Fibers & Reinforcement
Rebar, welded wire mesh, synthetic and steel fibres — what each controls and what it does not.
How to choose within fibers & reinforcement
Nothing in this category stops concrete cracking. Concrete shrinks as it cures and is roughly ten times weaker in tension than compression, so it cracks regardless. Reinforcement decides what happens next — whether cracks stay hairline and aligned, or open and step apart.
The split is between shrinkage control and structural capacity. Synthetic micro and macro fibres distribute through the mix and control cracking as it forms in the plastic state. Welded wire mesh sits at mid-depth and holds cracks closed after they form. Neither adds meaningful structural capacity, and neither substitutes for rebar in a designed member.
Rebar carries structural load. It is sized in eighths of an inch, specified under ASTM A615 for carbon steel in Grades 40 through 100, or A706 where seismic ductility matters. Spacing and cover are engineer-specified under ACI 318 — the commonly quoted 12 to 18 inches on centre is typical residential practice, not a code number. Cover is what keeps the steel passive: ACI 318 requires 3 inches where concrete is cast against earth.
What this category covers
- Synthetic macro fibres
- Synthetic micro fibres
- Steel fibres
- AR glass fibres
- Rebar — black, epoxy-coated, GFRP
- Welded wire mesh
- Post-tension systems
Standards that govern it
- ASTM A615/A615M — Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
- ACI 318 — Building Code Requirements for Structural Concrete and Commentary
Manufacturers in this category
Listed alphabetically, in no order of preference. This site does not test products and does not recommend one brand over another.