DESIGN AND EVALUATION OF COLD IN-PLACE RECYCLED PAVEMENTS

Cold In-Place Recycling appears to be a cost effective rehabilitation method for some flexible pavements. However, difficulties exist in constructing projects due to non-standard mixture design and analysis techniques. As a part of the cold mix recycling process, the old and aged mix is milled out and is mixed with a virgin aggregate and additional asphaltic rejuvenator to make the recycled mix meet the standard specifications. The recycling agents or rejuvenators for cold mixes are emulsified asphalts, either cationic (CMS) or anionic with high-float characteristics (HFRA). The mix design for cold mixes containing emulsified asphalts is significantly different from the conventional hot asphalt mixes. Currently, there is no standard procedure for design of cold emulsified asphalt recycled mixes. The objectives of this study were to: (1) Develop a methodology for cold mix design using CMS and HFRA emulsions as recycling agents; (2) Evaluate and characterize these cold mixes in the laboratory and compare the likely performance with the conventional hot asphalt mixes; (3) Through laboratory characterizations, evaluate the structural contribution of cold recycled mixes in pavements; and (4) Develop guidelines for design and construction of cold mix binder layers.