Polyurethane Foam Infill for Fiber-Reinforced Polymer (FRP) Bridge Deck Panels

Two graduate students

The objective of the proposed research is to develop, test, and evaluate fiber-reinforced, polyurethane foams to replace the costly honeycomb construction currently used to manufacture FRP bridge deck panels. The effort will focus on developing an FRP sandwich panel to replace the precast, stay-in-place forms currently used to construct reinforced concrete bridge decks.

Although still in their infancy, fiber reinforced polymer (FRP) bridges have shown great promise in eliminating corrosion concerns and meeting (or exceeding) FHWA’s goal of 100-year life spans for bridges. While FRP bridges are cost-effective in terms of life cycle analyses, the combination of higher first costs and limited state DOT budgets has restricted their use. One area that has shown some headway is the use of FRP for bridge decks, focusing on the location where the majority of corrosion-related damage normally occurs. However, first costs still hamper widespread use of this approach.

FRP bridge deck panels offer superior corrosion resistance, at one-fifth the weight of reinforced concrete. However, current FRP bridge deck panels typically rely on an intricate geometric honeycomb system between the top and bottom layers of the sandwich panel. This labor-intensive honeycomb construction doubles the cost of FRP panels compared to reinforced concrete. Although cost-effective in terms of longevity of the bridge and overall reductions in weight, the lower first cost of reinforced concrete precludes the use of FRP bridge decks in the majority of situations.

Closed-cell, high-density polyurethane foams lower first cost, offering a cost-effective alternative to the complex honeycomb construction. Structural sandwich panels with a polyurethane foam infill are well established in other commercial applications, such as automobiles, aircraft, and prefabricated buildings. Several recent advances in polyurethane foam formulations have resulted in a material that can resist the localized compressive stresses and fatigue loading beneath a truck wheel, making this type of sandwich panel construction a viable alternative for bridge decks. Once these panels can compete against reinforced concrete on a first-cost basis, their significantly longer life expectancies will save considerable money for MoDOT and the residents of Missouri.

The first step in establishing FRP sandwich panels as a viable option will be to examine the potential of using them to replace the precast, stay-in-place forms currently used to construct reinforced concrete bridge decks. The sandwich panel will serve as formwork for the concrete placement and act compositely with the hardened concrete under subsequent dead and live loading. As part of the sandwich panel development, S&T will evaluate polyurethane foam formulations, panel configurations (overall shape, jointing, end bearing), panel fiber architecture, panel durability, and methods of developing composite action with the concrete.

Anticipated Benefits

Cost effective, corrosion-resistant bridge decks

Milestones

Relationship to other Research/Projects

This is a standalone project under the advanced materials theme of the Center for Transportation Infrastructure and Safety (CTIS) National University Transportation Center (NUTC) at Missouri S&T.

Technology Transfer Activities

The technology transfer activities will include a final research report and dissemination of the findings through a national conference via technical presentation(s) and publication(s).

Transportation Research Board Keywords

Advanced Materials, Bridge Decks, Composite Materials, Corrosion Mitigation, Fiber-Reinforced Polymers