Curing, Protection & Quality Control Flashcards

What is the minimum curing period recommended by ACI 308 for concrete made with Type I/II cement under normal temperature conditions?

Answer: 7 days

ACI 308 recommends a minimum of 7 days of curing for concrete made with Type I/II cement at normal temperatures.

Which curing compound application method ensures the most uniform coverage on a freshly finished slab?

Answer: Spray application in two passes at right angles

Spraying curing compound in two perpendicular passes ensures overlapping, uniform coverage with no missed areas.

Hot weather concrete placement is generally considered to occur when ambient temperature exceeds what threshold?

Answer: 90°F (32°C)

ACI 305 defines hot weather concreting conditions as those where ambient temperature exceeds 90°F (32°C).

A slump test result that is 2 inches higher than specified most likely indicates which quality control problem?

Answer: Excess water added at the jobsite

Excess slump beyond specification is the classic indicator of unauthorized water addition, which increases w/c ratio and reduces strength.

Which type of curing blanket is most appropriate for protecting concrete from freezing temperatures?

Answer: Insulating blankets with foam core

Insulating blankets with foam cores provide both moisture retention and thermal protection needed to prevent freezing.

What does a low rebound hammer reading relative to the specified concrete strength indicate?

Answer: The concrete may not have reached design strength

A rebound hammer measures surface hardness; a low reading suggests the concrete may be weaker than the design strength.

When should white-pigmented curing compound NOT be used?

Answer: On surfaces that will receive a bonded overlay or coating

Curing compounds form a membrane that prevents bond between concrete and subsequent overlays, adhesives, or coatings.