Title:
How Good Is Good Enough?
Author(s):
Edward A. Abdun-Nur
Publication:
Journal Proceedings
Volume:
59
Issue:
1
Appears on pages(s):
31-46
Keywords:
none
DOI:
10.14359/7914
Date:
1/1/1962
Abstract:
How good should concrete be to serve its intended How-good should concrete be to serve its intended purpose? To answer this, several typical specifications are evaluated To answer this, several typical specifications are evaluated statistically relating results from an average protect ated statistically relating results from an average protect to physical iob conditions. to physical job conditions. Concludes that minimum strength specifications are un- Concludes that minimum strength specifications are un-realistic, not generally met in practice, and tend to obscure realistic, not generally met in practice, and tend to obscure the real safety factor. However, specifications based on the real safety factor. However, specifications based on average strength geared to coefficient of variation, per- average strength geared to coefficient of variation, permitting a reasonable number of low strength values, are mitting a reasonable number of low strength values, are more realistic, lower costs, reduce maintenance, and per- more realistic, lower costs, reduce maintenance, and per-mit the safety factor to be determined before construction mit the safety factor to be determined before construction starts. A probability of 10 to 90 percent of strengths being starts. A probability of 10 to 90 percent of strengths being below design strength provides better concrete than below design strength provides better concrete than obtained currently under minimum strength specifications. tained currently under minimum strength specifications.