Title:
Optimizing Mixture Proportions for Flowable
High-Performance Concrete via Rheology Tests
Author(s):
Chao-Wei Tang, Tsong Yen, Chao-Shun Chang, and Kuan-Hung Chen
Publication:
Materials Journal
Volume:
98
Issue:
6
Appears on pages(s):
493-502
Keywords:
flow; high-performance concrete; rheology.
DOI:
10.14359/10852
Date:
11/1/2001
Abstract:
Several series of tests involving various binder combinations, water-binder ratios, and high-range water-reducing admixture-binder ratios were conducted to optimize mixture proportions for flowable high-performance concrete (HPC). Test methods used include the standard slump, slump-flow spread, and rheology test procedures. Test samples were made with freshly mixed paste, mortar, and concrete. Measured data were used to calculate volumetric fractions of coarse aggregate and filling ratios of sand and to correlate the flow characteristics of tested paste, mortar, and concrete. The analytical results indicate that a slump value of at least 235 mm and slump-flow spread of 500 mm or more under conditions where there is no aggregate segregation are considered viable indicators for producing flowable HPC. In fact, flowable HPC does behave like Bingham fluid, and its flow behavior can be characterized by two Bingham parameters g and h that can be calculated from torque T and rotational speed of spindle N measured during the rheology tests using the flow of HPC meter (FHPCM) of the authors’ design. A slump range of 235 to 270 mm and a slump-flow spread range of 520 to 750 mm verified by rheology test data are recommended for reference in optimizing mixture proportions for flowable HPC.