specifications - FAACO - Federal Aviation Administration Contract ...

3.12 SLABS; FINISHING:FTWIC-2235June, 20092. The specifications and procedures for placing concrete underwater are asspecified above for "Placing Concrete in Water."A. Finish slabs, platforms and steps monolithically and apply the following schedule offinishes:TYPE OF FINISHWood Float FinishSteel Trowel FinishBrush FinishFloor HardnerLOCATIONInitial finish for all slabs to receive trowel finishAll slabs unless otherwise notedSidewalks, exterior exposed mechanical pads.Base-EG building mechanical and electricalfloor slabs.B. WOOD FLOAT FINISH:Finish surfaces using a wood float to a true, even plane with no coarse aggregate visible.In the initial floating, while the concrete is plastic, use sufficient pressure on the woodfloat to bring excess moisture to the surface for removal. Apply a final "light float" finishto the surface as the concrete hardens. The surface shall have a uniform appearance andshall meet the straightness requirements.C. STEEL TROWEL FINISH:After all surface moisture has disappeared, following the initial wood float finish, steeltrowel surfaces to a smooth, even, impervious finish of uniform smoothness and color,free from blemishes, including trowel marks.D. BRUSH FINISH:Following the steel trowel finish, brush the surface of the concrete lightly with a softbristledbrush. Keep the brush clean and dip in water frequently so that it is clean andwet at all times. Limit brushing to necessary glaze removal and to produce a non-slipsurface.E. POWER MACHINE FINISH:Instead of hand-finishing slab surfaces requiring wood float, finish may be with anapproved power finishing machine, operated in accordance with the directions of themachine manufacturer. Following machine finishing, eliminate irregularities by handtroweling with a steel trowel. Power machine finishing may also be used as an initialstep in finishing surfaces which require a steel trowel finish. However, the entire surfaceof steel trowel finishes shall be given its final finish by hand, using a steel trowel. Wheresteel trowel surfaces are to receive a floor covering, it is not required that entire surfacebe hand troweled. In general, the preparation of surfaces for finishing by machine shallbe as required for hand finishing.F. FINISHING IN HOT, DRY WEATHER:03300-24