Highway Research Record

VI. RESEARCH WORK DONE IN ACADEMIC INSTITUTIONS RELATED TO THESIS WORK
B. PAVEMENT ENGINEERING AND PAVING MATERIALS
Mix Design for Hot Mix Recycling of Bituminous Mixtures

Date of Start:May 2004
Indian Institute of Technology, Kanpur (R, I)

Scope and Objective
(i) Development of a suitable formulation for constituent proportioning of a recycled mix.
(ii) Evaluation of the mixes prepared through performance based tests.

Methodology
The constituent proportioning is done using linear programming as optimization tool. The constraints have been formulated in such a way that the mixture viscosity of the recycled mix matches with the specified viscosity and the total bitumen content satisfies the optimum bitumen content of the recycled mix. The objective function is chosen as maximization of reclaimed asphalt pavement (RAP) or minimization of cost. Fatigue and static creep tests are performed on the recycled mixes and compared with the fresh mix.

Findings and Conclusions

A suitable formulation using optimization as a tool has been developed which provides a rational basis of choosing the RAP quantity. Performances of recycled mixes are comparable to that of mixes prepared using fresh aggregates.