Product Uses/Benefits
The general definition of a composite is a combination of different components or elements. Think of composites as a material made from two or more dissimilar (not alike) materials that, when combined, are stronger than those individual materials by themselves. Composites is defined as a combination of polymer (resin) and a fiber reinforcement. Today, the composites industry uses a more specific term: fiber reinforced polymer (FRP) composites.
A polymer is a chemical compound made of many identical components linked together like a chain. “Polymer” and “resin” are interchangeable terms. The fiber reinforcement can be glass, carbon, or aramid (Kevlar™). These fibers are very strong.
The function of the fibers is to provide strength and stiffness to the composite product where the resin acts to bond and protect the fibers from chemicals and the environment, as well as transfer load between the fibers. Composites are different than other materials. For example, metals are isotropic, meaning they have equal strength in all directions. Composites are anisotropic, having different properties in different directions. This gives composites an advantage by allowing designers to make efficient use of materials for the design loads.
Benefits of Composites for Infrastructure
FRP composites have many benefits to their selection and use. The selection of the materials depends on the performance and intended use of the product. The composites designer can tailor the performance of the end product with proper selection of materials. It is important for the end-user to understand the application environment, load performance and durability requirements of the product and convey this information to the composites industry professional. A summary of composites for infrastructure applications include:
- Lightweight
- High Strength
- Corrosion Resistant
- Low Maintenance
- Long-term durability
- Large part geometry
These basic benefits translate improved performance for the bridge engineer including:
- Product and system design can be optimized for specific loads
- Reduced structure dead load can increase load ratings on existing structures
- Increased service-life of structure
- Reduced maintenance costs due to resistance from deicing salts and other corrosive agents
- Engineered system packaging reduces field installation time
- Faster construction reduces traffic delays
- Reliability of pre-engineered systems
- Enhanced durability and fatigue characteristics as proven in related applications from other industries
- Products and systems enables value engineering that result in innovative and efficient installations
Products for Infrastructure
Today’s bridge owners are faced with unique challenges as a result of a severely deteriorating infrastructure, insufficient funding and a demanding public. A recently released study (Report FHWA-RD-01-156) funded by the FHWA, entitled “Corrosion Costs and Preventative Strategies in the United States”, estimates the annual direct cost of corrosion for highway bridges to be $6.43 billion to $10.15 billion. This includes $3.79 billion to replace structurally deficient bridges over the next 10 years and $1.07 billion to $2.93 billion for maintenance and cost of capital for concrete bridge decks. In addition to these direct costs, the study’s life-cycle analysis estimates indirect costs to the user due to traffic delays and lost productivity at more than 10 times the direct cost of corrosion. Although almost all bridge owners in the United States continue to make decisions based on lowest initial cost, it has become extremely clear that this approach does not work and in the near future more money will be spent maintaining existing structures than building new ones. The public has become intolerant of construction delays and is demanding structures that will last longer and provide greater value for their tax dollars. As a result, there are tremendous opportunities for FRP bridge decks that are corrosion resistant, lightweight, and can be rapidly installed.
A myriad of FRP products are available for either the repair or replacement of existing bridges. Most that have been extensively demonstrated and used around the world. Examples of FRP composite products include:
- Vehicular bridge decks and pedestrian bridge systems
- FRP rebars and tendons for concrete reinforcement
- FRP composite systems for repair and strengthening, and seismic retrofit for beams, columns, slabs and walls
- Piling products and systems for marine waterfront structures
- New structural shapes applied to beams for bridge decks
Contact Us
Thank you for visiting our site. If you have any questions regarding composites used in the infrastructure market, contact John P. Busel, Director, Composites Growth Initiative at jbusel@acmanet.org or phone 914-961-8007.
