Do producers of ready mixed concrete ever guarantee the strength of their product?
It isn't by any means a common practice. One prominent firm in the industry, Material Service Corporation of Chicago, recently announced a strength guarantee as the cornerstone of its approach to marketing structural concrete. The plan is believed to be the first of its kind offered in the Chicago Metropolitan Area. The company invites architects, engineers and contractors to furnish it with data about how concrete is to be used; it will then design a mix of the proportions of sand, gravel, cement and water (and the gradations of the sand and gravel) that it recommends in order to achieve the desired results; and finally, it guarantees that the concrete will perform as required.
Editor's note: It has been brought to our attention that Pacific Cement and Aggregates, a division of Lone Star Cement Corporation, of San Francisco, California, has successfully produced guaranteed strength concrete since 1940. They are currently using statistical control methods utilizing their computer and a full "quarry to forms" quality control system.