Portland-cement concrete rheology and workability : final report

Methods for determining the workability of freshly mixed portland-cement concrete with slumps less than 51 mm (2 in.) were investigated. Four potential methods to determine the workability of concrete were proposed for evaluation and development. The methods included two moving-object methods, one free-orifice method, and a vibrating-slope method. The report outlines modifications to these existing techniques and equipment to permit the measurement of rheological properties at two or more shear rates. The vibrating-slope apparatus was selected for further development.