Digg This
Talk Back
Post a Comment
|
HousingZone Most Popular Stories
- Kitchen & Bath Trends for 2010
- 2009 Best in American Living Awards Reveal What's Ahead for Residential Design
- Record 2009 Foreclosures Despite Aid
- FinestExperts Ranks Top 2010 Real Estate Investment Markets
- 2010 Brings New Lows in Home Price Reduction Levels
- Short sales unlikely to harm housing market
- Earth Advantage Institute Selects Top 10 Green Building Trends For 2010
- U.S. Apartment Vacancy Rate Hits 30-Year High
- Remodelers' Exchange: Rental properties can be a road to success
- 100 Best New Products 2009
Fibrous Concrete Reinforcement
January 27, 2000
HousingZone
Summary
Today, synthetic-fiber reinforcement is available to reinforce non-structural concrete applications with superior results, according to manufacturers. Currently, the most widely-accepted form of reinforcement is welded-wire fabric (WWF), a mesh of thick steel wires that is placed concrete. However, synthetic-fiber reinforcement avoids the increased labor costs and difficulty in placement that are associated with WWF.
Details
Synthetic-fiber reinforcement prevents cracks in concrete, unlike WWF, which controls crack width -- cracks actually need to occur before the WWF goes to work. Small-diameter synthetic fibers (nylon and polypropylene) are now being added to concrete to reduce shrinkage cracking by more than 80% according to independent lab tests. Reducing cracks lowers concrete permeability, increases its toughness and long-term weatherability, and can reduce callbacks in concrete slab floors, decks, driveways, and walks. According to fiber manufacturers, the placement, curing, or finish characteristics of the concrete are not affected by the addition of fibrous reinforcement.
Larger-diameter synthetic fibers (steel and polyolefin), added at higher content by volume (0.5% to 1.5% respectively), also enhance hardened flexural strength, but at increased cost.
Installation
Benefits/Costs
Fibrous reinforcement reduces concrete slab cracking, permeability, and flaking or spalling. Increases in impact resistance, strength, and durability claims vary by manufacturer. Uniform distribution of fibers through the concrete mixture assures proper placement of the reinforcement, often an issue with WWF. Fibrous reinforcement is reported to add as little as $7 to $10 per cubic yard of ready mixed concrete, which is about the same cost as material and labor to place WWF. One performance-enhancing product with a significantly higher fiber content, can add $50 to $60 per cubic yard.
Limitations
Fibrous reinforcement is primarily used to reduce cracking in non-structural concrete applications. Steel fibers rust and can cause surface discoloration. Although higher fiber content by volume improves performance, it costs more and has a greater potential for creating dense concentrations of fibers in the concrete which can lead to problems.
Code/Regulatory
All manufacturers attest to compliance with ASTM C 1116-95, which provides the specification for Fibrous Reinforcement. The Residential Concrete Code for One and Two Family Dwellings, ACI Committee 332 (Draft) allows use of WWF and Fibrous Reinforcement in nonstructural concrete applications. The CABO One and Two Family Dwelling Code (1995) no longer specifies a minimum amount of WWF or equivalent reinforcement to be used in concrete floors on grade.
Availability
Fibrous reinforcement is generally sold directly to ready mixed concrete suppliers. The suppliers add the fiber product to the concrete during the mixing process. Some of the higher performance and more costly products are sold directly to users for a specific project with relatively large requirements. Some ready mixed concrete suppliers have assisted with addition of more costly fibers for small projects.
Contact(s)
Do you have a specific question about this technology and/or its 'real life' applications? Try the contacts listed below:
3M (Polyolefin)
3M Center 251-2A-09
St. Paul, MN 55144
612-737-9705
Nycon, Inc. (Nylon)
101 Cross St.
Westerly, RI 02891
800-456-9266
http://www.nycon.com/
Novocon (Steel)
1220 Central Avenue
Hanover Park, IL 60103
800-424-3340
http://www.novocon.com
Fibermesh (Polypropylene)
4019 Industry Drive
Chattanooga, TN 37416
800-635-2308
http://www.fibermesh.com/
© 2010, Reed Business Information, a division of Reed Elsevier Inc. All Rights Reserved.
