Guide for Concrete Floor and Slab Construction
|Publication Date:||22 October 1996|
Purpose and scope
This guide presents state-of-the-art information relative to the construction of slab-on-ground and suspended-slab floors for industrial, commercial, and institutional buildings. It is applicable to the construction of normal weight and structural lightweight concrete floors and slabs made with conventional portland and blended cements.
The design of slabs on ground should conform to the recommendations of
ACI 360R. Refer to ACI 223 for special procedures recommended for the
design and construction of shrinkage-compensati
This guide identifies the various classes of floors as to
*design details as they apply to construction,
*necessary site preparation, and
*type of concrete and related materials.
In general, the characteristics of the concrete slab surface and the performance of joints have a powerful impact on the serviceability of floors and other slabs. Since the eventual success of a concrete floor installation is greatly dependent upon the mixture proportions and floor finishing techniques used, considerable attention is given to critical aspects of achieving the desired finishes and the required floor surface tolerances. This guide emphasizes choosing and proportioning of materials, design details, proper construction methods, and workmanship.
Prebid and preconstruction meetings--While this guide does provide a reasonable overview of concrete floor construction, it should be emphasized that every project is unique, circumstances can dictate departures from the recommendations contained here. Accordingly, contractors and suppliers are urged to make a thorough formal review of contract documents prior to bid preparation.
The best forum for such a review is the prebid meeting. This meeting offers bidders an opportunity to ask questions and to clarify their understanding of contract documents prior to submitting their bids. A prebid meeting also provides the owner and the owner's designer an opportunity to clarify intent where documents are unclear, and to respond to last-minute questions in a manner that provides bidders an opportunity to be equally responsive to the contract documents.
The preconstruction meeting should confirm and document the responsibilities and anticipated interaction of key participants involved in floor slab construction. Following is a list of agenda items appropriate for such a meeting; many of the items are those for which responsibility should be clearly established in the contract documents. The list is not necessarily all-inclusive.
1. Site preparation
2. Grades for drainage, if any
3. Work associated with installation of auxiliary materials, such as vapor barriers, vapor retarders, edge insulation, electrical conduit, mechanical sleeves, drains, and embedded plates.
4. Class of floor
5. Floor thickness
6. Reinforcement, when required
7. Construction tolerances; base (rough and fine grading), forms, slab thickness, surface configuration, and floor flatness and levelness requirements (including how and when measured)
8. Joints and load transfer mechanism
9. Materials: cements, fine aggregate, coarse aggregate, water, and admixtures (usually by reference to applicable ASTM standards)
10. Special aggregates, admixtures, or monolithic surface treatments, where applicable
11. Concrete specifications, to include the following:
a. Compressive and/or flexural strength and finishability (Section 6.2)
b. Minimum cementitious material content, if applicable (Table 6.2.4)
c. Maximum size, grading, and type of coarse aggregate
d. Grading and type of fine aggregate
e. Air content of concrete, if applicable (Section 6.2.7)
f. Slump of concrete (Section 6.2.5)
g. Water-cement ratio or water-cementitious material ratio
h. Preplacement soaking requirement for lightweight aggregates
12. Measuring, mixing, and placing procedures (usually by reference to specifications or recommended practices)
13. Strikeoff method
14. Recommended finishing methods and tools, where required
15. Coordination of floor finish requirements with those required for floor coverings such as vinyl, ceramic tile, or wood that are to be applied directly to the floor
16. Curing procedures, including length of curing and time prior to opening the slab to traffic (ACI 308)
17. Testing and inspection requirements
18. Acceptance criteria and remedial measures to be used, if required
Additional issues specific to suspended slab construction are as follows:
1. Form tolerances and preplacement quality assurance survey procedures for cast-in-place construction
2. Erection tolerances and preplacement quality assurance survey procedures for composite slab construction; see ANSI/ASCE 3-91 and ANSIASCE 9-91 (Section 12.1)
3. Form stripping procedures, if applicable
4. Items listed in Section 3.3
Quality control--Adequate provision should be made to ensure that the constructed product meets or exceeds the requirements of the project documents. Toward this end, quality control procedures should be established and maintained throughout the entire construction process.
The quality of a completed concrete slab depends on the skill of individuals who place, finish, and test the material. As an aid to assuring a high-quality finished product, the specifier or owner should consider requiring the use of prequalified concrete contractors, testing laboratories, and concrete finishers who have had their proficiency and experience evaluated through an independent third-party certification program. ACI has developed programs to train and to certify concrete flatwork finishers and concrete testing technicians throughout the United States and Canada.