Macrovezels

Macrovezels, or macro fibers, are discrete, relatively long reinforcing fibers embedded in a binding matrix such as concrete or cementitious composites. They are larger than microfibers and are designed to bridge cracks and carry load after the matrix has cracked, increasing toughness and post-cracking strength.

Common macrofiber materials include steel, polymeric fibers (such as polypropylene or polyvinyl alcohol), basalt, glass, and, in some cases, natural fibers. Steel macrofibers provide high strength and stiffness but may require corrosion protection. Synthetic fibers offer good chemical resistance and lighter weight; basalt and glass provide temperature and chemical resistance with varying stiffness. The selection depends on factors such as environmental exposure, required stiffness, and workability of the concrete mix.

In concrete and cementitious composites, macrofibers improve toughness by bridging cracks, increasing energy absorption, and slowing crack propagation. They can reduce crack widths, improve impact resistance, and contribute to durability in slabs and precast elements. Performance depends on fiber length, aspect ratio, material, dispersion, and the fiber–matrix bond, as well as mixing method and dosage.

Typical applications include fiber-reinforced concrete used for floors, slabs, precast components, repair mortars, and protective overlays. Dosages vary by fiber type and performance targets, and mixing must ensure even distribution to avoid clumping.

Design and quality standards exist in several countries for fiber-reinforced concretes, with assessment based on post-cracking behavior, toughness, and residual strength. Careful selection of fiber type and proper curing are essential to maximize longevity.