ABSTRACT
Stress strength ratio in series 2 was found to be larger at lower W/C at any age. Cracking risk of
N35 and N30 was very low at 1 day when autogenous shrinkage stress was small, and slightly increased at 3 days. Total stress then slightly decreased due to creep, while tensile strength increased, making crack initiation less possible at 7 days. Stress strength ratio of N25 increased with age, suggesting that autogenous shrinkage stress increased at a higher rate than tensile strength. N20 was continuously subjected to high stress history from 1 day as indicated by the high stress/strength ratios in a range from 80% to 90%. However, unlike BB or other specimens, strength stayed below the cracking point, causing no cracks. These findings revealed that cracking risk due to autogenous shrinkage is low at least in concrete with high water cement ratios, low heat cement concrete and expansive concrete where autogenous shrinkage is small, although absolute values of autogenous shrinkage strain do not correspond directly to cracking.
