Field testing numbers

What is the first step before beginning field tests on a concrete sample?

Remix the concrete sample.

What portion of the discharge should be sampled?

Between 10% and 90% of the discharge.

How should a concrete sample be protected before testing?

From evaporation and contamination.

How much concrete must surround a thermometer?

Minimum 75 mm in all directions.

When must concrete temperature be measured?

Within 1–5 minutes of sampling or until stable for 30 seconds.

Where must concrete temperature be recorded?

On the concrete report.

What condition should all testing equipment be in before use?

Moistened.

How should testing equipment be positioned?

Level and free from vibration.

How should concrete be placed in the slump cone?

Evenly.

How should the layers be proportioned?

Approximately equal volume.

How far must the rod penetrate into the previous layer?

Approximately 25 mm.

How should rodding be performed?

Uniformly using an inclined and spiral pattern.

What is the maximum vibrator size permitted?

40 mm.

How are voids closed after each layer?

Using a mallet or open palm on single-use moulds.

How should the slump cone be held?

Firmly.

What should never be done on the slump board?

Stand on it during or after cone removal.

How much overfill is acceptable before strike-off?

Approximately 3 mm.

What must be cleaned before lifting the cone?

Around the base of the slump cone.

How should the cone be removed?

Lift vertically.

How long should cone removal take?

Approximately 5 seconds for the full height.

What motion is prohibited during cone removal?

Lateral or torsional movement.

How is slump measured?

Using the average height of the top surface.

What instructions must be followed when using an air meter?

Manufacturer's instructions.

How should the top of a cylinder be finished?

Smooth and level with minimal manipulation.

Maximum surface deviation for cylinders under 35 MPa?

Less than 3 mm.

Maximum surface deviation for cylinders over 35 MPa?

Less than 1 mm.

How should cylinders be protected after casting?

Prevent moisture loss.

What temperature range is required for cylinder storage?

15–25°C.

What environmental conditions must cylinders be protected from?

Direct sunlight and cold water.

Maximum time allowed to complete slump testing?

2 minutes.

Maximum time allowed to complete slump and air testing?

10 minutes.

Maximum time allowed to complete cylinder preparation?

20 minutes.

Does cylinder preparation time include remixing?

Yes.