Is Fiber Mesh Better Than Wire Mesh for Concrete?

Wire Mesh

• Control joints are pre-selected cracks in the concrete. By determining where the cracks will occur in advance, builders can minimize the damage shrinkage cracking might otherwise cause. Wire mesh enables builders to put the control joints farther apart than they would otherwise. Excessively wide spacing for control joints permits shrinkage cracks to form in other places between the joints, but now the wire mesh holds the concrete on either side of the joint together.

Plastic Fibers

• Plastic fibers actually fulfill a different role than wire mesh. The plastic fibers do not affect the control joint spacing; builders will still need to select control joint locations as they would under ordinary circumstances. The plastic fibers, however, will reduce the amount of shrinkage cracking that takes place. Usually the plastic fiber content is about 0.1 percent by volume, and polypropylene is one of the more common materials.

Comparison

• The control joint spacing for plastic fiber concrete is the same as the control joint spacing for ordinary concrete. Wire-mesh concrete, by contrast, can have a wider control joint spacing. Although their ultimate function is to help control cracking, wire mesh and plastic fiber do not fulfill the same role. You should not use plastic fiber to replace wire mesh, because it does not serve the same purpose.

Considerations

• It's important to bear in mind that neither product is intended to increase the load-bearing capacity of the concrete. The only reason to use wire mesh is if you need to space the control joints farther apart than you normally would due to joint maintenance, which is usually due to slabs with an unusual shape or flatness, for example. Plastic fiber is something you would use if you are concerned about plastic shrinkage cracking and want to minimize it in a particular application.