ASTM ACI Concrete Strength Testing Lab Technician, Questions and Correct Answers, With Complete Solution.

ASTM ACI Concrete Strength Testing Lab Technician, Questions and Correct Answers, With Complete Solution. C617 ASTM Standard dealing with proper capping methods Planeness and Perpendicularity The procedure for capping enables concrete cylinders to meet the standard's requirements for ____ and ____ plates, alignment, melting equipment needed for the capping process include ____, ____ devices, and ____ pots glass, metal, granite, diabase Plates for neat cement and high-strength gypsum plaster caps should be made of ____, ____, ____, or ____ metal or stone Sulfur mortar cap plates should be formed against _____ or _____ .5 The purpose of the guide bar or bullseye level is that caps remain perpendicular to the axis of the cylinder within _____ degrees peripheral heating to avoid accidents during reheating, use melting pots that have _____ _____ Neat Cement Paste The technician should use a stiff layer of _____ to cap fresh concrete cylinders. high strength gypsum paste, neat cement paste or sulfur mortar Hardened concrete cylinders should be capped with _____ _____ _____ _____, _____ _____ _____, or _____ _____. False- They are not suitable Plaster of Paris and Portland Cement are examples of suitable high-strength plasters. True or False? 5000 psi or 35 MPa or the cylinder's strength Sulfur mortars and high strength gypsum cement cubes must demonstrate a minimum compressive strength of _____ or _____; whichever is greater. 2 to 4, setting The cement paste should be applied to the freshly molded cylinders from _____ to ______ hours after molding. This is to allow ______ of the concrete specimen. a, b, d The strength of the cement paste depends on: Choose all that apply: a) water-cement ratio b) time c) equipment used d) type of cement excess paste, voids A slight twisting motion will help eliminate _____ and air _____ when the capping plate is placed onto the mound of paste. shrink, crack Neat cement paste caps should not be used on dry specimens because the caps may _____ and _____ when dry. oily, waxing The technician should remove all _____ or _____ materials from the ends of hardened concrete cylinders before capping Empty, 5 _____ 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. False When capping concrete cylinders with a compressive strength of 5000 psi (35 MPa) or greater it is permitted to reuse compound recovered from the capping operation of old caps. True or false? foaming, water To avoid _____, the sulfur mortar should be dry when it is added to the pot. It should be kept away from _____ when heating. hood and exhaust for venting The melting pot for the sulfur mortar must have a _____ and _____ for _____ deadly. nausea, stomach distress, dizziness, headache, eye irritation Hydrogen Sulfide gas, which may be produced during capping, may be _____ in high concentrations. In lower concentrations, the gas may result in: (5 answers) Unbonded caps ASTM C1231 deals with the practice of using ______ _____ supplier, user When qualification tests of unbounded pads are required, they are performed by the ______ or ______ False ASTM C1231 establishes a maximum number of pad reuses that may not be exceeded under any circumstances. True of false? 1500 psi (10 MPa) - 12000 psi (80 MPa) Unbonded caps are not to be used for acceptance testing of concrete with compressive strength below _____ or above _____. False 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 need not be qualified prior to use. True or False? Date the pads were placed in service, the pad durometer, and number of uses To keep track of pad usage, the user is required to maintain records that include: True If a new neoprene pad with a Shore A durometer hardness of 50 is intended to test concrete cylinders with an anticipated compressive strength between 1500 and 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 ASTM C1231 may be used instead of the capping requirements of ASTM 617. True or False? True The pads provide a uniform distribution of load from the bearing blocks of the testing amchine by deforming in initial loading to conform to the contour of the ends of the cylinder. True or false? 98 When qualifying unbonded caps, strengths below _____ % of the average obtained from bonded caps is considered unacceptable False ASTM C1231 contains step by step procedures for aligning the specimens in the testing machine through complete failure of the cylinder. True or false? 3 +- 2mm (1/2" +- 1/16"), 2mm (1/16") The pads used in this practice must be _____ thick, and the the diameter shall not be more than _____ smaller than the inside diameter of the retaining ring. 25 +- 3mm (1 in +- .1 in) The height of the metal retaining ring must be ______. 102 %, 107 % The inside diameter of the retaining rings shall not be less than ______ or greater than _______ of the diameter of the cylinder .5 degrees Neither end of the cylinder shall depart from perpendicularity by more than ________ degrees 5mm (.2 in) Depressions in the ends of cylinders that exceed _______ must be corrected by sawing or grinding prior to testing. 3/8 in (10mm), length, depth pads that have cracks or splits exceeding ______ in _____ regardless of their _______ must be replaced False Rotation of the movable portion of the testing machine's spherically seated bearing block as it is brought to bear on the upper retaining ring is not necessary when using pad caps, since the pad's deformation will compensate and provide uniform loading. True or false? the design or dimensions of the retaining rings, pad composition or thickness, or the shore A hardness by more than 5 units qualification tests on an unbonded capping system must be repeated whenever there are changes in: (3 answers) 50 %, 1/8 in 12 After application of the load, but before ______ of the anticipated specimen strength, check to see that the axis of the cylinder is vertical within a tolerance of _______. C39 ASTM standard dealing with compressive strength of cylindrical concrete specimens