Title: The Importance of Seeing the Forest Instead of the Trees

Author(s): Ken Day

Publication: Concrete International

Volume: 32

Issue: 3

Appears on pages(s): 60-61

Keywords: strength test, quality assurance, required strength, CUSUM

DOI:

Date: 3/1/2010

Abstract:
The author recommends that the industry must avoid considering a single test result to be an invariably accurate judgement that a truck of concrete is or is not acceptable. Any single strength test result alone can’t be assumed to be necessarily exactly correct, and should therefore not lead to hasty action confined to the truckload of concrete in question. Unit weight, slump, concrete temperature, details of concrete production, and test cylinder collection and treatment should be examined to help establish whether a low test result is genuine. Test results on similar and concurrent concrete deliveries should also be examined. A quality assurance program should include entering test results in a multivariable graphical analysis system to detect trends and influences.