![]() ![]() The cement not only could accelerate the emulsion breaking, but can also increase the stiffness of CRME. The main effect of cement on the performance is controlled by the reactions between cement and asphalt emulsion. In contrast, CRME might be classified as cement-treated material when the content of cement is greater. CRME might be classified as asphalt-stabilized material when the content of cement is lower. ![]() Generally, the content of cement is from 1 wt.% to 3 wt.% in CRME. ![]() Compared to other additives the cement has better effects. The modified asphalt emulsion could also be considered as another means. However, additives are not the only way to improve the performance of CRME. Therefore, many additives, such as fly ash, cement, and limestone powder, were used to enhance the performance of CRME. However, with the earlier studies and experiences of cold recycled mixes using asphalt emulsion (CRME), some problems appeared, such as excessive deformation, low initial strength, and weak adhesiveness. Since the 1970s, asphalt emulsion has been used as the most common recycling agent in cold recycled mixes because it is liquid at room temperature and helps the dispersion of asphalt emulsion in the mix. The cold recycling technology has been largely used as surface and base course in a pavement system, which can make full use of plenty of old asphalt materials and reduce environmental pollution from old asphalt materials and greenhouse gases. One of the promising ways to recycle old asphalt materials is cold recycling technology. Highway agencies have attempted to reuse old asphalt materials to solve these critical issues. In addition, the shortage of suitable property aggregates severely limits the construction and maintenance in the pavement industry, which causes resource and environmental problems. These materials occupy a mass of land and pollute the environment. ![]() The study will be significant to better know the effects of cement and promote the development of CRME.Īccording to recent data, about 60 million tons of old asphalt materials are produced in China every year. The results of microstructure and energy spectrum analysis show that the composite structure is formed by hydration products and asphalt emulsion. Cold recycled mixes had better low-temperature cracking resistance when the contents of cement were in the range from 1% to 2%. However, it gradually decreased when the content of cement is increased from 1.5% to 4%. The low-temperature crack resistance ability gradually increased when the content of cement is increased from 0% to 1.5%. Results show that the high-temperature stability and moisture susceptibility of CRME increased with the contents of cement increasing. The microstructure and chemical composition of the fracture surface of CRME with different contents of cement were analyzed in this paper as well. In order to determine the optimum range of cement contents, the complex interaction between cement and asphalt emulsion and the effects of cement on performance of CRME were investigated with different contents of cement. Cold recycled mixes using asphalt emulsion (CRME) is an economical and environmentally-friendly technology for asphalt pavement maintenance and rehabilitation. ![]()
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