CAUTION:
The bleeding tests should be run in a well-ventilated
room. Take care to avoid spilling carbon tetrachloride and breathing
the vapors. Keep the exposed portion of the liquid surface around
the funnel covered during the test.
4.3 VIBRATION:
Place the bleeding apparatus in a draft-free location and set it on
a sponge rubber mat or equivalent that will serve as a vibration
damper.
4.4 Notes:
Approximately 500 ml of carbon tetrachloride are required per test.
This may be reclaimed by siphoning off the liquid at the end of the
test and placing it in a separating funnel. The carbon tetrachloride
may be tinted with an oil-soluble dye for ease in reading the level in
the burette.
4.5 MORTARS
Immediately following the flow test, remix the mortar remaining in
the mixing bowl for 30 seconds. Within a total elapsed time of not
more than 2-1/2 minutes after completion of the original mixing of
the mortar batch, begin placing the mortar in the sample container.
Place the mortar in three layers, tamp each layer 40 times with the
tamper and strike off the surface level with the edge of the 5"
diameter container by screeding with a steel straight edge. Con-
duct the remainder of the test for the paste using as a start time the
completion of striking-off the surface of the mortar in the container.
5. Calculation
5.1 Calculate the initial rate of bleeding as follows, using values
taken during the first 30 minutes of the test when the bleeding
should be proceeding at a uniform rate:
Bleeding rate, cu cm per sq cm per sec = V1/At
Where,
V1 = Volume of bleeding water in cubic centimeters, measured
during time interval t
A = Area in square centimeters covered by the collecting ring, and
t = time in seconds during which bleeding occurs at a uniform rate.
