Title:
Fiber Synergy in Fiber-Reinforced Self-Consolidating Concrete
Author(s):
Moncef Nehdi and Jennifer Duquette Ladanchuk
Publication:
Materials Journal
Volume:
101
Issue:
6
Appears on pages(s):
508-517
Keywords:
fibers; flexure; slump; strength
DOI:
10.14359/13490
Date:
11/1/2004
Abstract:
Self-consolidating concrete (SCC) decreases construction time, labor, and equipment needed on construction sites; makes the construction of heavily congested structural elements and hard-to-reach areas easier; reduces noise and injuries related to vibration work of concrete; and helps achieve higher-quality finish surfaces. Fiber reinforcement can extend the technical benefits of SCC by also providing crack bridging ability, higher toughness, and long-term durability. The use of steel and synthetic fibers, however, is known to alter the flow properties of fresh concrete. To maintain self-consolidating ability, the fiber length and total volume must be controlled, which can restrict the gain in toughness imparted by fibers. Thus, fibers intended for use in SCC need to be carefully optimized. This research investigates potential synergistic effects in SCC incorporating different steel and synthetic polymer macro- and microfibers in various hybrid (single, binary, and ternary) combinations. A total of 31 SCC mixtures were made with combinations of fibers in varying proportions from 0.25 to 1.0%. The fiber length varied from 30 to 50 mm for the macrofibers, while microfibers were approximately 12 mm long. The workability of each mixture was evaluated using the slump flow and L-Box flow tests. Moreover, compressive strength, first-crack strength in bending, flexural toughness, and post-first-crack behavior were investigated. The results of this research indicate that fibers can have rheological and mechanical synergistic effects, and that optimized fiber combinations can better increase toughness and flexural strength while maintaining adequate flow properties for fiber-reinforced SCC.