Preliminary constituent proportioning for central plant hotmix asphalt recycling

Different methods for preliminary constituent proportioning of the recycled mix are proposed in various guidelines/studies for central plant hotmix asphalt recycling. These methods are sequential in nature, and the process requires at least one of the parameters (for example, quantity of reclaimed material or viscosity of virgin asphalt binder) as fixed. An attempt has been made in the present work to develop a generalized formulation for the mix proportioning which does not require any such prefixing; however, the formulation is flexible enough to take care of such a constraint, if imposed. The proposed formulation serves certain overall objectives, like minimization of material cost, maximization of usage of reclaimed material etc., with the help of a linear programming tool. The suggested approach handles the proportioning problem as a whole, and is therefore not dependent on the sequence of mix proportion calculations.