01024704

Component

https://doi.org/10.3141/1979-04

http://scholar.google.com...nson&publication_year=2006

The objective of this study was to investigate the effects of different mixing processes, particularly a two-stage mixing process, on fresh and hardened characteristics of pastes and concrete. Characteristics studied for pastes included rheological effects (i.e., yield stress, thixotropy, viscosity, and peak stress) and compressive strength for mixes prepared in a Hobart mixer and a high-shear mixer. Parameters measured for the concrete study included fresh concrete air and slump, compressive strength, and hardened concrete air void characteristics. The paste study results show that for increased mixing time, the compressive strength is not significantly influenced. The rheology results show that longer mixing times with a high-shear mixer lead to lower viscosity, thixotropy, and peak stress; this indicates better-mixed slurry when compared with a shorter mixing time and the Hobart mixer. The fresh concrete made with the two-stage mixing process shows reduction in air content, and the hardened concrete shows little change in compressive strength when compared with the concrete produced with the one-step mixing process. Rapid air void analysis results indicate that the two-stage mixing method may be beneficial for mixes containing portland cement as a sole binder in freeze–thaw durability.

01039954

English

pp 12-20

2006

Transportation Research Record: Journal of the Transportation Research Board

0309099897

Print

Figures (7) ; References (9) ; Tables (6)

Air content; Air voids; Binders; Cement paste; Compressive strength; Concrete mixing; Consistency; Freeze thaw durability; Fresh concrete; Mixers; Mixtures; Performance; Portland cement concrete; Rheology; Slurry; Thixotropy; Time; Viscosity; Yield stress

Hardened concrete; Peak stress; Slump; Two-stage concrete mixing

Highways; Materials; I32: Concrete

TRIS, TRB

Mar 3 2006 10:56AM

• Activation Energy of Alkali–Silica Reaction and Dilatometer Method
• Assessment of Flowable Fill Strength in Pavement Construction
• Capping Systems for High-Strength Concrete
• Comparison of Flatbed Scanner and RapidAir 457 System for Determining Air Void System Parameters of Hardened Concrete
• Effects of Base Type on Modeling Long-Term Pavement Performance of Continuously Reinforced Concrete Sections
• Efforts to Improve Durability of Concrete in Virginia
• Evaluation of Mechanical Properties for Self-Consolidating, Normal, and High-Performance Concrete
• Investigation into Potential of Alkali–Acetate–Based Deicers to Cause Alkali–Silica Reaction in Concrete
• Long-Term Effects of Magnesium Chloride and Other Concentrated Salt Solutions on Pavement and Structural Portland Cement Concrete: Phase I Results
• Measurement of Volume Change in Cementitious Materials at Early Ages: Review of Testing Protocols and Interpretation of Results
• Mitigating Alkali–Silica Reaction in Concrete Containing Recycled Concrete Aggregate