Curing, Protection & Quality Control Flashcards

What is the purpose of using a maturity meter during concrete curing?

Answer: To estimate in-place concrete strength based on temperature-time history

The maturity method uses recorded temperature-time data to estimate the in-place strength development of concrete in real time.

Under ACI 308, ponding is considered which category of curing method?

Answer: Moist curing

Ponding maintains water directly on the concrete surface and is classified as a moist curing method per ACI 308.

Which condition would MOST likely cause map cracking (crazing) on a concrete flatwork surface?

Answer: Premature finishing of bleed water into the surface

Working bleed water back into the surface enriches the top layer with water, creating a weak, high-w/c skin prone to map cracking.

What is the standard ASTM test method for making and curing concrete compression test specimens in the field?

Answer: ASTM C31

ASTM C31 covers the standard practice for making and curing concrete test specimens in the field.

When placing concrete in freezing weather, which measure helps protect the concrete from freeze-thaw damage before adequate strength is gained?

Answer: Using Type III high-early-strength cement and enclosures with heat

Type III cement accelerates early strength gain and heated enclosures maintain temperature, both protecting concrete before it reaches freeze-thaw resistance.

Which curing method is most effective for vertical concrete surfaces such as walls and columns?

Answer: Membrane-forming curing compound applied by spray

Spray-applied curing compound is the most practical and effective method for curing vertical surfaces where ponding or blankets are difficult to maintain.

The maximum concrete temperature at the point of discharge allowed by most specifications in hot weather is:

Answer: 90°F (32°C)

ACI 305 recommends that concrete temperature at point of discharge not exceed 90°F (32°C) to control set time and strength.