Toward an Appeal for Revision on ACI Stress Block Parameters for High Strength Concrete


The continuous increase in the concrete strength has called for adapting and amending the rectangular stress block parameter values recommended by provisions. This study reviews several different mathematical stress-strain models, and adopts a numerical technique through which a complete stress-strain curve characteristic for any strength is determined. The study highlights the effect of stress-strain model on equivalent stress block parameters. The paper illustrates the variation of the new parameter values against concrete strength together with those of provisions and of other studies. For the purpose of safe, economic, and vast use; the author suggests two formulas to calculate modified stress block parameters.