The Quest for Performance-Related Specifications for Hydraulic Cement Concrete

About the report:

This paper reviews some of the problems associated with quality assurance for hydraulic cement concrete and the difficulties of relating the results of quality control and acceptance testing to the performance of the concrete facility. The importance of good control procedures and inspection of concrete placement by persons knowledgeable in concrete technology is stressed. Also, it is concluded that acceptance procedures based on statistical probabilities are a first step towards attaining the ultimate goal of specification requirements optimally related to performance. The major problem in this area is identified as one of obtaining sufficient test data to establish an acceptable degree of confidence that the quality of the concrete is as indicated by probability theory. Because of the time and expense of most acceptance tests, particularly strength tests, decisions must be based on limited data. The report summarizes the specifications of other agencies utilizing statistical probabilities and the recommendations of the American Concrete Institute concerning acceptable strengths. Finally, an evaluation is made of the technique most applicable to the Virginia Department of Highways and Transportation, and specific recommendations are made for changes in the Department's specifications. It is recommended that the revised specification be evaluated by simulated applications to several construction projects.

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