Download PDF version (66.6k) Log In or Register to view the full article as a PDF document.
Q. Which is better at preventing cracks in concrete slabs: fiber reinforcement or wire mesh?

A.Robert Shuldes responds: Neither fiber mesh nor wire mesh will guarantee no cracks. In fact, a concrete slab will always crack as it shrinks during curing. By placing control joints at the proper spacing, you can limit where those cracks occur (see table of recommended joint spacing). If, however, a crack occurs where you did not expect it, wire mesh is better at keeping the crack tight and preventing it from opening up further.

Robert Shuldes, P.E., is an engineer with the Portland Cement Association.

Maximum Spacing of Slab Control Joints
Slab thickness Slump 4 to 6 in. Slump less than 4 in.
Aggregate less than 3/4 in. Aggregate 3/4 in. and larger Aggregate ¾ in. and larger
4 in. 8 ft. 10 ft. 12 ft.
5 in. 10 ft. 13 ft. 15 ft.
6 in. 12 ft. 15 ft. 18 ft.
Source: Portland Cement Association