Impact analysis of Carboxyl Latex on the performance of semi-flexible pavement using warm-mix technology

In order to improve the performance of semi-flexible pavement material, Carboxyl Latex is tried to be added into cement mortar as additives, in this study. Then, the degree of cement mortar performance improvement is evaluated, and the appropriate proportion of Carboxyl Latex added is determined. The improved cement mortar performance evaluation indicators used include fluidity, compressive strength, flexural strength, and drying shrinkage. Then the influence of the Carboxyl Latex on semi-flexible pavement material performance (high-temperature rutting, low temperature crack, water damage and fatigue) with warm mixed open-graded asphalt mixture matrix of varied air void contents is tested. Study results show that the addition of Carboxyl Latex reduces the rutting depth of pavement material by 30% or more, increases the dynamic stability by more than 40% and the strain energy density to 1.6 times, and the freeze-thaw splitting tensile strength is also increase by over 93%. Furthermore, the value of K increases by more than 6%, and the n value decreases by 12% or more, in where, the two parameters, K and n, represent the fatigue resistance of semi-flexible pavement material that can be obtained from the regression equation of loading numbers vs. stress levels of fatigue test. The larger K value or the smaller n, the better the fatigue resistance. Overall, after adding the Carboxyl Latex into cement mortar, the high-temperature rutting resistance, low-temperature crack resistance, water damage resistance, and fatigue resistance of semi-flexible pavement materials have been significantly enhanced.