Study On Pavement Reconstruction And Construction Technology Of Changda Highway

In recent years, many regions of our country were beginning to rehabilitate and renovate huge amounts of old cement concrete pavement ,the main measure is resurfacing asphalt cncrete overlay, to improve performance of the original cement concrete pavement, increase the comfortability of the road, at the same time take full advantage of the residual strength of the old cement concrete pavement.And using asphalt overlay to rehabilitate the old cement concrete pavement has the advantage of short construction period, small traffic impact,less investment, driving comfort, etc., so it has become a simple and effective restoration measures at home and abroad.This article used the old cement concrete pavement of Expressway to Jingyue section of Changda highway as test section , closely linked the practice of its renovation project, the main research contents include the following:1,Structure and design theory of asphalt concrete overlay on old cement concrete pavementSummarize and analyze the characteristics of asphalt layer on the old cement concrete pavement, and discuss the current domestic and foreign design theories and methods.2,Analysis and evaluation of the service condition of the old cement concrete pavementDetailedly introduce the survey and evaluation methods of the pavement damage state, to provide theoretical basis for a reasonable assessment of road conditions and reinforcement design. Through the damage survey of the cement concrete pavement of Changda highway, as well as the results of design and construction, etc., analyze the damage form and main reason of the old road surface of this project. According to the form of the disease put forward the corresponding measures.3,Overlay scheme and material design of asphalt layerIn connected with the investigation and assessment results of the old cement concrete pavement of Changda highway, refer to the typical structure of domestic asphalt overlayer, bring forward the renovation plan of asphalt overlayer. Raw materials for the project has been tested and advance the reasonable gradation of SMA-16, design the mixture proportion in accordance with the Marshall method.4,Construction technology and quality control of asphalt overlayer SMASummarize and discuss the construction technology, construction attentions and quality control of the mixture mixing, paving, roller etc. of the modified asphalt mixture of SMA-16 asphalt overlayer, provide reference to the construction of the asphalt overlayer on the old cement concrete pavement.Through detailed and thorough analysis and evaluation study of the old cement concrete pavement of Expressway to Jingyue section of Changda highway ,research the old road treatment, overlay and renovation technology ,put forward the structure design plan and construction technology of asphalt mixture overlayer on the old cement concrete pavement,come to the following conclusions:1,From a structural point of view, the asphalt overlay on old cement concrete pavement is a special kind of pavement structure, and its stress-strain characteristics has a greater difference from the general elastic layered system.Since the existence of seams and cracks ,under the external loads, asphalt concrete overlayer increases in complex three-dimensional stress state, and the prevention and control of reflection cracks in asphalt overlayer is designed to focus on.2,The damage condition of the old cement pavement was very complicated and has large variability, increases the impact variables which needed to consider in the overlayer design, and design parameters are also difficult to determine correct. About overlaying asphalt layer on the old cement concrete, there has not mature design method in our country at present, but the major factor which considered in the design of asphalt overlayer should be the strength of the old cement pavement structure and the prevention of reflection cracks. For the same sections, the thickness calculated using different methods is different . In design should be analyze and compare all kinds of results, determine the final layer thickness incorporating with the practical experience.3,Before overlay asphalt layer on the old cement concrete pavement, it needed to investigate and assess the condition of old road scientifically, to has a comprehensive understanding of the using state and defects of old cement concrete pavement, and to provide information on the treat ment of old road damage. The quality of the structure functional recovery of the old road is essential to the overlay design. Which pavement damage and the structure carrying capacity of the old pavement is the focus of evaluation of the old road.4,Before overlay asphalt layer, we should attach importance to the disease treatment of the old cement concrete slab, combined with a variety of the old road damage appeared and analyze its causes, take corresponding measures to improve the intensity of the old pavement slab. This project old road pavement mainly has the damage of corner cracks, horizontal cracks,slab and slab staggering, analysis of disease was mainly attributable to the role of serious overloading of vehicles, high temperature, as well as the role of the surface caused by water infiltration. According to the form of disease, put forward the corresponding measures mainly to seam, cracks, fracture ,slab damage and slab staggering .5,On the basis of taking full account of the climate of the project, traffic characteristics, as well as the service performance and durability of overlayer in the design period,bring forward the renovation plan of asphalt overlayer. Overlayer is 4cm thick layer of SMA modified asphalt concrete, and using glass cloth for the link layer.6,In accordance with the overlayer plan and asphalt concrete mix design, through the overlay construction practice of Expressway to Jingyue section of Changda highway, summarize the construction technology, construction attentions and quality control of the mixture mixing, paving, roller etc. of the modified asphalt mixture of SMA-16 asphalt overlayer technically.7,As long as strengthen and attend the quality control in the design, construction and management , overlay asphalt mixture on the old cement concrete pavement is not only technically feasible, but also can increase the traffic quality of the road, improve traffic conditions, extend the service life of the road, save money and shorten the construction period of the old road renovation,has better economic and social benefits.