ACI PRC-238.1:2026

This report presents insights related to the understanding of a workable concrete for a given application, and consists of four main parts: 1) definitions related to rheology and workability; 2) critical review of the tests available to measure different aspects of workability and rheological performance of fresh concrete; 3) discussion of the factors affecting the performance of fresh concrete; and 4) examples that illustrate the application of rheology and material science to predict or improve the performance of fresh concrete in the field. Adequate workability can range from no flow (zero-slump) to liquid flow-like (self-consolidating concrete), depending on the application.