ACI 347.3R-13 Guide to Formed Concrete Surfaces

ACI 347.3R-13 Guide to Formed Concrete Surfaces. 3.1—General Tables 3.1a through 3.1d defne the various measurable properties pertaining to formed concrete surface texture, surface void ratio, color, fatness, and joints. Four concrete surface categories (CSCs) are defned in Table 3.1a. CSC1 has the lowest classifcations and CSC4 the highest for a fnished surface. The individual constituents used to defne each CSC are further described in Table 3.1b. The classifca- tion for form-facing materials is described in Table 3.1c. The surface void ratio is defned and categorized according to net pore area in Table 3.1d. Concrete surface levels are specifed for individual parts of the structure to refect the owner’s needs, desires, and budget. Possible examples include: a) Basement walls: CSC1; b) Industrial structures: CSC1 or CSC2; c) Electrical and mechanical rooms: CSC1 or CSC2; d) Stairwells: CSC1, CSC2, or CSC3; e) Commercial building exteriors: CSC3; f) High-end commercial building exteriors: CSC3 or CSC4; g) Religious structures or museums: CSC3 or CSC4; h) Monumental or landmark structures: CSC4. These examples are only provided to illustrate the various classifcations of concrete surfaces and are not recommenda- tions of the committee. Concrete surface fnish schedules should be designated as part of the contract documents in drawings or by designa- tions on exterior/interior views of the structure. 4.2—Design and construction recommendations Requirements for the formed concrete surface can only be met if it is possible to place and consolidate the concrete properly. The following are design and construction recom- mendations (Refer to Table 3.1a): a) Evenly arrange pouring windows and make sure they are of suffcient size to permit concrete placement. Pouring windows are openings in the formwork for placing concrete when placement from the top is not possible. Consider other compaction methods or mixture design modifcation— for example, SCC or high-fowable concrete—if pouring windows cannot be installed in the formwork without affecting areas exposed to view. Consider the locations and forming details of pouring windows in CSC2 and CSC3. Pouring windows are not recommended for CSC4. 4.4—Formwork and facing selection 4.4.1 General considerations—Consider commonly available formwork systems and how the selected system will affect project cost, design, and level of craftsmanship required. Both job-built formwork (Fig. 4.1c and 4.1d) and premanufactured formwork systems are used to construct structures. The formwork designer should consider the avail- able form system properties and coordinate the structure’s features with the characteristics of the specifc systems being considered...