Guaranteed Pass Solutions 2025.
Sampling from a mixer/truck agitator- Where is sample taken? - Answer Between 10% and
90% (Not when testing with Super P)
How is a sample taken when sampling plastic concrete? - Answer Either pass a receptacle
completely through a discharge stream OR divert a discharge stream completely into a sampling
container.
How many grab samples are needed when testing for uniformity of samples? - Answer 3
What size sample is needed when casting 3 100mm x 200mm cylinders? - Answer Minimum
20L
What size sample is needed when casting 150mm x 300mm cylinders? - Answer Minimum 30L
What size sample is needed when casting 150mm x 150mm x 535mm beams? - Answer
Minimum 55L
How much extra sample is needed when more than 3 cylinders/specimens are to be cast? -
Answer Volume of the cylinders/specimens plus 10% extra
How much time is allowed for obtaining, transporting and remixing the sample? - Answer 10
minutes
If A sample contains aggregate larger than that appropriate for the size of the moulds or
equipment. - Answer It must be wet-sieved prior to testing
Information required on reports - Answer Conc mix no, Sample source, Batch time/date,
Sample time/date, Project site, Sample location if different, Location of conc in structure,
Technician name, Lab name/address, Signature of test report reviewer, Any deviation from test
procedures
, What is Slump - Answer A measure of consistency of freshly mixed hydraulic cement concrete,
equal to the subsidence, measured to the next 5mm, of the moulded substance immediately
after the removal of the slump cone
Slump Flow - Answer The horizontal spread of concrete immediately upon removal of the
slump cone as a measure of the unconfined fluidity of concrete giving a relative degree of
indication of the degree to which concrete can travel
How many water-to-cementing materials ratios are needed for concrete trial mixes? - Answer
3
What temperature is considered stable before mixing concrete? - Answer 23 C +/- 2 C
Where should cementing materials be stored? - Answer In a dry place, in moisture-proof
containers
How much time is spent mixing concrete? - Answer Mix 3 minutes, rest 3 minutes, mix 2
minutes
Which sample can be re-used for casting cylinders? - Answer Slump or slump flow, NOT air.
Must be remixed into batch first
Cylinder mould material requirements - Answer Must have nonabsorbent surfaces and be
sufficiently rigid- Must be coated with mineral oil
Cardboard moulds cannot be used for what strength? - Answer Greater than 35MPa
Flexural mould requirements - Answer Must be rectangular and 50mm longer than the
prescribed span. Must be watertight and rigid, nonabsorbent. Variation from specified cross-
section is not to exceed 3mm. Coat with mineral oil.
Tamping Rod for 100mm x 200mm cylinders - Answer Diameter 10mm +/- 1mm and a Length
of 450mm to 600mm. One end must be hemispherical.
Tamping Rod for cylinders 150mm or greater, and rectangular moulds - Answer Diameter