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2025 - 2026 ACI CONCRETE STRENGTH TESTING
TECHNICIAN CP-19 (14) EXAM|100 QUESTIONS AND
ANSWERS|A+GRADE
These procedures for capping enable concrete cylinders and cores to meet the standard's requirements for and ANS:->> Planeness, perpendicularity Equipment needed for the capping process includes capping , devices, and pots ANS:->> Plates, alignment, melting Plates for neat cement and high strength gypsum plaster caps should be made of , , or ANS:->> Glass, metal granite or diabase Sulfur mortar cap plates should be formed against or plates ANS:->> 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? ANS:->> True To avoid accidents during reheating of cooled sulfur, use melting pots that have ANS:->>Peripheral heating The technician should use a stiff layer of to cap fresh concrete cylinders
ANS:->> Neat cement paste Hardened concrete cylinders should be capped with , or ANS:->> 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? ANS:->> โโ - False Sulfur mortars and high-strength gypsum cement cubes must demonstrate a minimum compressive strength of or , whichever is greater ANS:->> 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 ANS:->> 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 e) ANS:->> โโ - a, b and d f) A slight twisting action will help eliminate and air when the capping plate is placed onto the mound of the paste ANS:->> Excess paste, voids
When qualification tests of unbonded pads are required, they are performed by the or ANS:->>Supplier, user This standard (ASTM 1231) established a maximum number of pad reuses that may not be exceeded under any circumstances. True or false? ANS:->> โโ- False Unbonded caps are not to be used for acceptance testing of concrete with compressive strength below or above ANS:->> 1500 psi (10 MPa), 12,000 psi (80 MPa) Polyurethane or butyl pads with a Shore A durometer hardness of 50 that will be used on concrete with a compressive strength of 1500 to 6000 psi (10 to 40 MPa) need not be qualified prior to use. True of False? ANS:->> โโ- False To keep track of pad usage, the user is required to maintain records that include. ANS:->> โโ- Date placed in service, pad durometer, number of uses if a new neoprene pad with a Shore A durometer hardness of 50 is intended to test concrete cylinders with anticipated compressive strengths between 1500 and 6000 psi (10 and 40 MPa), it may be used "as is" from the manufacturer without further qualification testing. True or False? ANS:->> โโ- True The term "unbonded cap" refers to the combination of a metal retainer and an elastomeric pad. True or False? ANS:->> โโ- True The practice of ASTM C1231 may be used instead of the capping requirements ASTM C617. True or False? ANS:->> โโ- True The pads provide a uniform distribution of load from the bearing blocks of the
testing machine by deforming in initial loading to conform to the contour of the ends of the cylinder. True or False? ANS:->> โโ- True When qualifying unbonded caps, strengths below % of the average obtained from bonded caps is considered unacceptableANS:->>98% The practice of ASTM C1231 contains step-by-step procedures for aligning the specimens in the testing machine through complete failure of the cylinder. True or False? ANS:->> โโ- False; only through initial application of the load The pads used in this practice (ASTM C1231) must be thick, and the diameter shall not be more than smaller than the inside diameter of the retaining ringANS:->>1/2 ยฑ 1/16 in., 1/16 in. The height of the metal retaining ring must be ANS:->>1.0 ยฑ 0.1 in. The inside diameter of the retaining rings shall not be less than or greater than of the diameter of the cylinderANS:->>102%, 107% Neither end of the cylinder shall depart from perpendicularity by more than ANS:->>0. degrees Depressions in the ends of the cylinders that exceed must be corrected by sawing or grinding prior to testingANS:->>.20 in. Pads that have cracks or splits exceeding in regardless of their must be replacedANS:->>3/8 in., length, depth Rotation of the movable portion of the testing machine's spherically seated
The machine must be power operated and apply the load intermittently. True or False? ANS:->> โโ- False, apply the load continuously Supplemental means of loading for calibration may be power or hand operated. True or False? ANS:->> โโ- True The percentage of error for loads used in the testing machine should not exceed of the indicated loadANS:->>ยฑ 1.0%
The testing machine should have two steel bearing blocks; a spherically seated block and a solid block. True or False? ANS:->> โโ- True The and of the spherically seat bearing block must be designed so the steel in the contact area doesn't permanently deform when loaded to the capacity of the testing machineANS:->>Ball, socket The curved surface of the socket should be and lubricated with at least every monthsANS:->>Clean, petroleum-type oil, six (or as specified by the manufacturer of the test machine) The block should provide a readily machinable surface for maintenance of the specified surface conditionsANS:->>Bottom bearing Specimens should not be tested if any individual diameter of a cylinder differs from another diameter of the same cylinder by less than 2%. True or False? ANS:->> โ โ- False, by more than 2% If cylinders have been made from a single lot of molds which consistently produce nearly the same sized specimens, the number of individual cylinders measured is not prohibited from being to one for each ten specimens or per day whichever is greaterANS:->>Reduced, Three When conducting compression tests of moist-cured specimens, wait at least three days after their removal from moist storage before testing. True or False? ANS:-
โโ- False, test shall be made as soon as practicable Test specimens should be during the period between storage and testingANS:->>Kept moist When placing the lower bearing block on the table or platen, place the upANS:-
The results of this test method may be used to determine quality control of concrete proportioning, mixing, and operations; compliance with , or for evaluating the effectiveness of ANS:->>Placing, specifications, admixtures The load of a compression machine can be registered on a or in ANS:-
Dial, digital form Hand operated machines have pumps that do not provide a continuous loading in one stroke are not permitted. True or False? ANS:->> โโ- True Bearing blocks used in the method must ensure that forces applied to the beam will be perpendicular to the face of the specimen and applied without eccentricityANS:->>Third-point loading The testing equipment must be capable of maintaining distances between load- applying and support blocks constant within inchesANS:->>ยฑ 0.05 inches Which of the following requirements for load-bearing and support blocks: a) They should be 2.50 inches high or less b) They should be half as wide as the specimen c) They should be in contact with the rod or ball ANS:->> โโ- a) and c) Test specimen surfaces should be smooth and free of , , or ANS:- Scars, indentations, holes, inscribed identification marks In relation to the applied force, the loading system should be centered during the procedure. True or False? ANS:->> โโ- True During the testing, if suitable contact is not made between the specimen and bearing block surfaces, , or may be requiredANS:->>Use of shims, grinding, capping
It is acceptable to use leather shims only when the gap between the specimen in contact with the blocks is not 0. inchesANS:->>Surface, more than To determine the the average width, depth and line of fracture location of the specimen, you should take measurements across each ANS:->>Three, dimension Discard the test results when the fracture occurs in which of these instances: a) outside the middle third of the span length but by less than 5% of the span length. b) c) outside the middle third of the span length by more the 5% of the span length d) within the middle third of the span length ANS:->> โโ- b) If a fracture occurs at a capped section, you should not include the thickness of the cap in your calculations. True or False? ANS:->> โโ- False, include cap thickness The formula, R = PL/bdยฒ, measures the modulus of rupture at which location? ANS:->> โโ- In the tension surface within the middle third of the span length The final report should include both the average width and depth to the nearest inch. ANS:->> โโ- 0.05 inch The report must also include information about the length , the applied load and the of ruptureANS:->>Span, maximum, modulus
