Title:
Concrete Strength Variability and Mix Design for Large Concrete Paving Projects
Author(s):
Greer
Publication:
Web Session
Volume:
ws_2021_Greer_ConcreteStrength.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
4/1/2021
Abstract:
Concrete for large pavement construction projects is normally paid for based on flexural strength of concrete test beams prepared during the field production of the concrete and the in-place thickness of the concrete pavement relative to the design thickness. The variability of flexural strength test results and the sensitivity of payment to these results makes the laboratory mix design very important for all parties involved with the project. The procedures utilized for the laboratory mix designs for a large concrete paving project that required approximately 450,000 cubic yards of concrete are presented and analyzed. Nine combinations of materials were evaluated at various cement factors. Regression analyses were used to establish 95% lower confidence limits for the flexural strength versus cement factor in the laboratory. The confidence limit curves were used to establish requirements for the field production. The results of the field production and testing are also presented and compared to the results of the laboratory mix design process.