沥青路面就地冷再生基层（底基层）施工工艺与质量控制

　　Construction technology and quality control of on-site cold recycling base (sub base) for asphalt pavement

　　摘要：文章主要介绍了二级公路沥青路面就地冷再生基层(底基层)从人员机械配置、旧路面材料分析、补强、破碎拌和、整形、碾压、养生，到施工质量控制。

　　Abstract: The article mainly introduces the on-site cold recycling base (subbase) of asphalt pavement of second-class highway from personnel and machinery allocation, old pavement material analysis, reinforcement, crushing and mixing, shaping, rolling, curing, to construction quality control.

　　关键词：沥青路面；基层；施工技术

　　Keywords: Asphalt pavement; the basic level; construction technology

　　沥青路面就地冷再生基层(底基层)技术是指把旧沥青路面面层、基层掺入一定数量、符合标准要求的水泥(或稳定剂、集料)，按照设定的厚度，用冷再生机进行破碎拌和处理后，整形、碾压，并经后期养生，使其达到设计路面基层或底基层技术指标要求的施工工艺。该工艺具有施工简便快速、充分利用旧路面层材料、保护环境、质量可靠、施工进度快、经济效益好等优点。笔者曾根据路网改造项目的实际情况，通过细致的观察、研究，对其施工工艺和质量控制进行了探索。为此对冷再生施工主要工艺和质量控制要点归纳如下。

　　The on-site cold recycling base (sub base) technology for asphalt pavement refers to the construction process of adding a certain amount of cement (or stabilizer, aggregate) that meets the standard requirements to the old asphalt pavement surface layer and base, crushing and mixing it with a cold recycling machine according to the set thickness, shaping and rolling it, and later curing it to meet the technical indicators of the designed pavement base or sub base. This process has the advantages of simple and fast construction, full utilization of old pavement layer materials, environmental protection, reliable quality, fast construction progress, and good economic benefits. Based on the actual situation of the road network renovation project, the author has explored its construction technology and quality control through detailed observation and research. The main processes and quality control points for cold recycling construction are summarized as follows.

　　1　施工准备

　　1. Construction preparation

　　1.1  人员配置

　　1.1 Personnel Configuration

　　除冷再生机组人员外，需另配试验检测人员2人，技术负责人1人，工人10～15人。

　　In addition to the personnel of the cold regeneration unit, 2 additional testing and inspection personnel, 1 technical leader, and 10-15 workers are required.

　　1.2  机械配置

　　1.2 Mechanical Configuration

　　冷拌再生机1台，洒水车3～4台，50t振动压路机1台，18t～21 t光轮压路机2台，平路机1台。

　　One cold mix recycling machine, 3-4 sprinkler trucks, one 50t vibratory roller, two 18t~21t smooth wheel rollers, and one leveling machine.

　　1.3  再生机组开工前准备

　　1.3 Preparation before starting the regeneration unit

　　对再生机及其配套的所有机械设备进行全面检查，检查再生机械操作人员是否已掌握所有与再生施工有关的数据，所有再生施工开始程序是否均已清楚。

　　Conduct a comprehensive inspection of the regeneration machine and all its supporting mechanical equipment, check whether the operators of the regeneration machine have mastered all the data related to regeneration construction, and whether all the procedures for starting regeneration construction are clear.

　　1.4  旧路面缺陷修复

　　1.4 Repair of old road surface defects

　　对于局部翻浆地段进行换填砂砾进行夯实碾压，对于路肩下沉、路面偏拱及旧路坑槽处理，均采用填补砂砾修整。

　　For areas with local mud erosion, replacement with gravel is carried out for compaction and rolling. For the treatment of road shoulder subsidence, road surface arch deviation, and old road potholes, gravel filling is used for repair.

　　1.5  旧路面混合料分析

　　1.5 Analysis of old pavement mixture

　　通过对旧路结构的现场调查，对旧路结构层厚度不足路段，应加铺砂砾以保证再生层厚度。冷再生机现场破碎未掺加水泥的旧路面，由试验人员就地均衡取料，通过对拌和料的筛分及多次击实试验，确定粒料的最大干密度、最佳含水量。进行无侧限抗压强度试验确定掺加的水泥剂量。

　　Through on-site investigation of the old road structure, it was found that in sections where the thickness of the old road structure layer is insufficient, gravel should be added to ensure the thickness of the recycled layer. The cold recycling machine crushes the old road surface without adding cement on site, and the test personnel evenly take the materials on site. Through screening and multiple compaction tests of the mixed materials, the maximum dry density and optimal moisture content of the aggregates are determined. Conduct unconfined compressive strength tests to determine the amount of cement to be added.

　　1.6  水泥摊铺在纵向每隔10m放出施工控制线

　　1.6 Construction control lines shall be set out every 10m longitudinally for cement paving

　　钉上钢筋桩并挂线，利于冷再生机边线控制，经室内试验确定冷再生底基层水泥用量为4％，施工过程中按5％控制。摊铺水泥前按路线前进方向每10m为一格，计算出每一格水泥用量，然后人工按每格摊铺几袋水泥，将水泥均匀布满方格，确保水泥布撒均匀、一致、等厚。原有路缘石待路面冷再生碾压成型后再拆除。

　　Nail steel reinforcement piles and hang lines to facilitate the control of the cold recycling machine edge. After indoor testing, it was determined that the cement dosage for the cold recycling base layer is 4%, and during the construction process, it is controlled at 5%. Before laying cement, every 10m in the direction of the route, calculate the amount of cement used for each grid. Then, manually lay several bags of cement per grid, evenly distribute the cement throughout the grid, and ensure that the cement is evenly, uniformly, and of equal thickness. The original curbstones will be removed after the road surface is cold recycled and compacted into shape.

　　2　旧路面再生破碎拌和

　　2. Recycling, crushing, and mixing of old road surfaces

　　冷再生段采用等厚法施工，按全路宽12 m计算，考虑到半幅施工的搭接问题，所以在第一次半幅施工时，加宽50 cm进行施工，利于另半幅冷再生的搭接施工。冷再生机一次破碎宽度为2.5 m，半幅路面以行进3次完成。工作时，冷再生机需一辆洒水车紧跟作业，其余2～3辆洒水车配合保证拌和用水，拌和过程中按试验的最佳含水量控制加水，拌和行进速度7m／min～10m／min。

　　The cold recycling section is constructed using the equal thickness method, calculated based on a total road width of 12 meters. Considering the overlapping problem of half width construction, the first half width construction is widened by 50 cm to facilitate the overlapping construction of the other half width cold recycling. The crushing width of the cold recycling machine is 2.5 meters, and half of the road surface is completed by traveling three times. During operation, the cold recycling machine requires one sprinkler truck to closely follow the operation, and the other 2-3 sprinkler trucks to cooperate to ensure the use of mixing water. During the mixing process, water should be added according to the optimal water content of the test, and the mixing speed should be 7m/min to 10m/min.

　　考虑到水泥的初凝时间，以及各道工序的衔接问题，以100m实施工长度为限，当冷再生机单幅破碎100m后，返回准备第二幅进行的当中，对刚完成的100m进行稳压，然后平地机进行刮平,501振动压路面进行振动压实，直至达到规定的压实度，平整度按规范要求控制。

　　Considering the initial setting time of cement and the connection issues of each process, the construction length is limited to 100m. After the cold recycling machine crushes 100m in a single section, it returns to the middle of preparing for the second section to stabilize the just completed 100m. Then, the grader is used for leveling, and the 501 vibration roller is used for vibration compaction of the road surface until the specified compaction degree is achieved. The flatness is controlled according to the specifications.

　　3　再生层整形

　　3 Regenerative layer plastic surgery

　　半幅路段拌和完毕后，先用50 t振动压路机稳压2～3遍后。用平地机初步整平，测量人员根据设计纵断高程和横坡度，每10m为一断面分左中右3个点测出高程，按1.05-1.1的松铺系数，人工找出基准点，高程不足时及时调节富裕路段材料，高出段及时用平地机刮平。通过旧路整形达到“调坡”、“调拱”的目的，且保证平整度满足设计要求。要求整平精度要高。确保平整度和纵断面高程、横坡度符合设计。施工中。按“宁刮勿补”的原则，严禁“薄层找补”。若找补厚度过薄，找补前先将稳压后的局部低洼处用齿耙将表层5 cm耙松，再行找补。确保碾压成型一致，不起皮、不松散、无离析现象。

　　After the half section is mixed, use a 50 ton vibratory roller to stabilize the pressure for 2-3 times first. Preliminarily level with a grader, and the surveyors measure the elevation at three points on the left, middle, right, and right sides of a section every 10 meters based on the designed longitudinal elevation and cross slope. Using a loose paving coefficient of 1.05-1.1, manually find the reference point. If the elevation is insufficient, adjust the material of the surplus section in a timely manner, and use a grader to level the elevated section in a timely manner. By reshaping the old road, the purpose of "slope adjustment" and "arch adjustment" can be achieved, while ensuring that the flatness meets the design requirements. High leveling accuracy is required. Ensure that the flatness, longitudinal elevation, and cross slope comply with the design. During construction. According to the principle of "better scraping than repairing", it is strictly prohibited to "repair thin layers". If the thickness of the repair is too thin, first loosen the surface 5 cm of the locally low-lying area after stabilizing with a toothed rake before repairing. Ensure consistent compaction molding, without peeling, looseness, or segregation.

　　4　再生层碾压

　　4. Rolling of recycled layer

　　再生层整形完成及时碾压，检测含水量必须等于或略大于最佳含量。整形后检测各项标高符合设计要求，碾压顺序为用振动压路机振压3遍，18 t～21 t光轮压路机静压1～2遍，表面要保证平整、湿润。碾压后外观平整，无明显轮迹，检测压实度达到规范要求。

　　The regeneration layer should be compacted in a timely manner after shaping, and the moisture content detected must be equal to or slightly higher than the optimal content. After plastic surgery, all elevations are checked to meet the design requirements. The rolling sequence is to use a vibratory roller for 3 times of vibration, and an 18 ton to 21 ton smooth wheel roller for 1-2 times of static pressure. The surface should be ensured to be smooth and moist. After compaction, the appearance is smooth without obvious wheel marks, and the compaction degree meets the standard requirements.

　　使用50 t双幅/双频振动压路机的时，要确保：初压时使用高幅，低频振动模式，这将保证整个深度内具有良好的压实。复压采用低幅／高频，这将保证对铺层上部的良好压实。

　　When using a 50 ton double amplitude/dual frequency vibratory roller, it is important to ensure that high amplitude and low frequency vibration modes are used for initial compaction, which will ensure good compaction throughout the entire depth. The re compaction adopts low amplitude/high frequency, which will ensure good compaction of the upper part of the paving layer.

　　5　再生层养生

　　5 Regenerative Layer Health Preservation

　　碾压检测合格后及时洒水养生，养生期内中断所有交通，杜绝洒水车以外的任何车辆进入，养生期不少于7 t，要使冷再生基层表面始终保持湿润，做到每天及时洒水，专人看管，确保再生层不因洒水养生不当产生损坏。

　　After passing the compaction inspection, water should be sprayed in a timely manner for curing. During the curing period, all traffic should be interrupted and any vehicles other than sprinkler trucks should be prohibited from entering. The curing period should not be less than 7 tons. The surface of the cold regeneration base should be kept moist at all times, and water should be sprayed in a timely manner every day with a dedicated person to supervise to ensure that the regeneration layer is not damaged due to improper watering and curing.

　　6　质量控制要点

　　6 Quality Control Points

　　再生处理旧路面宽12 m，外掺32.5缓凝水泥剂量为4％；冷再生底基层再生拌和厚度20 cm，其中5 cm为整平层，整平压实后保证冷再生底基层再生厚度1 cm～5 cm的设计要求，水稳砂砾底基层强度应达到1.5 MPa以上，压实度及平整度必须达到二级公路底基层要求。

　　Recycled old road surface with a width of 12 meters and an external dosage of 32.5% retarding cement of 4%; The recycled mixing thickness of the cold recycled subbase is 20 cm, of which 5 cm is the leveling layer. After leveling and compaction, the design requirements of 1 cm~5 cm of the recycled thickness of the cold recycled subbase shall be guaranteed. The strength of the water stabilized gravel subbase shall reach more than 1.5 MPa, and the compactness and flatness must meet the requirements of the subbase of second-class highway.

　　总之，采用沥青路面就地冷再生技术进行基层、底基层施工实践，从工期效益、综合经济效益、社会效益方面，都具明显的优点与显著的推广应用价值。

　　In summary, the use of on-site cold recycling technology for asphalt pavement in the construction of base and sub base layers has obvious advantages and significant promotion and application value in terms of project schedule benefits, comprehensive economic benefits, and social benefits.

　　(1)它不仅可以节约能源和资源，降低材料费、人工费，节省运输费，几乎可以不受阴湿或低温季节影响，可以适应严冬以外各种施工季节，改善了施工条件、减少了环境污染、有益于环境保护，大大加快施工进度而缩短工期。

　　(1) It can not only save energy and resources, reduce material and labor costs, save transportation costs, but also be almost unaffected by humid or low-temperature seasons. It can adapt to various construction seasons outside of severe winter, improve construction conditions, reduce environmental pollution, and be beneficial to environmental protection, greatly accelerating construction progress and shortening the construction period.

　　(2)采用就地冷再生技术进行基层或底基层施工。通过拌和、整形、碾压后，可以解决旧路偏拱，还可对纵坡进行微调。

　　(2) Adopting on-site cold recycling technology for base or sub base construction. After mixing, shaping, and rolling, the problem of old road arch deviation can be solved, and the longitudinal slope can also be fine tuned.

　　(3)减少了基层材料用量，这对于天然砂砾级配不达设计标准地区尤为重要。

　　(3) Reducing the amount of base materials is particularly important for areas where the natural sand and gravel grading does not meet the design standards.

　　(4)施工质量有保证，人为因素影响少，特别是对路基原有强度保持良好，与开挖比较，减少了扰动。

　　(4) The construction quality is guaranteed with minimal human factors, especially in maintaining the original strength of the roadbed, which reduces disturbance compared to excavation.