Fiber-Reinforced Concrete Overlays for Bridge Structures

About the report:

The common distresses in bridge decks are the loss of surface texture due to traffic and poor construction practices that result in cracks and spalls because of the reinforcement corroding. The common repair procedure for such distresses is removing the top surface of the deteriorated concrete and placing a low-permeability concrete overlay. Sometimes, these overlays exhibit cracks, diminishing the intended purpose of resisting the penetration of water and chloride solutions. Such cracks can occur in concrete overlays at early and late ages. However, the selection of ingredients, proportioning, and the addition of fibers to concrete can control cracks. Fiber-reinforced concretes (FRC) achieve varying levels of strength and ductility by adjusting the mixture design, including the types and amounts of fibers to address cracking occurring at different ages. This research emphasized the potential of using FRC as a versatile construction material, enabling tailored strength and durability properties to specific situations. Two groups of concretes with fibers were investigated—one with some residual strengths denoted as FRC and the other with deflection hardening properties denoted as high-performance FRC, or HPFRC. The findings of this research contribute to the understanding of FRC performance and guide the selection of optimal mixture designs with fibers to control cracking and improve the longevity and performance of concrete overlays. The practical outcome of this study is the recommendation that the Virginia Department of Transportation should use FRC to control cracking in overlays as needed, feasible, and practical.

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