Cold Asphalt Mixes for Indian Highways Environment Friendly Technology
Prof. Prithvi Singh Kandhal, Associate Director Emeritus, National Center for Asphalt Technology, Auburn University, Alabama USA
Introduction
Cold asphalt mix is produced by mixing unheated mineral aggregate with either emulsified bitumen or foamed bitumen. Unlike hot mix asphalt (HMA), cold asphalt mix does not require any heating of aggregate which makes it economical and relatively pollution-free (no objectionable fumes or odours). Production of cold asphalt mix does not require high investment in equipment, which makes it economical. It is also suitable for use in remote areas. Cold asphalt mixes can be used both for initial construction (100% virgin mixes) and for recycling of asphalt pavements.Cold asphalt mixes do have some limitations. These mixes should not be used when ambient temperatures under 10°C are expected during construction. Cold asphalt mixes are typically suitable for light to medium trafficked roads when used in base and surface courses. Since their structural strength is relatively lower than that of HMA, the pavement structure should be designed properly.