Relationships between compressive and flexural strengths of concrete based on fresh field properties

Premature cracks are attributed to traffic-induced stresses, weather, and construction deficiencies, resulting in durability cracking, spalling, and popouts. These distresses can cause many problems, such as frequent maintenance, increased vehicle repair costs and safety concerns. Furthermore, poor road conditions can lead to vehicle crashes, which can cost billions of dollars annually and cause fatalities. Efficiently determining the strength of in-place concrete is therefore crucial for traffic safety and quality assurance. This study analyzes the fresh field properties (unit weight, air content, slump, and temperature), compressive, and flexural strengths of 1,342 concrete specimens to determine models that correlate the compressive and flexural strengths for normal strength concrete. The root mean square error was used to analyze the accuracy between the values predicted by the models and the laboratory values. Existing models reported by researchers were analyzed using the same method and compared to the proposed models developed in this study. Based on the analysis, a positive nonlinear correlation between the compressive strength and flexural strength of normal strength concrete was determined. The air content was found to be the most significant fresh field property and has a negative correlation with both the compressive and flexural strengths. The proposed regression equations exhibit small errors when compared to the experimental results, which allow for efficient and accurate predictions of the flexural strength.