Facts on Frequently Asked Questions

What is Steel Fiber Reinforced Concrete? (SFRC)
Steel fiber reinforced concrete is comprised of hydrolic cements containing fine and course aggregates and steel fiber. A superplasticizer is often used to enhance the mix workability. Steel fiber products are available in a variety of types and sizes from various manufacturers. The underlying principle however on all SFRC designs is to provide discontinuous reinforcement and effective crack control.

How do Steel Fibers work?
Steel fibers reinforce in three dimensions throughout the entire matrix. They restrain micro-cracking and act as tiny reinforcing bars. The earlier a crack is intercepted and its' growth inhibited, the less chance it will develop into a major problem.

How is concrete improved by using Steel Fibers?
Compared to plain or conventional reinforced concrete the most noticeable differences are improved ductility and post crack performance. Shorter fibers with a high fiber count offer superior first crack strength and better fatigue endurance. For ground supported slabs we highly recommend the 1" deformed fiber with a high fiber count.

What concrete properties does Flex-Ten® Fiber improve?

FLEXURAL STRENGTH: 1 1/2 to 3 times increase in first crack and flexural bending strength can be achieved over plain concrete using a 1" fiber.
FATIGUE RESISTANCE: The fatigue strength of steel fiber concrete is 1 1/2 times that of conventional concrete.
IMPACT RESISTANCE: Steel fibers greatly increase concrete's resistance to damage from heavy impact.
SHRINKAGE: Steel fibers themselves do not affect the shrinkage rate but they do minimize and help eliminate shrinkage cracks.
ABRASION RESISTANCE: Steel fibers offer a high degree of protection against abrasion and goughing along with any spalling being greatly reduced.
PERMEABILITY: By effectively reducing the micro cracking SFRC will reduce the overall porosity of the matrix, making the concrete less permeable.
WHAT ABOUT CRACKING? Concrete has always been an unpredictable material and no methodology can entirely eliminate cracking. Using SFRC offers an extremely effective means of controlling cracks. This together with proper sub-base preparation, joints and curing are all essential to overall job performance.

How does SFRC lower costs over the installation life?
Depending on the quantity and complexity of reinforcement in traditional design, SFRC can offer substantial costs savings. The superior performance of steel fiber will often reduce maintenance over the installations life, thus reducing the project cost.

What is the typical dosage rate?
SFRC dosage rates depend on the application of the concrete properties required. Typically 40 lb. to 100 lb. will satisfy most requirements. Lower dosages tend to be used when replacing conventional wire mesh. At higher concentrations SFRC will meet the most demanding requirements.

Do steel fibers affect the slump of concrete?
Adding steel fibers, particularly at higher concentrations, will give rise to an apparent loss as measured by the slump test. It is recommended that a super plasticizer be added to increase the slump 1-2" greater than the final desired target slump.

How are fibers added to the concrete?
Fibers can be added at the batch plant by depositing onto an aggregate conveyor. They can also be added to a transit mixer on site by use of a lightweight conveyer attached directly to the back of the vehicle.

What is the difference between synthethic and steel fibers?
Synthetic fibers help control plastic shrinkage cracking which can occur in the very early stages of concrete drying. Steel fibers reinforce the concrete in its' hardened state, thereby improving its' strength and durability.

The major difference between steel and synthetics is their respective Youngs modulus and tensile yield strength. Steel fibers have a sufficient high modulus of elasticity and tensile strength to assume excess strain across a crack and hold it tightly.

Copyright 2006
D&C Supply Co., Inc.
335 Washington Avenue
Bridgeville, PA 15017
(412) 221-1191