Title: The Ready Mixed Concrete Producers’ View of In Situ/NDT Testing

Author(s): Ken Newman

Publication: Symposium Paper

Volume: 82

Issue:

Appears on pages(s): 479-500

Keywords: compressive strength; nondestructive tests; quality control; ready-mixed concrete; specifications.

DOI: 10.14359/6569

Date: 9/1/1984

Abstract:
This paper examines the influence of workmanship on the properties of concrete and the difference between the results obtained from standard specimen and in-situ tests. Few reinforced concrete engineers appear to understand the relevance and meaning of the results of in-situ/NDT tests. These methods measure concrete properties in the actual structure (i.e. "real-Crete") which engineers should be interested in, whereas they still place undue emphasis on the results from standard tests (i.e. "lab-Crete"). The respective responsibilities of the ready mixed concrete producer and contractor are defined. Recommendations are made for improving the reliability of compressive testing by means of standards for testing machines and their use, for differentiating between "lab-Crete" and "real-Crete" by providing guidance on the assessment of concrete strength in existing structures, and for specifying the required concrete properties in terms of the "lab-Crete" compressive strength.