ABSTRACT
Cold mix asphalt mixture has a low strength and poor water stability, hence to solve this challenge, a cold mix asphaltic liquid was prepared in this study based on microscopic properties. LB-10 gradation was adopted and basalt fiber was selected as a reinforcing agent. The optimum asphaltaggregate ratio was determined by the Marshall test, and mix proportion was also designed. The laboratory tests were used to systematically evaluate road performance of the cold mix asphalt mixture. From the test results, it was shown that the initial strength, molding strength, immersion Marshall strength, residual stability, freeze-thaw splitting ratio, residual rate and dynamic stability of self-made cold mix asphalt mixture were 2.42 kN, 4.87 kN, 6.79 kN, 92.8%, 82.05%, 99.5% and 632 times/mm respectively. The initial strength, molding strength and residual stability of mixture became 90.9%, 88.7%, and 96.2%, respectively of their former values after one-month storage, showing good workability. By analyzing its research data and comparing with its existing products, the developed cold mix asphalt mixture can not only meet the requirements for road performances of the cold mix asphalt mixture in terms of strength, workability and high temperature stability, but greatly improves the water stability, storage stability and cohesive performance of the mixture.
ABSTRACT
High-performance cold mix asphalt was prepared based on suitable cold mix asphaltic liquid. First, the contents of raw materials were estimated. The optimum composition of asphaltic liquid was determined by the orthogonal experimental design method. The properties of evaporated residue, adhesiveness, and construction workability were determined. At the same time, the microscopic characteristics of cold mix asphaltic liquid were analyzed by scanning electron microscopy (SEM). The results indicated that Brookfield viscosity was greatly influenced by diluent content at 60 °C. Brookfield viscosity was decreased with the increase of diluent content. Brookfield viscosity was hardly influenced by contents of the additive and styreneic block copolymers (SBS) at 60 °C. Samples 2, 3, 5 and 6 met the requirement of viscosity. The penetration degree of the evaporated residue in asphaltic liquid met the requirement for roads. The Chinese Standard JTG F40-2004 was used to measure the ductility of asphaltic liquids at 5 and 15 °C. The softening points exceeded 50 °C, indicating the excellent high-temperature performance of cold mix asphaltic liquid. The adhesiveness between asphaltic liquid and aggregates was graded at Level 5 (Chinese Standard T0616-1993). The mixture containing samples 5 and 6 was slightly white in color, the fine aggregate was exposed completely. Changing the temperature of the mixture from 90 °C (testing temperature) to 70 °C (mixing temperature), the adhesiveness between aggregate and asphalt was reduced. The fine aggregates were not exposed in the mixture containing samples 2 and 3, and the corresponding mixing ratios can be applied for the production of cold mix asphaltic liquid. Modifiers and additives in cold mix asphaltic liquid were uniformly dispersed. At the same time, it demonstrated that the diluent showed a certain influence on the morphology of residue of cold mix asphaltic liquid, so that a number of folds and holes existed on the surface of the residue.
