Pavement Design And Quality Control For Xiaolangdi Special Road Reconstruction Engineering

Concrete pavement is widely used in road construction in our country for its high strength, gooddurability and long service life, easily obtained and low demand of raw materials. Concrete pavement facesproblems of demolition or reconstruction when it is at or more than the end of service life. Concretepavement is difficult to dismantle, and removed old concrete plates not only waste resources but alsooccupy land. Therefore, overlaying reinforcing layer or the rubblization technology can be used to the oldconcrete pavement. Rubblization technology can eliminate the overlay reflective cracking thoroughly. Butas an American technology, with no equipments and technology transfer, only with project contracting,rubblization technology can cost as high as35to40yuan per square meter, causing the general use isunrealistic in our country. At present, for the old concrete road reconstruction project, overlaying asphaltlayer on old concrete board is the mostly used technology.In this paper, a set of design theory about old concrete road surface reconstruction is presented basedon the project of Xiaolangdi special highway reconstruction project. The entire design process focuses onthe use of renewable resources, adhering to the concept of economic environment. The technical conditionof the old concrete pavement was evaluated by PCI and DBL based on the analysis of the structure,damage, diseases and carrying capacity for the old concrete pavement. And combined with the currenttraffic situation, the conclusion of reconstruction scheme for the old concrete road was given.Reconstruction methods for the old concrete pavement direct paving, crack and seat, broken treatment andrubblization technology were introduced and analyzed. Combined with the situation of Xiaolangdi specialroads, for the elevation unrestricted pavement section, the old concrete pavement, broken by multiple-headbreakers, was used to be the sub-base of the new pavement structure; for the elevation restricted pavementsection, the old concrete pavement was removed, and new pavement structure was paved after.The material property of the mixtures on the surface and base layers was analyzed. For the practicalproject, paving a leveling layer and cement and applying fly ash stabilized crushed-stones base waspresented to reduce the reflection crack. Aiming at the blank of concrete and fly ash stabilizedcrushed-stones in the standards of China, a "10%fly ash" was applied referring to mixture design methodof concrete stabilized macadam and lime stability crushed stones and drawing lessons from previousexperimental study results. By using rubber modified asphalt mixtures on the surface layer, anenvironmental protection effect was obtained; the deformation resisting capability of the asphalt pavementwas improved; and the traffic noise was reduced at the same time. Replacing the resilient module of soilwith the equivalent modulus of elasticity at the top of the broken concrete plate, the thickness of theoverlay on the broken concrete pavement can be calculated using the calculation method of the newly-builtpavement. Construction technology and main points of the old concrete pavement and related preparatorywork and control requirements etc. were given, which provide an important theoretical basis and technicalsupport for the old concrete crushing process.