New Mixture Proportioning Method for Flowing Concrete Mixtures
Greg Hendrix and David Trejo
Appears on pages(s):
flowability; flowing concrete; mixture proportioning; passing ability; stability; workability
There is a demand for flowing concrete (FC) in concrete structures that are inaccessible and have congested reinforcement. Although mixture proportioning methods are available for conventional concrete (slump < 7 in. [178 mm]) and for self-consolidating concrete (very high slump values and high flow), until recently, a rational method for proportioning FC has not been available. There is a knowledge gap for proportioning FC mixtures (slump > 7.5 in. [190 mm]). The mixture proportioning method presented herein involves quantitatively assessing the coarse aggregate (CA) shape and packability along with the combined aggregate void (AV) content to proportion FC mixtures. The aggregate characteristics can be used to determine the fine aggregate (FA)-to-CA ratio (FA/CA) that results in a minimum aggregate void content. Using this minimum void content and the aggregate characteristics, the paste volume for flowable concrete trial mixtures can be estimated. This research determined that the past volumen (PV)-to-AV ratio (PV/AV) significantly influences the slump flow and VSI (stability) but does not significantly influence the J-ring passing ability for the mixtures assessed in this research. Results indicate that FC mixtures with adequate flowability, stability, and passing ability can be proportioned using this method.