Volume 4, Issue 7 (July 2007)
Strength Correlation of High Performance Concrete Using Different Sized Specimens
The length to diameter ratio (L/d) of cylindrical concrete specimens is the main factor that affects the compressive strength of concrete. A total of more than 200 molded and cored high performance concrete cylinders of 100- and 150-mm diameters with various L/d ratios were tested to failure at 28 and 105 days. The results confirmed that the concrete strength varies significantly not only with the L/d ratio, but also with the curing method, core location, and specimen size. The current ASTM Standards C 39 and C 42 correction factors underestimate the strength test results in some cases and overestimate the results in other cases, which dictate the need for revising the ASTM correction factors for the high performance concrete. Based on a nonlinear regression analysis of the test results, strength correction factors for each specimen type were presented in figures and tables along with the correction factors provided by the ASTM standards.