| Hot in-place recycling is a new type of highway maintenance technology, whose technology is relatively mature in the developed countries and which has been popularized and applied in our country recently. In contrast to traditional milling, hot in-place recycling technology has many advantages on the rutting damage repair. Currently, however, hot in-place recycling technology has emerged renewable pavement rutting. Aimed at rutting problems for hot in-place recycling, the paper speculates analysis of its causes based on analysis we carried out indoors Marshall test and rutting test and makes appropriate recommendations to effectively improve the rutting for hot in-place recycling.In this paper, it is infered that the reason appearing rut is that the performance of RAP material and content is unreasonable, construction of heat insulation is not controllable.Firstly, this paper analyze and research the RAP. Centrifuge method is employed to extract asphalt and aggregate from the RAP. Then the asphalt is recycled by Abson method. The aggregate stripped and Sifted can’t meet the specification’s needs and need to have gradation adjustment. Verified By recycled asphalt performance and analyze the degree of aging and determined to take the old asphalt recycling agent and adding new asphalt regeneration mode. Ultimately it is determined to use A regeneration catalyst and the amount of regeneration agent whiche is 6%(proportion of old asphalt) is better feature pointsFollowed by designing of hot in-place recycling target bituminous mixture, determine the type of renewable mix AC-13 and established three different RAP content(75%, 85%, 95%) and three different test temperature(130,145,160℃); determining RAP at the dosage of 75%, 85%, 95%, The optimum proportion of regeneration mixture are 5.3%, 5.1% and 5.3% respectively. Followed by the different proportions of Marshall test, calibration density, saturation, porosity, VMA, Marshall stability and flow value of the nine cases are standardized. It is found that 95% RAP content discovery and 160℃ correspond mix is the best and old material is inversely proportional to the density of ash and recycled materials, saturation, stability, proportional to the current value, and renewable materials porosity and VMA. Temperatures will increase the density, saturation, and value increases flow stability, porosity and VMA decreases.It is drawed the conclusion below in the rutting test. Increasing old material content will bring dynamic stability and improving rutting resistance, however the difference rutting resistance greater volatility, which is expected by the fluctuations in the difference RAP decisions. When experiments molding temperature increase, recycled mixture rutting performance has greatly improved. RAP content leads to a lower increase immersion Marshall and freeze-thaw splitting indicators show excessive water content or low temperature stability performance may decrease. In addition, a brief warm mix technology demonstration test results show that the amount of warm mix agent is added to reduce the test temperature in the premise of ensuring the quality of construction.This paper shows that it is important that field test mixing temperature for resistance rutting after forming,so paying attention mixing warm in construction. Selecting the appropriate dosage RAP has multiple effects on the hot in-place recycling. So we should comprehensively consider and carefully choose, not to blindly pursue high dosage. |
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