At times cracks do develop in concrete members due to several reasons such as design of construction deficiency, problems with concrete, disturbance at early stage, etc. If such cracks are localized in nature they can be repaired either by epoxy grouting or by stitching. The choice of either of them depends on the discretion of the concerned engineer and the intensity of the cracking (Gambhir, 2010).
Stitching consist of drilling holes on both sides of the crack, and inserting U-shape metallic strips (stitching dogs) spanning across the cracks. The bonding of the metallic strips with parent concrete can either by with non-shrink grout or epoxy-based bonding system. It is preferable if the metallic strips are variable in length and orientation with closer spacing at the ends of cracks (Fig. 30.6).
Figure 30.6 Stitching of concrete cracks
However, stitching does not close a crack, but only prevents it from further widening. Such stitches, when encased with an overlay have been reported to be performing well in several cases.
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