Proactive And Reactive Scheduling For Production And Delivery Of Ready Mixed Concrete With Multi-mixer

Ready mixed concrete(RMC)is a kind of construction materials which is now widely used in the world.RMC is usually supplied by off-site concrete enterprises which collect orders from construction sites,then arrange production and delivery concrete to the corresponding construction sites.Managers of RMC enterprises mostly schedule concrete production and dispatching based on the artificial experience,which is not an efficient approach.In literature,most research focused on the problems with single mixer,but multiple mixers are often employed in reality.So the integrated scheduling problem of mixers,trucks and pumps in RMC plant with multi-mixer is studied in this paper.A time-space network flow model which combines RMC production and vehicles dispatching is formulated in this paper.Then a proactive heuristic scheduling algorithm which contains eight sets of conjoint priority rules(including production sequence rule,vehicle scheduling rule,mixer scheduling rule)is developed.To evaluate the advantages and disadvantages of different sets of conjoint priority rules,some evaluation functions on the costs and travelling time are proposed.Computational experiments are conducted on real cases collected from a RMC company which are classified into four types based on the quantity of orders from construction sites and the discrete degree of construction sites.The advantages and disadvantages of adopting various conjoint rules in different types of cases are found.Based on the proactive heuristic scheduling algorithm,a reactive scheduling algorithm is proposed.The reactive algorithm can conduct partial adjustments on the baseline schedule when a disruption happens such as new coming orders,which aims at reducing the affection of disruptions.The experimental results show that the local adjust reactive algorithm can reduce the adjustments of the baseline schedule effectively compared with completely rescheduling algorithm.One contribution of this study to the literature is that a problem of operation process in a RMC plant which includes multiple mixers with different production rates and costs is presented.Practical cases are classified into four types based on the quantity of orders from construction sites and the discrete degree of construction sites.This can help RMC enterprises choose more suitable conjoint rules in different cases.Then the reactive scheduling algorithm is studied to help RMC enterprises schedule production and delivery in order when disruptions happen.Thus this paper can provide RMC enterprises a scientific and effective guidance in practical operations,then improve operational efficiency and reduce business operating costs.