Optimal schedule adjustments for supplying ready mixed concrete following incidents

In this study, the authors develop a systematic network flow model designed to help RMC carriers effectively adjust schedules following RMC mixer breakdowns. A time-space network technique is employed to formulate the production of the RMC and truck fleet flows in the dimensions of time and space. A solution algorithm, incorporating a problem decomposition technique and the use of a mathematical programming solver, is developed to efficiently solve the problem. Finally, the model and solution method are evaluated by performing a case study. The test results show that, with the application of the model and the solution algorithm, mixer breakdowns do not lead to much deterioration in the system operating performance. In addition, the system operating cost is significantly improved (by 10.75%) compared to that obtained using the manual approach. As a result, the model and the solution algorithm could be useful for actual operations. (C) 2011 Elsevier B.V. All rights reserved.