In the last two years, there's been a renewed industry focus on improving the quality of ready-mixed concrete. In response, we interviewed 47 top quality control managers around the country. We asked these managers at major companies in 19 states about their biggest challenges in developing mix designs and in their field operations.
We found a few problems showed up over and over again. In fact, just eight issues accounted for most the managers' time and gray hair. Some of these have been major trouble areas for decades, but a few have cropped up only recently. And many of them are connected to each other. Here are the issues they brought up most.
Those industry leaders who are advocating the Prescription to Performance, or P2P, initiative are onto something. More QC managers named poor specifications as a major problem more often than any other issue.
One complaint was often the specifications within the bid document or scope of operations were inconsistent with each other. Many managers shared a story like the one from Shawn Baker of S&W Ready Mix Concrete in Clinton, N.C. “Sometimes the engineers will spec a slump or water/cement ratio that is impractical for the specified strength,” he says.
Lack of knowledge of local conditions creates problems, Baker adds. “Often, the engineers of record are from another state,” he says. “They specify materials or combinations of materials that aren't available to us.”
But these managers see a greater problem with spec inconsistency. The poorly written specifications would produce a product that isn't as good or as inexpensive as it could be.
“Most customers know very little about new materials and admixtures,” says Jim Kleffel of Berks Products in Reading, Pa. “They spec what they know, when we could make a better mix if they gave us more flexibility. For example, some customers still only accept straight portland cement mixes. If they'd let us use other cementitious materials, we could save them money and improve workability, but they don't want to hear it.”