目前國內外營建工程所需的混凝土材料，大部份多來自預拌混凝土廠。但由於預拌混凝土產業的特性；例如：1. 工地對混凝土的需求不定時；2. 混凝土無法事先拌合存放；3. 工地對混凝土派送的需求集中於特定時段；4. 預拌廠的服務區域有限；使得預拌廠在派送混凝土作業上一直存在著瓶頸。而目前大部分的預拌廠，在混凝土的配送作業上，大多取決於派送員之主觀經驗，缺乏一套系統化的管理方式。因此常常造成大多數的預拌車排隊在某一工地等待灌漿，而其他有需求的工地苦等預拌車的到來，不僅影響工地的作業也減低預拌廠的生產力。此外隨著供應鏈體系建立的需求，不同混凝土廠已有趨向整合的現象。因此混凝土的配送作業逐漸受到重視，已不能單靠主觀經驗判斷，而須建立一以派遣中心為基礎的系統化預拌混凝土派車模式。
本研究針對以上問題，建立一以派遣中心為基礎之系統化多預拌廠供應多工地預拌混凝土車派車模式，並利用基因演算法與電腦模擬的方式，探討如何安排各預拌廠到各不同工地的派車順序，使得預拌廠能在合理時間內找出符合所有限制條件的最適派車排程，即工地待料時間與預拌車在工地排隊等待卸料時間為最短。並利用Visual Basic撰寫之電腦程式，製作一套以混凝土派遣中心為主的輔助決策系統。研究結果顯示，此一派車模式不僅能在合理時間內提供最佳的派車排程，多目標的解答亦提供具有彈性的決策空間。

Concrete is the one of the most widely used material in the construction industry. Nowadays, concrete is usually produced and delivered by the RMC (Ready Mixed Concrete) batch plant because of its timely and sufficient supply. Therefore, effectively and efficiently delivering RMC to construction sites is an important issue to the RMC batch plants manager. The RMC batch plants manager has to consider both timeliness and flexibility to develop an efficient schedule of dispatching RMC trucks, which balances the operations at the construction sites and the batch plants.
The requests of RMC deliveries from different construction sites usually swamp into the batch plant at certain working hours. As a result, the batch plants manager has to quickly decide a dispatching schedule that can satisfy the needs from different construction sites. The existing dispatching schedule mainly depends on the experiences and preferences of the dispatcher. For example, the RMC plant manager may dispatch as many RMC trucks as possible to the busiest construction site. However, such an approach might result in the RMC trucks line up at the busiest job site while keeping other construction sites waiting for the arrivals of RMC trucks. A systematic approach to such a problem has seldom been taken due to the complexity and uncertainty involved within the dispatching process. In addition, as the needs of developing the Supply Chain in the RMC business grow, the development of a dispatching center that integrates different RMC batch plants becomes necessary and a must. Dispatching center can take orders from different construction sites and find the best schedule that determines the sequence of dispatching RMC trucks from which batch plant to which construction sites. Therefore, there is a need to develop a systematic approach that optimizes the schedule of dispatching RMC trucks according to the development of a dispatching center.
This research builds a model of dispatching RMC trucks based on the operation of the dispatching center. Genetic Algorithms (GA) and simulation technique are used to find the best dispatching schedule which minimizes the total waiting duration of RMC trucks at construction sites and the total idle time of construction sites for arrivals of RMC trucks. In addition, a user-friendly computer program is built to help the batch plant manager easy the dispatching process. Results show that this new systematic model along with the implemented computer program can quickly find efficient solutions of dispatching RMC trucks. In addition, the multiple-objective approach provides decision maker a flexible answer.

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