Influence of Aggregate and Proportions on Flowing Concrete Characteristics

Project Details
STATE

MI

SOURCE

ACI

END DATE

03/01/18

RESEARCHERS

Trejo, David; Hendrix, Greg

SPONSORS

American Concrete Institute

KEYWORDS

Air voids; Cast in place concrete; Flow; Fresh concrete; Piles (Supports); Plastic flow; Cast in drilled hole; bridge piles

LINKS

Products

Project description

Cast-in-drilled-hole (CIDH) piles are often constructed to depths that are inaccessible, and internal vibration is not performed over the length of the pile. Because of this, the likelihood of voids occurring increases. Many state highway agencies use inspection pipes to detect if voids are present along the length of the pile. High reinforcement densities and concrete void detection inspection pipes can congest CIDH piles. Although concrete void detection and reinforcement spacing are critical to ensuring adequate CIDH pile structural performance, eliminating concrete voids can also ensure expected performance. This research will assess the influence of coarse aggregate (CA) type and mixture proportions on concrete workability for CIDH pile applications. Results indicate that identifying an optimal paste volume-to-aggregate void ratio (PV/AV) can be used to proportion flowing concrete (FC) mixtures with adequate slump flow and stability. Concrete containing rounded CA achieved higher slump flow values than concrete with crushed CA at the same paste volume. However, increasing PV/AV also decreased stability. Stability was increased by increasing the FA-to-CA ratio (FA/CA).
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