CCIL Concrete Compressive Strength Testing 5

Question 1

Which standard governs the use of unbonded neoprene pad caps for compression testing of concrete cylinders?

Accepted Answer

ASTM C1231

Answer

ASTM C1231 covers unbonded neoprene pad capping systems as an alternative to the bonded capping methods in ASTM C617.

Question 2

A technician discovers that a concrete cylinder was stored at 35°C (95°F) for the first 48 hours after casting. What is the most likely impact on 28-day strength?

Accepted Answer

Lower 28-day strength due to disruption of normal hydration reactions

Answer

Excessive early curing temperatures accelerate early strength gain but disrupt normal hydration, resulting in lower long-term (28-day) strength.

Question 3

What is the minimum capacity verification frequency required for compression testing machines used in accredited laboratories per CCIL requirements?

Accepted Answer

Every 6 months or after any repairs

Answer

CCIL and ASTM E4 require verification of compression machine accuracy at least every 12 months, but CCIL accreditation often mandates verification every 6 months or after repairs.

Question 4

What minimum concrete compressive strength range is required before neoprene pad caps per ASTM C1231 are considered acceptable for use?

Accepted Answer

Greater than 10 MPa (1,450 psi)

Answer

ASTM C1231 specifies that unbonded neoprene pads are appropriate for concrete with compressive strengths between 10 MPa and 50 MPa (1,450 to 7,250 psi).

Question 5

When must a fresh concrete cylinder be moved to standard moist curing after initial field curing per ASTM C31?

Accepted Answer

Within 24 hours of casting

Answer

ASTM C31 requires cylinders to be transported to the standard curing environment within 48 hours, but they must not be moved during the first 24 hours to avoid early-age disturbance.

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL Concrete Compressive Strength Testing 5