ACI Concrete Strength Testing
Technician CP-19 (14)-Graded A
These procedures for capping enable concrete cylinders and cores to meet the
standard's requirements for ________ and _________. - ANSWER-Planeness,
perpendicularity
Equipment needed for the capping process includes capping _____ , _____devices,
and ______ pots. - ANSWER-Plates, alignment, melting
Plates for neat cement and high strength gypsum plaster caps should be made of
_____, _____, _____ or _____. - ANSWER-Glass, metal granite or diabase
Sulfur mortar cap plates should be formed against _____ or _____ plates. - ANSWER-
Metal, Stone
The purpose of the guide bar or bull's eye level is to ensure that caps remain
perpendicular to the axis of the cylinder within 0.5 degrees. True or False? - ANSWER-
True
To avoid accidents during reheating of cooled sulfur, use melting pots that have _____.
- ANSWER-Peripheral heating
The technician should use a stiff layer of _____ to cap fresh concrete cylinders. -
ANSWER-Neat cement paste
Hardened concrete cylinders should be capped with _____, _____ or _____. -
ANSWER-High-strength gypsum paste, neat cement paste, or sulfur mortar
Plaster of paris and mixtures of plaster of paris and portland cement are examples of
suitable high strength plasters. True or False? - ANSWER-False
Sulfur mortars and high-strength gypsum cement cubes must demonstrate a minimum
compressive strength of _____ or ___ __, whichever is greater. - ANSWER-35MPa
(5000 psi), the cylinder strength
The cement paste should be applied to the freshly molded cylinder from _____ to _____
hours after molding. This is to allow for _____ of the concrete specimen. - ANSWER-
2,4, settling
The strength of the paste depends on:
, a) the water-cement ratio
b) time
c) the equipment used
d) type of cement - ANSWER-a, b and d
A slight twisting action will help eliminate _____ and air _____ when the capping plate is
placed onto the mound of the paste. - ANSWER-Excess paste, voids
Neat cement paste caps should not be used on dry specimens because the caps may
_____ and _____ when dry. - ANSWER-Shrink, crack
The technician should remove all _____ or _____ materials from the ends of hardened
concrete cylinders before capping - ANSWER-Oily, waxy
_____ the pot and recharge with fresh material at intervals to insure that the oldest
material in the pot has not been used more than _____ times. - ANSWER-Empty, 5
When capping concrete cylinders with a compressive strength of 35 MPa (5000 psi) or
greater, it is permitted to reuse compound recovered from the capping operation of old
caps. True or False? - ANSWER-False
To avoid _____, the sulfur mortar should be dry when it is added to the pot. It should be
kept away from _____ when heating. - ANSWER-Foaming, water
The melting pot for the sulfur mortar must be located under a _____ with an _____ for
_____. - ANSWER-Hood, exhaust fan, ventillation
Hydrogen sulfide gas, which may be produced during capping, may be _____, _____,
_____, _____ and _____. - ANSWER-Lethal, nausea, stomach distress, dizziness,
headache, irritation of the eyes.
After application of the load, but before reaching _____ of the anticipated specimen
strength, check to see that the axis of the cylinder does not depart from vertical by more
than _____. - ANSWER-10%, 0.5 degrees
Qualification tests on an unbonded capping system must be repeated when ever there
are changes in _____. - ANSWER-The design or dimensions of the retaining rings, pad
composition or thickness, or the Shore A hardness by more than 5 units
This test (ASTM C39) measures the compressive strength of cylindrical concrete
specimens that have a density of less than 50 lb/ft. True or False? - ANSWER-False;
have a density of more than 50 lb/ft.
Technician CP-19 (14)-Graded A
These procedures for capping enable concrete cylinders and cores to meet the
standard's requirements for ________ and _________. - ANSWER-Planeness,
perpendicularity
Equipment needed for the capping process includes capping _____ , _____devices,
and ______ pots. - ANSWER-Plates, alignment, melting
Plates for neat cement and high strength gypsum plaster caps should be made of
_____, _____, _____ or _____. - ANSWER-Glass, metal granite or diabase
Sulfur mortar cap plates should be formed against _____ or _____ plates. - ANSWER-
Metal, Stone
The purpose of the guide bar or bull's eye level is to ensure that caps remain
perpendicular to the axis of the cylinder within 0.5 degrees. True or False? - ANSWER-
True
To avoid accidents during reheating of cooled sulfur, use melting pots that have _____.
- ANSWER-Peripheral heating
The technician should use a stiff layer of _____ to cap fresh concrete cylinders. -
ANSWER-Neat cement paste
Hardened concrete cylinders should be capped with _____, _____ or _____. -
ANSWER-High-strength gypsum paste, neat cement paste, or sulfur mortar
Plaster of paris and mixtures of plaster of paris and portland cement are examples of
suitable high strength plasters. True or False? - ANSWER-False
Sulfur mortars and high-strength gypsum cement cubes must demonstrate a minimum
compressive strength of _____ or ___ __, whichever is greater. - ANSWER-35MPa
(5000 psi), the cylinder strength
The cement paste should be applied to the freshly molded cylinder from _____ to _____
hours after molding. This is to allow for _____ of the concrete specimen. - ANSWER-
2,4, settling
The strength of the paste depends on:
, a) the water-cement ratio
b) time
c) the equipment used
d) type of cement - ANSWER-a, b and d
A slight twisting action will help eliminate _____ and air _____ when the capping plate is
placed onto the mound of the paste. - ANSWER-Excess paste, voids
Neat cement paste caps should not be used on dry specimens because the caps may
_____ and _____ when dry. - ANSWER-Shrink, crack
The technician should remove all _____ or _____ materials from the ends of hardened
concrete cylinders before capping - ANSWER-Oily, waxy
_____ the pot and recharge with fresh material at intervals to insure that the oldest
material in the pot has not been used more than _____ times. - ANSWER-Empty, 5
When capping concrete cylinders with a compressive strength of 35 MPa (5000 psi) or
greater, it is permitted to reuse compound recovered from the capping operation of old
caps. True or False? - ANSWER-False
To avoid _____, the sulfur mortar should be dry when it is added to the pot. It should be
kept away from _____ when heating. - ANSWER-Foaming, water
The melting pot for the sulfur mortar must be located under a _____ with an _____ for
_____. - ANSWER-Hood, exhaust fan, ventillation
Hydrogen sulfide gas, which may be produced during capping, may be _____, _____,
_____, _____ and _____. - ANSWER-Lethal, nausea, stomach distress, dizziness,
headache, irritation of the eyes.
After application of the load, but before reaching _____ of the anticipated specimen
strength, check to see that the axis of the cylinder does not depart from vertical by more
than _____. - ANSWER-10%, 0.5 degrees
Qualification tests on an unbonded capping system must be repeated when ever there
are changes in _____. - ANSWER-The design or dimensions of the retaining rings, pad
composition or thickness, or the Shore A hardness by more than 5 units
This test (ASTM C39) measures the compressive strength of cylindrical concrete
specimens that have a density of less than 50 lb/ft. True or False? - ANSWER-False;
have a density of more than 50 lb/ft.
