Field Testing Technician Flashcards

Per ASTM C172, composite concrete samples shall NOT be taken from the first or last:

Answer: 10% of the load

ASTM C172 requires that the first and last 10% of each load be excluded from sampling because these portions may not represent the bulk of the concrete.

A composite sample per ASTM C172 must be composed of not fewer than:

Answer: 2 portions taken from different points in the load discharge

ASTM C172 requires composite samples to consist of not fewer than two portions collected from different points during the load discharge.

When a field test reveals that concrete slump exceeds the specification limit, the ACI field testing technician's primary responsibility is to:

Answer: Perform and document all required tests, then notify the responsible party

The technician's role is to test and accurately document results; acceptance or rejection decisions belong to the engineer of record, not the testing technician.

Which ASTM standard is the practice for making and curing concrete test specimens in the field?

Answer: ASTM C31

ASTM C31 is the standard practice for making and curing concrete test specimens in the field; C192 covers laboratory fabrication.

Which ASTM standard covers the procedure for sampling freshly mixed hydraulic cement concrete?

Answer: ASTM C172

ASTM C172 is the standard practice for sampling freshly mixed concrete and is the first step before any other fresh concrete testing.

Per ASTM C1064, the minimum immersion depth for a concrete temperature-measuring device is:

Answer: 3 inches (75 mm)

ASTM C1064 requires the temperature device to be inserted to a minimum depth of 3 inches (75 mm) to ensure an accurate reading.

The initial curing period under ASTM C31, during which standard-cured specimens are protected at the job site before transport, lasts:

Answer: 24 hours after molding

Initial curing under ASTM C31 covers the first 24 hours after molding, during which specimens must be protected from temperature extremes and drying.