For more than a century, architects and engineers have referenced two documents to design safe, durable structures: American Concrete Institute (ACI) 318 (code requirements) and ACI 301-16 (specifications). Until recently, however, they lacked similar guidance when asked to repair or rehabilitate those structures – a much trickier proposition.
It’s impractical and unnecessarily expensive to use new-build standards when repairing an older building that’s safe and performing well. Buildings are usually occupied during repair work, raising safety issues new-build standards don’t address. As-built conditions aren’t always well-documented. Areas that need repair –a balcony or multistory-building column or group of columns in the center of a floor plate – may be isolated, raising unique structural considerations. Repair material, processes, and procedures are seemingly limitless.
In 2013, ACI took the first step toward standardizing repair and rehabilitation by releasing ACI 562-16 (code requirements). In November 2018, the organization completed the process by releasing ACI 563-18, Specifications for Repair of Concrete in Buildings.
ACI’s first performance-based code gives designers the flexibility necessary to effectively address the many contingencies associated with repair work. Rather than dictate requirements for each and every potential scenario, repair specifications use the same language as new-build specifications (ACI 301-16) – details on materials, mixing, typical reinforcement methods, and installation processes remain fundamentally the same – to create minimum requirements and optional requirements.
The document covers general requirements for all repair work: shoring and bracing; concrete removal and substrate preparation; materials and proportioning of concrete; proprietary cementitious and polymer repair materials; reinforcement; repair material production, placing, finishing, and curing; formwork performance criteria and construction; treatment of joints; embedded items; repair of surface defects; mockups; and finishing formed and unformed surfaces.
Guidance for tailoring technical drawings and specifications to communicate specific project needs are included, as are provisions for testing, evaluation, and acceptance of repair materials and acceptance of the work. Sections 9 and 10 incorporate by reference two other specifications—ACI 503.7 and ACI 506.2—to cover crack repair by epoxy injection and shotcrete, respectively.
ACI 563-18 can be tailored for any project, big or small, using conventional concrete or proprietary repair materials for any project delivery type, from traditional design-bid-build to design-build, and for both private and public projects. The clear delineation of responsibilities, QA/QC, and documentation requirements minimizes unpleasant surprises during procurement and execution for both owner and contractor.
ACI 563-18 is available for purchase in print and digital formats through ACI at www.concrete.org.
