Evaluation of Field Performance of Warm-mix Asphalt Pavements in India

Abstract

The United States and European countries are increasingly using “warm-mix” technologies that allow a significant reduction in the production and placement temperatures of asphalt mixes. Such mixes are also gaining popularity in other parts of the world in countries like China, Brazil and India. Though warm-mix asphalt (WMA) is a relatively new technology, contractors and Government agencies in the West have been quick to recognize the environmental and performance benefits of warm- mixes due to extensive research. This research has also allowed several Government agencies, such as the Federal Highway Administration (FHWA), to promote WMA as an important technological innovation for the industry. Many agencies have developed specifications for the use of WMA, which allows more contractors to use WMA. In India, Central Road Research Institute (CRRI) has carried out initial research on the effects of WMA on Indian mixes. Certain warm-mix technologies have since been used to pave major national and state highways as well. However, lack of awareness and skepticism of field performance is shying more contractors and agencies from using WMA extensively as in the West.This paper attempts to evaluate the field performance of two pavements constructed using an IRC accredited surfactant based chemical warm-mix technology. The two pavements evaluated in this study were produced and placed at a significantly lower temperature relative to the control hot-mix sections. Both the pavements were evaluated after considerable exposure to weather elements and traffic. Methods like Benkelman beam deflection, bump integrator value, and Marshall stability, resilient modulus and static creep test on field cores were used to evaluate the performance of the WMA sections in comparison to the control hot-mix sections. The results of the study indicate that in spite of the several monsoons and heavy traffic both pavements were exposed to, the performance of the warm-mix sections was equal or better compared to the control hot-mix sections. Due to the improved densities achieved at the site, and due to the reduced oxidation of the bitumen as a result of the lower production and placement temperatures, the performance of the warm-mix seemed to be improved in terms of permanent deformation and resilient modulus.