The spring of 1997 wasn't a pleasant time for many concrete producers and contractors in Minnesota, where the wet November and harsh winter of 1996-1997 produced an incredibly high number of callbacks related to concrete scaling.The Bauerly Companies, which operate 20 ready-mixed plants, had customers reporting many more problems that were not common to any one area, supplier, product or contractor. Even contractors who used recommended practices and regularly had their workers attend training classes were experiencing scaling problems. As a result, homebuilders and developers were considering alternatives to concrete for driveways and patios.Bauerly managers took a proactive approach to the scaling problem. That, according to Bauerly Quality Control Manager Tom Rogers, "involved gathering more information and partnering with both our suppliers and customers."The first step was a meeting attended by suppliers of cement, admixtures and curing and sealing products.The next step was gathering samples of scaled concrete from all four of the Bauerly Companies' sales regions, grouping similar symptoms or defects, and then submitting samples to American Engineering and Testing for petrographic examinations.Bauerley then invited contractors and owners to partnering meetings. A majority of contractors from every region believed cement was changing and causing the problems.Within 30 days of the first round of meetings, AET hosted a problem-solving meeting. Attendees decided a concerted effort in the following four areas had the highest likelihood of improving exterior flatwork quality:
- Developing standardized concrete mix proportions, finishing methods and curing procedures.
Volunteers worked to develop the best mix proportions and install and finish sample slabs.The study underscored the importance of a low water-cement ratio. The study also revealed an unexpected result. Panels given a steel trowel finish performed as well or better than concrete finished with a wood float.Partnering is a viable approach to solving performance problems that involve all members of the construction team.Keywords: scaling, Bauerly, air, fishbone, Pareto