The determination of resistance reduction factors to account for material variability in the development of Load and Resistance Factor Design (LRFD) codes depends on the statistics of the materials involved. This paper summarizes the results of a statistical analysis on steam-cured plant-produced high strength concrete in compression based on 399 specimens obtained from concrete producers in Pennsylvania. The seasonal effect on the mean-to-nominal ratio, coefficient of variation, and probability distribution shape is also considered. Statistics on cylinder strengths are used to predict the variability of in-situ concrete. The results of the analysis show that high strength concrete has superior statistical properties compared to conventional concrete due to better quality control measures. The study will help code developers and engineers in the generation of probabilistic resistance models for structures made with high strength concrete.
