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Powered by the simulation and optimization engines resulting from recent research, a computer system named HKCONSIM is ready to provide concrete plant managers with decision support in making the best operation strategy for delivering concrete to multiple site clients. This paper demonstrates case studies of HKCONSIM applications in practical settings with emphasis on addressing two questions: (1) "Can HKCONSIM capture the complexities of the real world?" and (2) "How to take advantage of HKCONSIM to attain customer satisfaction and cost effectiveness?" A case study describing one-day operations of the batch plant is used to illustrate the decision support functions HKCONSIM can provide. The case study consists of four parts: (1) input data preparation, (2) the definitions of relevant measures of the system performance, (3) simulation model validation by comparing the simulation outputs against the actual records, and (4) further optimization analysis under three "what-if" scenarios postulated with practical implications. In conclusion, the batch plant operators can draw on HKCONSIM to augment their experiences, corroborate their intuitions, and create new intelligence in coping challenges in day-by-day operations planning. INTRODUCTIONThe benefits of ready mixed concrete (RMC) in light of attaining consistent quality standards, being environmentallyfriendly, and demanding less site space have accounted for its ubiquitous application in infrastructure and residential building projects. The scheduling of RMC production and delivery is essentially a problem of materials logistics planning, which is "a decision process for strategically managing the procurement, movement and storage of raw materials, finished product inventory and the related information flows throughout the organization and its marketing channels in such a way that the current and future profitability is maximized by cost-effective fulfillment of orders" (Christopher 1992). In Hong Kong, a RMC plant generally requires a three-day advance notice for ordering concrete delivery service, with the order confirmed one day before the actual pour date. Raw material stocks at a plant are replenished on a daily basis in preparation for the next-day's production which is pulled by site orders placed by multiple clients. A RMC plant transforms raw materials into concrete in its production facility and is committed to delivering concrete to different construction sites by truckmixers so as to match the onsite concreting progresses. The elapsed duration from the introduction of water to the final placement of the concrete is of particular importance to the quality control of ready mixed concrete. For example, ASTM C94 (ASTM 2000) allows a maximum of 1.5 hours (90 minutes), or before the drum has made 300 revolutions, whichever comes first. The Hong Kong common practice is to unload concrete into the forms on site within 1 hr 45 min of first mixing as a maximum time limit. Due to the perishable nature of concrete, the batching and delivery operation of the RMC in...