Title:
Evaluation and Prediction of Concrete Durability--Ontario Hydro's Experience
Author(s):
V. R. Sturrup
Publication:
Symposium Paper
Volume:
100
Issue:
Appears on pages(s):
1121-1154
Keywords:
aggregates; air entrainment; concrete durability; evaluation; exposure; fly ash; long-time study; performance; serviceability; tests; General
DOI:
10.14359/3752
Date:
4/1/1987
Abstract:
Durability, or service performance, is one of the most important properties of concrete. Unlike strength, however, it is difficult and frequently impossible to evaluate and predict. There are numerous short-term tests that qualitatively compare relative behavior, but none reliably predict ultimate service performance. Laboratory tests attempt to simulate specific destructive mechanisms. However, to produce results quickly, conditions frequently are more severe, and therefore more destructive than service conditions. Overmagnification or poor reproduction of the exposure condition can produce misleading results. More reliable predictions can be made from long-term service records of concretes containing similar materials and proportions and subjected to similar conditions. Frequently, reliable data are either unavailable or incomplete, leaving the engineer no alternative but accelerated laboratory tests. Results from controlled outdoor exposure tests are far more reliable but require long-term planning. While exposure conditions may not be duplicated precisely, they are more closely approximated. This paper reviews Ontario Hydro's experience in predicting the durability of concrete and assessing its service performance. Included are data from 28 years of outdoor exposure studies, with accelerated laboratory tests on companion specimens and constituent materials, on air- and nonair-entrained concretes, concretes with fly ashes of variable quality and different proportions, and concretes containing aggregates of dubious quality. The results are compared with the performance of concrete in actual structures up to 50 years old. 627-387