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11:26 PM
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RULE 6
CONCRETE DELIVERY
Before the first concrete load is delivered to the jobsite,
RULE 5
REINFORCING
coordination efforts should have already been performed
between the owner’s authorized representative, the design-
Without the use of slab reinforcement, concrete may not be struc-
er/architect, concrete contractor, and general contractor.
turally strong enough to support heavy loads or prevent slab dis-
Topics should include mix design, finish elevations, utility
placement from settling or if expansive conditions should occur.
coordination, concrete pour sequencing and scheduling,
The types of slab reinforcement commonly used are:
joint layout and finish type. When the first load of concrete
is delivered, the following steps should be followed:
1. Synthetic fibers, used as an admixture when concrete is
mixed. Can be used with, and is recommended as an addition to, rebar.
2. Electrically Welded Wire Mesh (E.W.W.M.), not recommended
for architectural concrete due to the lack of sheer value.
3. Reinforcing steel (rebar), the most common size and spacing
for normal pedestrian and vehicular architectural concrete is
at the very minimum #3 bar at 18-inch o.c.e.w. to maximum
#5 bar at 12-inch o.c.e.w. Shaw & Sons recommends #4 bar
at 18-inch o.c.e.w.
4. Steel Dowels, used to connect adjacent pour slabs at construction joints. Always use the Speed Dowel system (match
rebar size and on-center spacing, e.g. for #4 rebar at 18-inch
on-center, use #4 Speed Dowel 18-inch on-center). Speed
Dowel is a plastic sleeve system that requires an 18-inch
long to 2-foot long smooth steel dowel (see the Shaw expansion construction joint, page 152).
5. Rebar numbers indicate the approximate diameter of rebar
in 1/8-inch increments. Example #3 rebar is 3/8-inch in
approx. diameter; #4 rebar is 1/2-inch in approx. diameter;
# 5 rebar is 5/8-inch in approx. diameter.
6. For topping slabs in extremely thin conditions, use 1/4-inch
stainless steel dowels.
1. Verify the load delivered matches the certified Statement of
Mix Design for that particular paving finish. Carefully
review delivery ticket to ensure correct mix.
2. Verify that slump is within the stated range; typically 4-inch
to 5- inch slumps within a +/- 1-inch tolerance (slump test
should be taken at point of discharge; at the end of the hose
if pumped.)
3. Overall weather and ambient temperature, material conditions, and truck travel time can affect the slump. (Note:
Projects close to batch plants require more on-site mixing
time for concrete than concrete brought from plants further
away.)
4. Accepting concrete that falls outside the specified slump
may result in weakened concrete and visual variations in
adjacent pours (Shaw & Sons would reject this concrete).
5. One gallon of water for each cubic yard of concrete added
at the time of pour to increase slump loses approx. 200 PSI
to the concrete’s strength and will gain approx. 1 inch in
slump (never exceed maximum design).
6. Each delivered load should be mixed at the job site a minimum
of 100 revolutions, and must be checked visually prior to dispensing the first yard of each load to ensure a proper mix.
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