Construction quality control of cold recycling of old pavement
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. Overview of old road regeneration
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. Construction quality control of cold recycling of old pavement
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) 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) 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) 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.
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