper，The mixture is mixed again by the Paver auger and conveyed to the paver screed to complete the back paving.，Finally, it is compacted by several Hummer rollers.，Forming a large-thickness foamed asphalt cold regeneration layer。The whole construction process only occupies a single lane.，Very smooth and efficient。
Technicians use sand filling method to test the compaction degree of the road surface after compaction on site.，The test results meet the construction requirements.，Other indicators also meet the design requirements.。After the rolling is completed, light traffic is opened.，Minimize the impact of construction on traffic。Coring test shall be carried out every other day after the test section is opened to traffic.，A complete and compact core sample has been taken out.，The regeneration effect is very good。
The environmental protection and economic benefits are remarkable
Compared with the traditional technology，Full-depth recycling technology realizes the in-situ recycling of old pavement base.，And that run cost of materials is save.，And that construction energy consumption is low、The pollution is small。Full-depth foamed asphalt cold recycling can not only retain the strength of the base,，Increases the fatigue resistance of the material，Improves the characteristic that the traditional semi-rigid base is easy to crack；Compared with the traditional maintenance scheme，The construction period is saved by about 50%，Cost saving approx. 20%，Reduce heating energy consumption by 60 percent%Above，Reducing CO2 emissions 80%Above，Highlighting new technologies、Rich economic benefits and high-quality environmental protection benefits brought by new technology。
In recent years，Highway Center of Qingdao Transportation Bureau insists on“Quality、Innovation、Green、Environmental protection”The idea of，Introduce new technology in many ways，Actively adopt new technology，Continuously optimize the design scheme，Strict control of project quality and safety，It has achieved a double harvest in engineering construction and scientific and technological application.。The introduction of full-depth foam asphalt cold recycling technology not only greatly improves the construction efficiency，It also conforms to the concept of the national dual-carbon strategy.，It has contributed to the sustainable development of green and low carbon.，Once again, it shows the innovative ability of Qingdao traffic highway.。
