Process Control in Practice

Our approach to process control is discussed for portland cement as this is the only phase of construction that we encounter. Our process-control system has been in existence since we first started to produce transit mix concrete in the late 1930s. Management took the position from the start that it would provide a quality product-to the point of overdesigning mixes to allow for some error in placement, handling, and testing. This was done and still is being done, to a lesser degree now, at the expense of the company. Changes in the concept of quality assurance introduced by the West Virginia Department of Highways in the mid-1960s, which were accepted by us in the early 1970s, have helped us to achieve and document goals of consistency in our manufactured product. Consistency was achieved by training technicians, setting up our own certified laboratory, maintaining complete control of our aggregates, testing cement from our suppliers, and, probably most important, switching from transit mix to an automated central mix plant. The sharing and use of test data collected by electronic data processing have been invaluable to us in our daily operating procedures. The raising of the iron curtain of communications from the owner to the contractor to us, the supplier, also contributed greatly.