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Industrial High Tolerance
Floors
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Screed Construction
Construction of High Tolerance High Quality Concrete Floor over an Existing
Floor between guide rails for Narrow Aisle Racking System, or on a roof slab as
a repairing screed:
1. Concrete existing surface to be cleaned and free of laitance & loose
materials. All floor joints are to be marked & cleaned , chipping all high
points & edges.
2. The original design of floor bays is carried out in a way to insure that
construction joints are inside the guide rails ( racking bays ) and / or the
partition walls and not in the truck aisle and all rooms.
3. Steel Guide Rail angles / form construction are fixed to the base floor by
high strength bolts.
4. Before casting of concrete, a bonding agent is applied on the existing re-
cleaned slab surface, to insure the bond between old & new concrete
leveling screed. If the use of this technique is impossible due to isolation
requested, dowel bars are placed near the form construction in order to insure
that no rising of the slab edges will take place.
5. Concrete Specifications:
Compressive Cube Strength after 28 days=25.00-30.00N/sq.mm. Coarse aggregate
washed dolomite 0---20mm. & 0---14mm in case of screed thickness less than
5 cm.
Fine aggregate 44 % of the complete aggregate quantity.
Additives for increasing retardation & workability.
Slump at casting 100.00 --- 120.00mm.
Water/Cement ratio 0.45 --- 0.50.
6. Concrete, mixed with multifilament polypropylene FIBERMESH with a
consumption 900gm/m3, is casted by direct shoot from the truck mixer to the
painted existing concrete, based on the entrance of the truck mixers inside
casting location, leveled & screeded by Magnesium stay-true straight
edge.
7. Dry shake surface hardener material may be used as an option for the
increasing of surface abrasion resistance and improvement of the anti dusting
properties of the final finished surface.
8. After Concrete initial setting, mechanical surface finishing operation by
power-floating & power toweling is started & continued until a leveled,
anti abrasive, non-dusting shiny concrete surface in achieved. A very special
care is carried out to the edges with guide rails angles, walls & columns.
9. After the final finishing, a resin-base curing compound is applied by roller
to the surface in order to insure hydration water not to be lost from the green
concrete. This is very important in assuring that the concrete compressive
strength is to be reached.
10. Within 24 --- 48 hrs, saw-cut contraction joints are to be formed by
special diamond blade taking into consideration the location of the old already
existing floor joints. New joint dimension is 3.00 --- 5.00mm wide which
insures good resistance for edges not to be damaged by any moving handling
equipment having wheels/tires according to specifications.
11. Joints are to be sealed by a trafficable appropriate joint sealant applied
after the insertion of a backer rod.
12. The new existing floor screed should not be used mechanically before 28
days unless the cubes crushed after 7 days may insure reaching the compressive
strength. In general, it is not recommended to use the floor even for
pedestrians before 7 days from casting. The same condition is to be taken into
consideration in case of fixations for the frames of the racking system.
13. A surface sealer/hardener of epoxy base could be used as an option in order
to increase the anti dust properties of the surface in order to insure the
surface being easily cleaned & maintained.
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