When designing a concrete floor slab, what should designers and contractors consider when they decide on the best way to build a floor? Usual considerations include such things as the strength of the concrete, the finish, and the spacing between joints. But there are other issues: durability, shrinkage, curling, moisture vapor transmission, and maintenance, to name a few. Cost is a big issue in the minds of owners too. The owner, architect, engineer, general contractor, concrete contractor, ready-mix producer, and the testing company must all be involved in the front-end planning process. Some prejob meetings can take most of a day just on the subject of floor construction.

The accumulation of knowledge about floor construction is happening at an accelerated rate—faster than many other segments of the concrete industry. So this supplement to CONCRETE CONSTRUCTION about slab-on-grade floor construction is designed to provide you with the latest information about building better floors.

Best In The Business

CONCRETE CONSTRUCTION has assembled what I feel is a line up of authors that are the leading authorities on the subject of slab-on-grade floors. Many of the authors are vital members of the ACI Committee 302, Construction of Concrete Floors, and ACI Committee 360, Designs of Slabs on Ground, such as Terry Fricks, Patrick Harrison, Jerry Holland, Arthur McKinney, Eldon Tipping, and Wayne Walker. Kim Basham, Michael Clark, Tim France, Howard Kanare, and Robert Simonelli round out this elite team of authors, each of which are at the forefront of slab construction.

Top-Notch Resources

Previewing the articles, we examine the most recent thoughts and findings from ACI Committee 360, Design of Slabs on Ground, and 302, Construction of Concrete Floors, concerning the design of floors and how that relates to the means, methods, materials, and site conditions. Another article addresses reinforcement for floors, including post-tensioned slab construction, nonshrinkage floors, and load transfer devices over control and construction joints. We also cover placing and finishing floors with average flatness requirements to those rated “superflat.” Green concrete floors, specifically the “Wal-Mart spec” and its new requirement to include up to 20% fly ash or slab replacements of portland cement also is addressed. The article provides information about the research being performed by Wal-Mart comparing the finishability and durability of several “greener” mixes. As such, the article also suggests how these mixes are changing finishing procedures.

This supplement takes a close look at the construction of good floor mix designs, describing how one contractor revisits his projects years after the work is in service to discover how he can refine his mixes to make them perform better over time. Learn how to produce more durable floors with less curling, shrinkage, cracking, and better wearing characteristics on the surface.

Constructing better floors isn't easy and the issues become ever more complex. One thing is certain though, the owner, designer, and contractor must all be involved and communicate regularly. Floor construction is both high tech and very basic—good communication being the most basic of all.

Tim Gregorski
Editor in Chief