Aci concrete strength testing technician CP-19 23rd Ed.

Aci concrete strength testing technician CP-19 23rd Ed Questions And Answers These procedures for capping enable concrete cylinders and cores to meet the standard practices requirements for __________ and __________. - Planeness , perpendicularity Equipment needed for the capping process includes capping __________ , __________ devices and __________ pots. - Plates , alignment , melting. Plates for neat cement and high-strength gypsum plaster caps should be made of __________, __________, __________, or __________. - Glass, metal, granite, diabase Sulfur mortar cap plates should be formed against __________ or __________ plates. - Metal, stone The purpose of the guide bar or bullseye level is to ensure that caps remain perpendicular to the axis of the cylinder within 0.5 degrees. True or False? - True To avoid accidents during reheating of cooled sulfur, use melting pots that have __________. - Peripheral heating The technician should use a stiff layer of __________ to cap fresh concrete cylinders. - Neat cement paste Hardened concrete cylinders should be capped with __________, __________, or __________. - High-strength gypsum paste, neat cement paste, sulfur mortar Plaster of Paris and mixtures of plaster of Paris and Portland cement are examples of suitable high-strength plasters. True or False - False Sulfur mortars and high-strength gypsum cement cubes must demonstrate a minimum compressive strength of __________ or __________, whichever is greater. - 35 MPa [5000 psi], cylinder strength The cement paste should be applied to the freshly molded cylinder from __________ hours after molding. This is to allow for __________ of the concrete specimen - 2 to 4, settling The strength of the paste depends on: A. The water-cement ratio B. Time C. The equipment used D. Type of cement - A, B, and D The slight twisting action will help eliminate __________ and air __________ when the capping plate is placed into the mound of paste. - Excess paste, voids Neat cement paste caps should not be used on dry specimens because the caps may _____ and _____ when dry. - Shrink, crack The technician should remove all _____ or _____ materials from the ends of hardened concrete cylinders before capping. - oily, waxy _____ the pot and recharge with fresh material at intervals to ensure that the oldest material in the pot has not been used more than _____ times. - Empty , five When capping concrete cylinders with a compressive strength of 35 MPa [5000 psi] or greater, it is permitted to reuse compound recovered from the the capping operation of old caps. True or False - False To avoid _____, the sulfur mortar should be dry when it is added to the pot. It should be kept away from _____ when heating - Foaming, water The melting pot for the sulfur mortar must be located under a(n) __________ with a(n) __________ for __________. - Hood, exhaust fan, ventilation Hydrogen sulfide gas, which may be produced during capping, may be _____ in high concentrations. In lower concentrations, the gas may result in _____, _____, _____, _____, and _____. - Lethal , nausea, stomach distress, dizziness, headache, irritation of the eyes. When qualifications tests of unbonded pads are required, they are performed by the _____ or_____. - Supplier, user This standard practice establishes a maximum number of pad reuses that may not be exceeded under any circumstances. True or False - False Unbonded caps are not to be used for acceptance testing of concrete with compressive strength below _____ or above _____. - 10 MPa [1500psi], 80 MPa [12000 psi] Polyurethane or butyl pads with a shore A durometer hardness of 50 that will be used on concrete with a compressive strength of 10 to 40 MPa [1500 to 6000 psi] need not be qualified prior to use. True or False? - False To keep track of pad usage the user is required to maintain records that include _____, _____, and _____. - 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 10 and 40 MPa [1500 to 6000 psi], it may be used "as is" from the manufacturer without further qualification testing. True or False? - True The term "unbonded cap" refers to the combination of a metal retainer and an elastomeric pad. True or False? - True Practice C1231/C1231M may be used instead of the capping requirements of practice C617/C617M. True or False? - 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? - True When qualifying unbonded caps, strengths below __________ of the average obtained from bonded caps is considered unacceptable. - 98% Practice C1231/C1231M contains step-by-step procedures for aligning the specimens in the testing machine through complete failure of the cylinder. True or False? - False The pads used in this practice must be _________ thick, and the diameter shall not be more than _________ smaller than the inside diameter of the retaining ring. - 13 ± 2 mm [1/2 ± 1/16 in.], 2 mm [1/16 in.] The height of the metal retaining ring must be _____. - 25 ± 3 mm [1.0 ± 0.1 in] The inside diameter of the retaining rings shall not be less than _____ or greater than _____ of the diameter of the cylinder. - 102%, 107% Depressions in the ends of the cylinders that exceed _____ must be corrected by sawing or grinding prior to testing. - 5 mm [0.20 in] Qualification tests on an unbonded capping system must be repeated whenever there are changes in ________________________________________________________________________,________________________________________________________________________,or ____________________________________________________________________. - The design or dimensions of the retaining rings, pad composition or thickness, the shore A hardness by more than five units This test method measures the compressive strength of cylindrical concrete specimens that have a density of less than 800 kg/m³ [50 lb/ft'). True or False? - False; have a density of more than 800 kg/m³ [50 lb/ft'] Test Method C39/C39M consists of applying a compressive axial load to molded cylinders or cores at any rate until failure occurs. True or False? - False; a prescribed rate Results obtained from the compressive strength test method will depend on many things, such as the size and _____ of the specimen, batching, _____ procedures, the age, temperature, and _____conditions during curing. - Shape, mixing, moisture This test method is used to determine _____ of cylindrical specimens. - Compressive strength The calibration of the testing machines must be verified under four conditions: within _____ months of the last calibration, upon original installation or after _____, after making _____ or adjustments, and whenever there is reason to suspect the _____ of the indicated loads. - 13, relocation, repairs, accuracy The machine must be power operated and apply the load intermittently. True or False? - False; apply the load continuously Supplemental means of loading for calibration may be power or hand operated. True or False? - True The percentage of error for loads used in the testing machine should not exceed _____ of the indicated load. - ± 1.0% The testing machine should have two steel bearing blocks: a spherically seated block and a solid block. True or False? - True The _____ and _____of the spherically seated bearing block must be designed so the steel in the contact area doesn't permanently deform when loaded to the capacity of the testing machine. - Ball, socket The curved surface of the socket should be _____ and lubricated with _____ at least every _____ months. - Clean, petroleum-type oil, six Specimens should not be tested if any individual diameter of a cylinder differs from another diam- eter of the same cylinder by less than 2%. True or False? - Fals