Testing and Assessment of Epoxy Injection Crack Repair For Residential Concrete Stem Walls and Slab-On-Grade

The research report addresses the performance of epoxy injection crack repair in plain (i.e. unreinforced or lightly reinforced) concrete stem walls and slab-on-grade floors found in typical single-family residential construction. While the research is intended to address the efficacy of repairs in the context of possible seismic damage, the issue of cracked foundations and floor slabs has a much broader association with housing performance problems. In fact, it is ranked among the mpost common home warranty claims and home builder concerns.

Crack control methodologies are not generally employed in the construction of residential foundations and floor slabs. Thus, observable cracking in stem walls and slab-on-grade floors is common and is primarily attributable to concrete shrinkage and differential settlement. Historically, such cracks are typically ignored unless they lead to other problems. Obviously, it is desirable to repair cracks that compromise the structural performance of the foundation, although the circumstances under which that performance is compromised are not well defined. Sealing of cracks may also be desired to prevent moisture, pest, and/or potential radon infiltration into the residence.

One of the most common and popular repair methods employed to repair cracks in concrete is epoxy injection. This repair method is minimally disruptive and cost-effective because it does not require the replacement of existing concrete. While extensively tested and widely used for repair of reinforced concrete in commercial and industrial application, the performance of such repairs in typical residential applications is not well documented.

The testing program described herein addresses the effectiveness of repair for a range of typical crack widths and access limitations encountered in typical residential concrete. In particular, access for repair is limited to one side of the specimen.