Issue link: https://mastery.commandalkon.com/i/1127584
The Challenge Arizona Metro Mix was award a job where the concrete, with tight requirements for air content, was required to be delivered up the side of a mountain. Bob Matthews, Operations Manager for Arizona Metro Mix, originates from Michigan where air entrainment is used all the time…however, they don't use much in Arizona and historically the company had struggled to contain entrained air variation to no more than one and one-half percent (± 1.5%) from load to load. Arizona Metro Mix doesn't have a separate QC department. Arizona Metro Mix had used probes before which were, in their opinion, only slightly better than nothing. Sand coming in from the quarry varies from 0% to 4% from load to load, with an upper range of 12%. Using the probes Arizona Metro Mix has historically used, if the incoming sand varied by more than 2%, they would have to recalibrate. Since the material was constantly coming in Arizona Metro Mix was always "chasing" the moisture and slumps were "… all over the place." Recalibration with the old probes was frequently required three times per day. The Solution Concern about being thrown off jobs for inconsistencies was never far out of mind. Before the mountain job started the old probe quit and the company was forced to act. Arizona Metro Mix chose to add the Precision Water System on their worst plant where the SE of the fine aggregate can vary from 68 to 92 over a period of a few days. Arizona Metro Mix is a four plant, 42 truck contractor/producer providing concrete to the Greater Phoenix Metro Area. Arizona Metro Mix PRECISION WATER SYSTEM LOCATION Phoenix INDUSTRY Producer RESULTS Zero Rejected Loads iStock Image