GENERAL "Surface Treatment" of structural concrete shall mean a finish which is an integral part of the structural concrete.
Surface treatments shall conform to requirements and uses
specified in this section.
EXPOSED SURFACE FINISH
Upon removal of forms, all fins and other projections shall
be removed and off sets leveled. All voids, holes, honeycomb or other damaged
surfaces shall be cleaned back to solid concrete, saturated with water and
filled with cement mortar of same composition as that used in the concrete. The
concrete shall be finished free from streaks, discolorations or other
imperfections so as to produce an extremely smooth dense and true finish of
uniform color.
This finish shall be used for all exposed formed surfaces.
UNEXPOSED SURFACE FINISH
Upon removal of forms, all voids, holes, honeycomb or other
damaged surfaces shall be cleaned back to solid concrete, saturated with water
and filled with cement mortar of same composition as that used in the concrete.
This finish shall be used for all unexposed formed surfaces.
ROUGH SLAB FINISH
Top surface of structural concrete slabs and equipment
foundations shall be level unless otherwise indicated. Screed shall be used for
all structural slabs and shall be securely and accurately set to elevations
indicated. After concrete has been consolidated by vibrating, it shall be
screeded to required level.
After screeding, and when concrete has partially hardened so
that if will retain impressions of a broom, it shall be broomed with a still
bristled broom and all laitance and scum removed. The brooming shall expose
some of the aggregate and score the surface to provide mechanical bond for
separate finish.
This finish shall be used as follows :
b) Top surface of equipment foundations
c) Top of concrete ductruns
MONOLITHIC FINISH
Monolithic finish is one produced on structural concrete
slabs which are poured all at one time with one concrete mix. Concrete for
structural slabs with monolithic finish shall be of the driest consistency
possible to work with a sawing motion of screed.
Surface that first be screeded, and than be floated to a
smooth, compact surface. Any water sheen shall be allowed to evaporate or
removed prior to floating operation by covering surface with burlap or similar
material. Spreading of cement or cement-sand mixture directly on top of
concrete will not be permitted.
After floating, the surface of concrete shall be steel
troweled to a smooth, state-like surface. Final troweling shall be done after
concrete is so hard that no mortar accumulates on trowel and a ringing sound is
produced as trowel is drawn over surface. Finish surface shall not be marked
off in areas or scored in any manner.
This finish shall be used as follows :
a.
Structural concrete floor slabs
where monolithic finish is indicated or required.
b.
Floor areas where resilient tile
finishes (asphalt, rubber, vinyl, etc.) are indicated or required.
FLOAT FINISH
Surface shall first be screeded, and then be ball floated to
a smooth, compact surface. After ball floating, surface shall be floated after
concrete has hardened sufficiently to retain the float finish and water sheen
has disappeared.
This finish shall be used as follows :
a. Structural concrete roof slabs. Finish shall be free of all depressions or projections which would prevent proper application of roofing.
b. Structural floor slabs only where specifically indicated or required.
c. Top of concrete walls, curbs, piers, pads, pedestals, and outdoor equipment foundations.
d. Manholes, sump pits, elevator pits etc. Roofs, if any, of these structures shall also have a float finish except that where such roof are integral with other concrete work, the roofs shall have the same finish as the other concrete work.
STEEL TROWEL FINISH
The same requirements apply as for monolithic finish except
that consistency of concrete shall be as used for the portion of work for which
steel troweled finish is specified.
This finish shall be used for stair treads.
This finish shall be used for stair treads.
BROOM FINISH
The surface shall first be screeded, and shall then be ball
floated to a smooth, compact surface. Following the ball floating, the surface
shall be broomed with a medium-stiff bristled broom only after the concrete has
hardened sufficiently to retain the scoring. The strokes shall be square across
the surface and shall be so made as to produce regular scoring without leaving
the surface or exposing any aggregate. The scoring shall run transverse to the
direction of traffic.
This finish shall be used for sidewalks and driveways. It
shall be used for other surfaces only if specifically indicated.
PROTECTION OF CONCRETE
Exposed surface of fresh concrete shall be protected from rain
during and after placement. All concrete shall be protected from damage during
construction operations. Exposed external corners of concrete shall be
protected with wood strips securely fastened in place. Trapaulins or other
covering shall be used when necessary, to completely enclose freshly finished
concrete.Proper protection shall be provided to prevent cement from being taken
or washed away and the concrete from being diluted during the process of
storing, handling, transporting, apportioning and mixing the materials, and
transporting, placing compacting and curing the concrete.
After placing and during early stages of hardening, concrete shall be protected from moisture loss, harmful effects of sunshine, wind, rain, running surface water and shocks.
CLEANING OF SURFACE
After concrete is placed, all exposed surfaces which have
been contaminated by concrete splashing, dripping, etc., caused by such
concrete work shall be cleaned to restore these surfaces to their original
condition.