ACI CONCRETE FIELD TESTING TECHNICIANS GRADE 1 (IN CANADA) EXAM QUESTIONS AND ANSWERS

ACI CONCRETE FIELD TESTING TECHNICIANS GRADE 1 (IN CANADA) EXAM QUESTIONS AND ANSWERS The standard practice describes the _____ _____ and _____ required to obtain a representative sample of fresh concrete and to assess its tractability to the structure it represents. - Answer- procedures, location and sample size The procedures used in sampling shall include the use of every precaution that will assist in obtaining samples that are truly representative of the _____and _______ of the concrete. - Answer- nature, conditions Intermittent scooping of the sample in shovelfuls or bucketfuls into a wheelbarrow or tray as the concrete continues to flow down the delivery chute is an acceptable technique? - Answer- False The concrete sample must be protected at all times from sun, wind,____and - Answer- rapid evaporation, contaminants the minimum size sample for making strength test cylinder specimens is - Answer- 20l for 100x200mm 30l for 150x300mm 55l when 3 flexural beams are made When sampling for uniformity of mixed concrete____grab samples shall be obtained from widely separated portions of the batch during discharge - Answer- Three The sample form a mixer must be obtained between the ____% and ____%points of the discharge - Answer- 10, 90 When the concrete contains aggregate whose nominal size is larger than that permitted for a particular test method, the sample of concrete must be _____before making the test(except for Density tests) - Answer- Wet Sieved(over the appropriate sieve size) Air content (pressure method) measurement and slump must both be completed within___minutes of transporting and remixing of the sample - Answer- 10 Moulding of concrete strength cylinders must b e completed within____minutes after the sample has been transported and remied. - Answer- 20 What document produced by the concrete supplier contains information relating to identification of the concrete sample? - Answer- The delivery ticket Describe the operation of obtaining a sample for evaluation of concrete quality. - Answer- Obtain a single grab sample at one point of the discharge in as short a time as possible. Between what two points of the mixer discharge must the concrete be sampled? - Answer- the 10% and 90% points How is the sample obtained from the discharge stream of a mixer truck? - Answer- Pass the receptacle completely through discharge stream OR completely divert discharge stream into sample container. What is the minimu size of sample to be obtained when strength test specimens are to be moulded? - Answer- 20l when 100dia x 200mm cylinder are made 30l when 150dia x 300mm cylinders are made 55l when three flexural beams are to be made From what conditions must the concrete sample be protected? - Answer- Sun, wind, rapid evaporation and contamination