Just-in-Time Concrete Delivery: Mapping Alternatives for Vertical Supply Chain Integration

This paper explains concepts underlying a just-in-time production system. Just-in-time production systems as implemented by Toyota are pull systems in which ‘kanban’ convey the need to replenish the right inventory at the right time and in the right amount. In this paper, symbols from manufacturing are introduced to map resource flows in order to help distinguish traditionalfrom lean production processes. These symbols are then applied to construction. Ready-mix concrete provides a prototypical example of a just-in-time construction process. Ready-mix concrete is a perishable commodity, batched to specifications upon customer demand. This makes just-in-time delivery necessary. Based on data from industry case studies, alternative forms of vertical supply chain integration were investigated. The most common one is where the batch plant also delivers the mix to the contractor’s project site. An alternative is for the contractor to haul the mix from the batch plant to the project site with their own revolving-drum trucks. One alternative is favored over the other depending on the amount of control the contractor wants in terms of on-time site delivery of concrete and the variability in the contractor’s demand for concrete project after project. Insights can be gained from these two examples on how the construction industry has adopted a just-in-time production system for at least one part of the concrete supply chain. The examples provided will help the reader think through issues pertaining to the need for having information, materials, and time buffers at strategic locations in construction processes.