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Water Retaining Concrete

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Rajendran

First I want to say thanks for the help. Second you must not sleep, much
5:00 AM ? The answers to your questions follows.

1.) Cracks are in the vertical direction.
2.) Some of the control joints cracked however there were also cracks 6"
away from the control joints through the tie holes. There were on the
average two additional cracks between the control joints which were at 25
ft. O/C.
3.) We only measured the cracks at the surfaces. The cracks were about the
same on both sides.
4.) The first wall was cured very badly. The forms were striped after one
day and vinyl backed burlap hung over the wall. The wall was not kept wet.
There were many times the inspector, other engineers and my self found the
burlap dry. The burlap was remover after seven days. This wall will be water
proofed with a membrane type water proofing material. The first wall was
placed in the second week of Aug. with the very high temps. The second wall
was cured according to specifications. The forms were loosened on the next
day and left in place for four days with a soaker hose on the top of the
wall to keep the forms wet. On the fourth day the forms were striped and
good vinyl backed burlap sheets were hung with a automatic sprinkler setup
for keeping the wall wet. The contractor was cooperative on the second wall
as we will bill him for the rework on the first wall. The cracks in the
second wall were not as sever as the first however there were two to three
thin cracks in each segment of the wall which runs about 20 ft. then made a
45 deg. turn. There are four of these dog legs in the second wall. No
control joints were used in the second wall because of the dog legs.
5.) No backfill was place before the cracks were found.
6.) No tests were done on the concrete after the wall was poured.
7.) We used water-reducing admixtures as recommended in ACI 650 sect. 3.2.
The water-reducing admixture and flyash were added to increase the density
of the concrete.
8.) We did use a Air Entrainment admix also. The test at the time of pouring
were about 4%.
9.) The second wall was a battened wall two ft. at the bottom and one ft. at
the top. The cracks were at the bottom and died out as they went to the top
on the second wall. Rebar was the same as the first wall.

If you or other members of the list want we can continue this off the
server. My E-Mail address is Acie_Chance(--nospam--at)wdi.disney.com

Thanks
Acie Chance