Humboldt H-4133 Acme Penetrometer - Manual (Page 3)

Introduction
Hydraulic reaction-type apparatus for determining the setting time of concrete with
slump greater than zero by testing mortar sieved from the concrete mixture. It also
determines the effects of variables such as temperature, cement, mixture proportions,
additions and admixtures upon the time of setting and hardening of concrete.
The penetrometer’s design makes it easy to operate, being more efficient, with a
longer gear rack. All needles are one length so settings may remain the same.
Loads are applied hydraulically with pressures read on a 200 lbf (890N) capacity
gauge graduated in 2 lbf divisions. Set of six needles allows multiplication to a maximum
reading of 8000 lbf. The Acme penetrometer features cast aluminum base and set of
stainless steel penetration needles in a wooden block (bearing area: 1, 1/2, 1/4, 1/10,
1/20 and 1/40 sq. in., (645, 323, 161, 65, 32 and 16mm
2 ). Includes 100 laboratory test
data reporting forms. Meets ASTM C403; AASHTO T197. Shipping wt. 60 lbs. (27kg)
Preparation of Mortar Specimens
From the concrete mixture under test, select a representative sample of concrete
of sufficient volume to provide enough mortar to fill the test container(s) to a
depth of at least 5-1/2 inches (140 mm).
Remove essentially all of the mortar from the sample of concrete by sieving it
through a No. 4 (4.75 mm) sieve onto a non-absorptive surface.
Thoroughly remix the mortar by hand method on the non-absorptive surface and
place it in the container(s) and compact by rodding. Rod the specimen by means
of the tamping rod held so as to penetrate the mortar with the round end. Rod the
mortar once for each 1 in
2 (6.5 cm 2 ) of top surface area of the specimen and
distribute the strokes uniformly over the cross section of the specimen. After
completion of the rodding, tap the sides of the containers lightly with the tamping
rod to close voids left by the tamping rod and to further level the surface of the
specimen. Upon completion of specimen preparation, the mortar surface shall be
1/2 inch (13 mm) below the top edge of the container to provide space for the
collection and removal of bleeding water and to avoid contact between the
mortar surface and the protective covering such as damp burlap or a tight fitting
water impermeable cover.
Storage of Mortar Specimen
Store and maintain the specimens at the desired temperature of test. To prevent
excessive evaporation of moisture, keep the specimens covered with a suitable material
such as damp burlap or a tight fitting, water impermeable cover for the duration of the
test, except when bleeding water is being removed or penetration tests are being made.
The specimens shall be shielded from the sun.