STRUX® BT50 Synthetic Macro-Fiber Data Sheet

Synthetic Macro Fiber for reinforcement of concrete

Product Description

STRUX® BT50 synthetic macro fiber reinforcement is a high strength, high modulus synthetic macro reinforcement that imparts toughness, impact and fatigue properties to concrete. STRUX® BT50 is a patented engineered design providing superior post-crack control performance with a broad range of applications.

STRUX® BT50 Synthetic Macro Fiber reinforced concrete reliably achieves residual strength values in excess of 145 psi for every 4.5 lbs/yd3 (1 MPa for every 2.7 kg/m3). STRUX® BT50 fibers are 2 in. (50 mm) in length with an aspect ratio of 75 and are primarily designed to replace steel fibers, welded wire fabric, light rebar and other select secondary reinforcement. STRUX® BT50 is a user friendly fiber reinforcement which is easier and safer to use, compared to other types of reinforcement.

Compliance and Certification

  • ASTM C1116 / C1116M, Standard Specification for Fiber-Reinforced Concrete, Type III Synthetic Fiber-Reinforced Concrete
  • ASTM D7508 / D7508M, Standard Specification for Polyolefin Chopped Strands for Use in Concrete
  • CSA B66-16, Design, material and manufacturing requirements for prefabricated septic tanks and sewage holding tanks

Product Advantages

  • Unique packaging provides superior dispersion
  • Savings from reduced labor, material and storage costs and shorter construction time compared to secondary reinforcement
  • Enhances safety by eliminating handling of steel fibers, welded wire fabric or rebar
  • Eliminates proper reinforcement positioning concerns
  • Provides superior crack control due to the geometry and elastic modulus
  • Non corrosive
  • Controls both plastic and drying shrinkage
  • Increased crack resistance, ductility and energy absorption and toughness
  • Improved impact resistance
  • May be used to provide effective crack width control 

Primary Applications

STRUX® BT50 Synthetic Macro Fibers are engineered for ease of use, excellent dispersion and finishability in slab-on-ground flooring applications. STRUX® BT50 can be used in commercial, industrial and manufacturing floors, along with other select flat and form work applications. STRUX® BT50 is also ideal for use in precast tunnel segments and other select precast applications, pavements and soil stabilization projects, shotcrete and blast resistance. Please consult your GCP sales representative to discuss your specific application.

Addition Rates

STRUX® BT50 Synthetic Macro Fibers addition rates are dependent on the specific application and desired properties and will typically vary between 7 to 15 lbs/yd3 (4 to 9 kg/m3). Please consult your GCP Applied Technologies sales representative for the proper addition rate of STRUX® BT50 macro fibers for your application.  Always consult local building codes.

Guidelines for Usage and Compatibility with Other Admixtures

Slight mix design modifications including increases in fine aggregate contents and high range water reducer dosage rates may be required when incorporating STRUX® BT50 Synthetic macro fibers into a mix design. Each additional 3 - 4 lbs/yd3 (1.8 - 2.4 kg/m3) of STRUX® BT50 may reduce the slump of the concrete approximately 1 in. (25 mm). Up front addition of STRUX® BT50 into empty drums prior to batching provides optimal STRUX® BT50 dispersion in the concrete mixture. However, STRUX® BT50 may be added to the concrete at any point during the batching or mixing process. STRUX® BT50 should be mixed a minimum of 70 revolutions as specified in ASTM C94. Please consult with your GCP representative.

STRUX® BT50 Macro Fibers Physical Properties

Specific gravity 0.91
Absorption None
Modulus of elasticity 1,000 ksi (7 GPa)
Tensile strength 80 ksi (550 MPa)
Melting point 320°F (160°C)
Ignition point 1,050°F (570°C)
Alkali, acid & salt resistance High
Material 100% virgin polypropylene and polyethylene blend
Electrical and Thermal Conductivity Low
Nominal Length 2 in (51 mm)
Nominal Aspect Ratio 75
Nominal Equivalent Diameter 0.0267 in (0.679 mm)
Nominal Fiber Count 27,240 per lb (60,000 per kg)


STRUX® BT50 Macro Fibers are available in 10 lb (4.5 kg) bags.

Safety and Handling:

Read and understand the product label and Safety Data Sheet (SDS). All users should acquaint themselves with this information prior to working with the products and follow the precautionary statements. SDSs can be obtained by contacting your local GCP representative or office.

U.S. Patent No. 7,462,392
U.S. Patent No. 7,749,352 | North America Customer Service: +1 (877) 423 6491

We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation or suggestion is intended for any use that would infringe any patent, copyright or other third-party right. 

ADVA, MIRA and STRUX are trademarks, which may be registered in the United States and/or other countries, of GCP Applied Technologies Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status. 

© Copyright 2020 GCP Applied Technologies Inc. All rights reserved.

GCP Applied Technologies Inc., 2325 Lakeview Parkway, Suite 400, Alpharetta, GA 30009, USA
GCP Canada, Inc., 294 Clements Road, West, Ajax, Ontario, Canada L1S 3C6
This document is only current as of the last updated date stated below and is valid only for use in the United States. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2023-06-28