Construction quality control of cold recycling of old pavement

　　近幾年來，我國公路發展非常迅速，隨著交通量的日益增加，大量公路已接近設計使用年限，需要進行大修或改造，現場冷再生技術是適宜的維修或改造方式。現場冷再生技術，不僅可以節約能源，降低施工成本，更有益于環境保護。結合改建工程，采用現場冷再生處理舊路面面層及基層，取得良好效果。冷再生基層是指把原路面的舊面層、基層用專用路面再生機，按照一定的厚度進行破碎處理，同時加入一定規格和數量的新集料、粘合劑（水泥等），按一定配合比拌和，之后進行整形、碾壓，使其恢復達到路面基層或底基層技術要求的施工工藝。現場冷再生技術，不僅可以節約能源，降低施工成本，更有益于環境保護。下面就于改建工程現場冷再生技術分析如下：

　　In recent years, China's highway development is very rapid, with the increasing traffic volume, a large number of roads are close to the design service life, and need to be overhauled or transformed. The cold regeneration technology on site is the appropriate maintenance or transformation method. On site cold recycling technology can not only save energy, reduce construction cost, but also benefit environmental protection. Combined with the reconstruction project, cold recycling is used to treat the surface and base of old pavement, and good results are achieved. Cold recycled base course refers to the construction technology that the old surface course and base course of the original pavement are crushed with a special pavement regenerator according to a certain thickness, and a certain specification and quantity of new aggregate and binder (cement, etc.) are added, mixed according to a certain mix proportion, and then reshaped and rolled to make it recover to meet the technical requirements of pavement base or subbase. On site cold recycling technology can not only save energy, reduce construction cost, but also benefit environmental protection. The following cold regeneration machine rental on the reconstruction project site cold regeneration technology analysis is as follows:

　　1、再生老路概況

　　1. Overview of old road regeneration

　　改建工程全長29.374km，其中k0+000-k8+850段進行冷再生施工，寬7m。原路面面層為3cm瀝青碎石，基層為15cm石灰穩定土，冷再生處理舊路18cm。

　　The total length of the reconstruction project is 29.374km, in which the K0 + 000-k8 + 850 section is constructed by cold recycling, with a width of 7m. The surface course of the original pavement is 3cm asphalt macadam, the base course is 15cm lime stabilized soil, and the cold recycling treatment of the old road is 18cm.
               

　　2、舊路面冷再生施工質量控制

　　2. Construction quality control of cold recycling of old pavement

　　鑒于目前冷再生試驗無我國規定，本次試驗參照《公路土工試驗規程》（JTJ051-93）和《公路工程無機結合料穩定材料試驗規程》（JTJ057-94）進行。

　　In view of the fact that there is no national regulation for cold recycling test at present, the test is carried out according to "highway geotechnical test specification" (jtj051-93) and "highway engineering inorganic binder stabilized material test specification" (JTJ057-94).

　　（1）改建工程冷再生技術為舊路面面層、基層再生為基層，設計強度1.5MPa。通過對現有材料進行分析，采用摻加粘合劑（水泥）的方法，保證基層強度。

　　(1) The cold recycling technology of the reconstruction project is that the old pavement surface layer and the base layer are recycled into the base course, and the design strength is 1.5MPa. Through the analysis of the existing materials, the method of adding binder (cement) is adopted to ensure the strength of the base course.

　　（2）選擇水泥的摻配比例為百分之3、百分之4、百分之5、百分之6。通過擊實試驗、無側限抗壓強度試驗確定水泥的摻入量。擊實、無側限抗壓強度得出試驗結果。

　　(2) The mixing proportion of cement is 3%, 4%, 5% and 6%. Through compaction test and unconfined compressive strength test, the amount of cement added is determined. The test results are obtained by compaction and unconfined compressive strength.

　　（3）經試驗室確定冷再生摻加水泥用量百分之5，施工過程中按百分之6控制，進行200m試驗路段施工，其壓實度、強度等各項指標均達到設計要求。

　　(3) According to the laboratory determination, the amount of cement mixed with cold recycling is 5%, and the control rate is 6% in the construction process. The construction of 200m test section is carried out. The compactness, strength and other indicators meet the design requirements.