In this article, ACI Fellow Kim Basham outlines best practices for evaluating cracks in concrete before designing or conducting repairs. Critical evaluation factors include crack width, dormancy and reinforcement materials.
Cracks may represent the total extent of damage or the first signs of serious trouble. Some recommendations for troubleshooting concrete cracks prior to designing or performing repairs.
Cracking is a natural, expected, and accepted behavior of concrete. However, cracks may affect the appearance, function, durability, service life, or more seriously, the structural integrity of the concrete. For these reasons, designers, concrete producers, and contractors are always trying to control or minimize the amount and severity of concrete cracking. However, crack-free concrete is seldom achievable, especially for standard unreinforced or reinforced concrete.
For some projects, the specifications require cracks in concrete to be repaired and may specify a crack repair procedure or may simply require cracks to be repaired as directed by the engineer. Regardless of what is required by the specifications, cracks should be investigated before designing or performing repairs, especially for elevated structures.
Otherwise, repairs may not address the root cause of cracks resulting in poorly repaired cracks that fail prematurely or repairs that may not restore the as-designed condition of the structure. More importantly, a proper investigation can determine if a crack is the first sign of serious trouble indicating the load-carrying capacity of the structure may be jeopardized by either a design, detailing, or construction error.
Here are some recommendations for troubleshooting concrete cracks prior to designing or performing repairs.