CCIL certification

What are the dimensions of the slump cone?

300 mm high, 200 mm bottom diameter, 100 mm top diameter

How many layers is concrete placed in during a slump test?

3 layers

How many rod strokes are applied to each layer?

25 strokes

How far should the rod penetrate into the previous layer?

Approximately 25 mm

How long should the slump cone be lifted?

5 ± 2 seconds

How long may the slump test take after sampling?

Maximum 10 minutes

How long may filling and removal take?

Maximum 2 minutes

What is slump?

Difference between mould height and concrete height after subsidence

What should be done if the sample shears or collapses?

Repeat the test

How many slump tests are typically performed?

3 (low, mid, high)

What is the purpose of the slump test?

Determine workability/consistency of fresh concrete

What surface must the slump mould be placed on?

Flat, level, moist, rigid, non-absorbent surface

What information must be reported for a slump test?

Sample ID, date/time, slump value, technician, reviewer, deviations

Why are concrete cylinders made?

Quality control and evaluation of concrete strength

What factors affect concrete quality?

Batching, mixing, moulding, curing, handling

How is cylinder diameter measured?

Average of two measurements at right angles

Where is cylinder diameter measured?

At mid-height

How should cylinders be stored before testing?

Kept moist (moist curing conditions)

Why is proper curing important?

Ensures accurate and consistent concrete properties

What is the density formula?

Density = Mass ÷ Volume

What units is density reported in?

kg/m³