就地冷再生施工工艺及质量控制

　　On site cold recycling construction technology and quality control

　　摘要：冷再生技术与传统道路维修相比，节能、环保，同时具有明显的社会和经济效益，越来越在道路维修中得到应用；冷再生施工工艺流程及质量控制。关键词：冷再生 、 施工工艺、质量控制

　　Abstract: Compared with traditional road maintenance, cold recycling technology is energy-saving, environmentally friendly, and has significant social and economic benefits, and is increasingly being applied in road maintenance; Cold recycling construction process and quality control. Keywords: cold recycling, construction technology, quality control

　　近几年来，随着我国经济持续快速发展，交通量的迅猛增长，道路通车里程逐年增加，加速了道路的各种病害，大大缩短了道路维修养护的间隔时间，道路养护维修任务也来越重。与以往传统的道路维修方法相比，冷再生施工技术可缩短工期、提高作业效率，完全利用废旧材料，节省施工成本，对交通的干扰最小，而且符合现代社会对于环保节能方面的要求，具有明显的经济效益和社会效益，越来越在道路维修中得到应用。　　旧沥青路面冷再生技术是指把旧沥青路面面层、基层加入一定规格、数量的集料、水泥后, 按设定的厚度, 用冷再生机械设备进行破碎、加水、拌和，并完成整形、碾压、后期养生等一系列流程后，使其达到新建路面基层或底基层技术要求的施工工艺。

　　In recent years, with the sustained and rapid development of China's economy and the rapid growth of traffic volume, the mileage of roads has been increasing year by year, accelerating various road diseases and greatly shortening the interval between road maintenance and repair. The task of road maintenance and repair has also become increasingly heavy. Compared with traditional road maintenance methods in the past, cold recycling construction technology can shorten the construction period, improve work efficiency, fully utilize waste materials, save construction costs, minimize interference with traffic, and meet the requirements of modern society for environmental protection and energy conservation. It has obvious economic and social benefits and is increasingly being applied in road maintenance. The cold recycling technology for old asphalt pavement refers to the construction process of adding a certain specification and quantity of aggregate and cement to the surface and base of the old asphalt pavement, using cold recycling machinery and equipment to crush, add water, mix, and complete a series of processes such as shaping, rolling, and later curing according to the set thickness, so as to meet the technical requirements of the new pavement base or sub base.

　　一、施工准备  1、工程开工前，应保证设备机具完好并满足施工需要。旧路面现场应清扫干净，不得有尘土、杂草、树根及积水，并对旧路较为严重的网裂，明显沉陷、坑槽等病害采取有效措施进行处理。

　　1、 Construction Preparation 1. Before the commencement of the project, it is necessary to ensure that the equipment and machinery are in good condition and meet the construction needs. The old road surface should be cleaned up on site, without dust, weeds, tree roots, and standing water. Effective measures should be taken to deal with serious defects such as mesh cracks, obvious subsidence, potholes, etc. on the old road.

　　2、在原路面上恢复中线，直线段每15m-20m设一桩，平曲线段每10m-15m设一桩。每隔15m左右在原路面上挖一小洞，使洞底标高与预定的再生层底面标高相同，并在洞底做一标记，以控制翻松深度。

　　2. Restore the centerline on the original road surface, with one pile set every 15m-20m for straight sections and every 10m-15m for flat curved sections. Dig a small hole on the original road surface every 15m or so, so that the bottom elevation of the hole is the same as the predetermined elevation of the recycled layer bottom, and make a mark at the bottom of the hole to control the loosening depth.

　　3、材料要求

　　3. Material requirements

　　现场铣刨拌合几段未加入集料和水泥的旧路面，实验室分别均衡取料进行筛分试验。试验结果应满足：最大粒径不能超过40mm，粒径为4.75mm的通过率不小于40%，粒径为0.6mm的通过率不小于10%，粒径为0.075mm的通过率宜在3%~20%之间。如果旧料级配不能满足上述要求时，应加入一定规格、数量的新集料进行调配。水泥采用强度等级为32.5级的路用普通硅酸盐水泥，初凝时间3h以上和终凝时间较长(宜在6h以上)的水泥。水采用不含有害物质的水或饮用水。

　　On site milling and mixing of several sections of old road surface without adding aggregates and cement, the laboratory evenly takes materials for screening tests. The test results should meet the following requirements: the maximum particle size should not exceed 40mm, the pass rate for particles with a size of 4.75mm should not be less than 40%, the pass rate for particles with a size of 0.6mm should not be less than 10%, and the pass rate for particles with a size of 0.075mm should be between 3% and 20%. If the old material grading cannot meet the above requirements, a certain specification and quantity of new aggregate should be added for blending. The cement used is ordinary Portland cement with a strength grade of 32.5, and cement with an initial setting time of more than 3 hours and a final setting time of more than 6 hours (preferably more than 6 hours). Use water that does not contain harmful substances or drinking water.

　　4、配合比

　　4. Mix ratio

　　对符合级配要求的混合料进行五个不同水泥剂量的击实试验，确定混合料的最大干密度、最佳含水量等数据，通过无侧限抗压强度试验确定满足设计强度要求所需的水泥剂量。 5、铺筑试验段：

　　Conduct five different cement dosage compaction tests on the mixture that meets the grading requirements to determine the maximum dry density, optimal moisture content, and other data of the mixture. Determine the required cement dosage to meet the design strength requirements through unconfined compressive strength tests. 5. Paving test section:

　　配合比完成后，即可进行试验段施工；试验路段长度宜为100m~200m。试验段施工应包括以下内容：1）计算每平方米水泥用量，并确定水泥摆放的纵、横向间距；2）冷再生机的工作参数：铣刨、破碎的深度；行进的速度；刀具的转速等；3）再生机每行进1米的用水量及供水车的数量；4）压实工艺主要参数：机械组合；压路机的规格、碾压遍数、碾压速度；碾压时含水量的允许偏差；5）优化后的施工组织方案及工艺等。在以上内容中，尤其是确定铣刨、破碎的深度往往被忽视。通过现场施工中的量测得出，再生后的底基层厚度大于铣刨、破碎的深度。所以，试验段施工后必须总结出冷再生底基层厚度与铣刨、破碎的深度的比值。否则，将使再生混合料中的水泥剂量偏小。

　　After the completion of the mix proportion, the construction of the test section can be carried out; The length of the test section should be between 100m and 200m. The construction of the experimental section should include the following contents: 1) Calculate the cement consumption per square meter and determine the longitudinal and transverse spacing of cement placement; 2) Working parameters of the cold recycling machine: milling and crushing depth; The speed of movement; The rotational speed of the cutting tool, etc; 3) The water consumption and number of water supply vehicles for each meter traveled by the regeneration machine; 4) Main parameters of compaction process: mechanical combination; The specifications, number of rolling passes, and rolling speed of the road roller; Allowable deviation of moisture content during compaction; 5) Optimized construction organization plan and process, etc. In the above content, especially determining the depth of milling and crushing is often overlooked. According to measurements taken during on-site construction, the thickness of the regenerated subgrade is greater than the depth of milling and crushing. Therefore, after the construction of the experimental section, it is necessary to summarize the ratio of the thickness of the cold recycled subbase to the depth of milling and crushing. Otherwise, it will result in a lower cement dosage in the recycled mixture.

　　二、冷再生施工工艺1、清除原路面上的杂物，根据试验段确定的每平方米水泥用量及水泥摆放的纵、横向间距摆放水泥，并将水泥均匀摊铺。

　　2、 Cold recycling construction process 1. Remove debris from the original road surface, place cement according to the determined cement dosage per square meter and the vertical and horizontal spacing of cement placement in the test section, and evenly spread the cement.

　　2、拌合

　　2. Mixing

　　冷再生机对原路面进行旧路材料和水泥充分加水拌和，拌合过程中试验人员要随时检测混合料的含水量，保证控制在碾压时含水量的允许偏差范围内。拌和时再生机必须缓慢、均匀、连续地进行再生作业，不得随意变更速度或者中途停顿，行走速度控制在5m/min-10 m/min。

　　The cold recycling machine thoroughly mixes old road materials and cement with water on the original road surface. During the mixing process, the testing personnel should constantly check the moisture content of the mixture to ensure that it is controlled within the allowable deviation range of moisture content during rolling. During mixing, the regeneration machine must carry out regeneration operations slowly, evenly, and continuously, without arbitrarily changing the speed or stopping halfway. The walking speed should be controlled between 5m/min and 10m/min.

　　3、摊铺

　　3. Spread out

　　就地冷再生机具具备摊铺装置的在再生过程中完成摊铺。当发现摊铺出的混合料出现明显的离析、波浪、裂缝、托痕时，应降低再生和摊铺速度。

　　The on-site cold recycling equipment equipped with paving devices completes paving during the recycling process. When obvious segregation, waves, cracks, and support marks are found in the paved mixture, the regeneration and paving speed should be reduced.

　　就地冷再生机不具备摊铺装置的，使用平地机进行摊铺。（1）用轻型钢轮压路机紧跟再生机组快速初压，每次碾压从施工段起点开始，至再生机边缘上，碾压宽度应超过该幅再生宽度，碾压2-3遍。（2）完成1各作业段的再生和初压后，用平地机整形1遍。（3）用平地机整形1-2遍，达到规范的坡度和路拱，无明显的再生机轮迹和粗细离析现象。

　　If the on-site cold recycling machine does not have a paving device, a grader should be used for paving. (1) Use a lightweight steel wheel roller to quickly perform initial compaction following the regeneration unit. Each compaction should start from the starting point of the construction section and reach the edge of the regeneration machine. The compaction width should exceed the regeneration width, and the compaction should be done 2-3 times. (2) After completing the regeneration and initial pressing of each homework section, use a grader to shape it once. (3) Use a grader to shape 1-2 times to achieve the standard slope and road arch, without obvious regeneration machine wheel marks or coarse and fine separation.

　　5、整形

　　5. Plastic surgery

　　混合料拌合均匀后，用平地机初步整形。在直线段，平地机由两侧向路中心进行刮平；在平曲线段，平地机由内侧向外侧进行刮平。必要时，再返回刮一遍。用平地机或压路机立即在初平的路段上快速碾压一遍，以暴露潜在的不平整。对于局部低洼处，应用齿耙将其表层5cm以上耙松，并用新拌的混合料进行找平。再用平地机整形一次，应将高处料直接刮出路外，不应形成薄层贴补现象。每次整形都应达到规定的坡度和路拱，并应特别注意接缝必须顺适平整。

　　After the mixture is evenly mixed, use a grader to preliminarily shape it. In the straight section, the grader flattens from both sides towards the center of the road; On the flat curve section, the grader flattens from the inside to the outside. If necessary, go back and scrape again. Immediately use a grader or roller to quickly roll over the initially leveled road section to expose potential unevenness. For locally low-lying areas, use a toothed rake to loosen the surface layer by more than 5cm and level it with freshly mixed material. After using a grader for shaping, the high material should be directly scraped out of the road without forming a thin layer of patching. Each plastic surgery should achieve the specified slope and road arch, and special attention should be paid to ensuring that the joints are smooth and even.

　　6、碾压

　　6. Rolling and crushing

　　碾压遵循先轻后重，先慢后快的原则，压路机在结构层全宽范围内进行碾压。直线段和不设超高的平曲线段由两侧向中心碾压；设平曲线的超高段，由低处向高处碾压。碾压时，轮迹应重叠1/2轮宽，碾压速度前两遍宜采用1.5km/h~1.7km/h，以后宜采用2.0km/h~2.5km/h。碾压过程中，再生混合料表面应始终保持湿润，如水分蒸发过快，可及时补洒少量的水，但严禁洒水过量。如有“弹簧”、松散、起皮现象，应及时翻开加适量水泥重新拌合，使其达到质量要求。在施工过程中，必须保证再生混合料从加水拌合到碾压成型的时间不应超过水泥的初凝时间。碾压时注意错轴宽度，并由路边向路中心依次碾压，终压之后；冷再生层应平整光滑，表面有水浆渗出，注意终压完成时间不能超过水泥终凝时间。碾压完成后灌砂法测定压实度，保证密实度满足设计要求。　　7、接缝处理：施工过程中产生的纵缝和横缝均采用搭接施工，一般纵缝搭接10cm，纵缝的位置应尽量避开快、慢车道上车辆行驶的轮迹；横缝视情况而定一般搭接1-2m；在搭接部分应足量撒铺水泥重新拌和、碾压，以确保接缝处的工程质量。

　　The compaction follows the principle of light first and then heavy, slow first and then fast, and the roller is used to compact the entire width of the structural layer. Straight sections and flat curved sections without superelevation are rolled from both sides towards the center; Set the super-high section of the horizontal curve and roll it from low to high. When rolling, the wheel tracks should overlap by half the wheel width. The rolling speed for the first two passes should be between 1.5km/h and 1.7km/h, and for subsequent passes, it should be between 2.0km/h and 2.5km/h. During the rolling process, the surface of the recycled mixture should always be kept moist. If the water evaporates too quickly, a small amount of water can be added in a timely manner, but excessive watering is strictly prohibited. If there are "springs", looseness, or peeling phenomena, they should be promptly opened and mixed with an appropriate amount of cement to meet the quality requirements. During the construction process, it is necessary to ensure that the time from adding water to compacting the recycled mixture should not exceed the initial setting time of the cement. Pay attention to the width of the wrong axis when rolling, and roll from the roadside to the center of the road in sequence, after the final rolling; The cold regeneration layer should be flat and smooth, with water slurry seeping out from the surface. It is important to note that the final pressing time should not exceed the final setting time of the cement. After compaction, the sand filling method is used to determine the compaction degree to ensure that it meets the design requirements. 7. Joint treatment: Both longitudinal and transverse joints generated during the construction process are constructed by overlapping, with a general overlap of 10cm for longitudinal joints. The position of the longitudinal joints should avoid the wheel tracks of vehicles driving on fast and slow lanes as much as possible; The horizontal joint is generally overlapped by 1-2m depending on the situation; sufficient cement should be spread and re mixed and compacted at the overlapped part to ensure the engineering quality of the joint.

　　8、养生：碾压成形四小时后(视气温情况)，可以用潮湿的帆布和其他合适的潮湿材料覆盖。在整个养生期间，都应保持覆盖材料处于潮湿状态。也可用水车在冷再生层上直接淋水养护。在七天内禁止放行交通，全天候养生，始终保持表面湿润。

　　8. Health Preservation: After four hours of compaction (depending on the temperature), it can be covered with damp canvas and other suitable damp materials. Throughout the entire health preservation period, the covering material should be kept in a moist state. Water trucks can also be used to directly spray water on the cold regeneration layer for maintenance. Prohibit traffic for seven days, maintain health around the clock, and keep the surface moist at all times.

　　三、质量控制与检测1、平整度：终压完毕后，每200延米2处，每处连续10尺，允许误差≤10mm；

　　3、 Quality Control and Testing 1. Flatness: After the final pressing is completed, there are 2 points every 200 linear meters, with each point being continuous for 10 feet, and the allowable error is ≤ 10mm;

　　2、纵断高程：每20延米1点，允许偏差±10mm；

　　2. Vertical elevation: 1 point per 20 linear meters, with an allowable deviation of ± 10mm;

　　3、横坡度：每100延米3处，允许偏差±0.3%；

　　3. Cross slope: 3 points per 100 linear meters, with an allowable deviation of ± 0.3%;

　　4、厚度：施工过程中派专人随时检查。

　　4. Thickness: Assign a dedicated person to inspect at any time during the construction process.

　　5、压实度：终压完毕后，用灌砂法每车道每公里检查1处；

　　5. Compaction degree: After the final compaction is completed, check one point per kilometer per lane using the sand filling method;

　　6、7天无侧限抗压强度： 试件6天标准养生（温度20±2℃，相对湿度≥95%），浸水1天测抗压强度。

　　6. 7-day unconfined compressive strength: The specimen is subjected to standard curing for 6 days (temperature 20 ± 2 ℃, relative humidity ≥ 95%), and the compressive strength is measured after being immersed in water for 1 day.

　　总之，只有加强冷再生各个环节的质量控制，优化冷再生施工工艺，才能保证冷再生施工质量的要求。

　　In short, only by strengthening the quality control of each link in cold recycling and optimizing the cold recycling construction process can the requirements of cold recycling construction quality be guaranteed.