Mechanistic evaluation of hedmanite and lime modified asphalt concrete mixtures

The investigation was undertaken to evaluate the effectiveness of using hedmanite (rockwool natural fibers) as filter in improving the performance of asphalt concrete pavements, and to compare hedmanite with lime (as filler) modified mixes and the conventional asphalt mix containing crushed stone filler. In this study, optimum asphalt content was obtained by Marshall method and was used in all the modified mixes. The engineering properties, including resilient modulus, stability loss, split tensile strength, fatigue and permanent deformation, were determined. Results indicated that certain percentages of both hedmanite and lime are effective in improving the resilient modulus, while the Marshall stability loss and tensile strength loss were higher in hedmanite mixes than in lime mixes. Lime modified mixes showed better resistance to fatigue and rutting than hedmanite modified mixes. Results indicated that better quality asphalt concrete mixes can be prepared using lime rather than hedmanite as a filler.