ACI 309.2R

Description / Abstract: This guide does not define an acceptable level of quality, as this should be determined by the parties involved with the project. A perfectly formed concrete surface, uniformly smooth or deeply textured and essentially free of negative surface effects and color variation, is impossible to attain. Repairs to concrete surfaces are costly and difficult. The best repair work will not be as good as an original properly finished surface. Every effort should be made before and during construction to minimize repairs by establishing and maintaining quality concrete operations and adhering to acceptable consolidation procedures for producing formed concrete work. Concrete construction procedures and project costs do not always provide the conditions necessary to consistently obtain perfectly homogenous concrete free of all negative surface effects. Several negative surface effects discussed in this guide are tolerable and inherent in concrete production. Other potential causes of such negative surface effects may exist beyond those listed in this report. It is the responsibility of the specifier to indicate in the contract documents what constitutes acceptable and unacceptable negative surface effects for the various surfaces to be produced under the terms of a given contract. Surface tolerance specifications can be found in ACI 347.3R-13, Table 3.1.

To achieve any concrete finish, the designer and contractor should use the most appropriate materials and design and construction practices to minimize negative surface effects and keep them within acceptable limits. This guide should not be used as a standard for surface finishes, but rather as a guide for the identification of surface effects and their causes. Because concrete consolidation is considered an established field, current research is limited.