INSPECTION & ACCEPTANCE
GENERAL
Microfibers are used to control plastic shrinkage cracks in concrete and improve slip form concrete placements, such as barrier rail. Macro fibers control cracking in hardened concrete, add toughness, and impact and fatigue resistance to hardened concrete.
REQUIREMENTS
Acceptance of synthetic fibers for concrete for use on Iowa Department of Transportation projects will be on the basis of manufacturer and brand name approval. Approved manufacturers and brands of synthetic fibers are listed in the Materials Approved Products Listing Enterprise (MAPLE) as Appendixes A and B for two types of applications. Appendix A lists the approved fibrillated and monofilament fibers, Appendix B lists approved macro structural fibers, and Appendix C lists approved microfiber/macro fiber blend.
APPROVAL
The manufacturer shall submit the following items:
1. Product identification including brand name and product number
2. A set of current product literature and complete manufacturer recommendations for usage
3. Current Material Safety Data Sheet (MSDS).
Microfibers shall meet the requirements of ASTM C1116, Type III. Fibrillated or monofilament fibers shall be ½” to 1” in length. Fibers shall contain no reprocessed olefin materials.
Macro polyolefin fibers shall meet the requirements of ASTM C1116 and ASTM D7508 with the following exceptions:
· Cut length shall be 1.25 to 2.5 inches
· Aspect Ratio shall be a maximum of 150
Pre-packaged microfiber and macro fiber blend shall be a ratio of 80% macro fibers and 20% microfibers, with a tolerance of ±5%
In addition, when macro fiber-reinforced concrete is specified for a PCC pavement overlay, macro polyolefin fibers shall be used at an addition of 4.0 pounds per cubic yard evenly distributed into the mix. If less than 4.0 lbs. per cubic yard of macro polyolefin fiber reinforcement is used in the mix, the Contractor shall provide test results showing the mix design has a residual strength of 150 psi as determined by ASTM C1609. Mixing shall be as recommended by the manufacturer such that the fibers do not ball up.
ACCEPTANCE
Acceptance is based on approved brand name.
CONTINUING APPROVAL
The manufacturer shall file a certification at the beginning of each calendar year stating that the material supplied during that year is identical to material previously tested and approved by the Construction and Materials Bureau.