Improved Fatigue Performance and Cost-Effectiveness of Natural Rubber Latex–Modified Cement-Stabilized Pavement Base at Raised Temperatures

Abstract

The increased temperature at the early state of curing affects the fatigue properties of pavement base materials. The fatigue properties of stabilized pavement bases and subbases govern the performance and service life of pavement structures. This research study utilized natural rubber latex (NRL) to enhance the tensile fatigue properties of cement-stabilized base materials at various temperatures. The effects of influence factors such as cement content (3%, 5%, and 7%), NRL replacement ratio (0%, 10%, 15%, 20%, 25%, and 30%), and temperature (25°C, 40°C, and 60°C) on indirect tensile strength (ITS), indirect tensile resilient modulus (IT Mr), and indirect tensile fatigue life (ITFL) were studied in this research. NRL replacement was found to improve the UCS, ITS, IT Mr, and ITFL of cement (C)-stabilized soil up to the highest values at the optimum NRL replacement ratios, which were 20%, 15%, and 10% for cement contents of 3%, 5%, and 7%, respectively. The cement-NRL (C-NRL)-stabilized samples were found to have superior ITS, IT Mr, and ITFL values compared with C-stabilized samples for the same cement content but had the same rate of reduction in ITS due to the raised temperature. For the NRL replacement ratio on the dry side of optimum, the C-NRL-stabilized samples had lower rate of IT Mr reduction than the C-stabilized samples, although they had the same ITS due to the higher toughness. Therefore, the rate of ITFL reduction of C-NRL-stabilized samples was lower than that of the C-stabilized samples. It was proven in this research that the NRL replacement could reduce the thickness (superior IT Mr) of a cement-NRL-stabilized base course for a given traffic volume and service life, and therefore the construction (material and operation) cost by 17.26% benchmarked to a C-stabilized base course. Finally, the cost-effective design method for C-NRL-stabilized bases course was proposed, which will promote the use of NRL as an alternative green additive instead of synthetic polymer.