Practice Test Geeks(ACI) American Concrete Institute Concrete Finisher Practice Test
← All ACI Flashcard Decks

Cold & Hot Weather Concreting Flashcards

7 cards from real ACI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Cold & Hot Weather Concreting flashcards as text

  1. When concreting in cold weather, what is the minimum concrete temperature recommended by ACI 306 for sections greater than 12 inches thick?

    Answer: 45°F (7°C)

    ACI 306 specifies a minimum placed concrete temperature of 45°F for sections greater than 12 inches thick, as thicker sections retain heat better.

  2. During hot weather concreting, which admixture type is most commonly used to counteract accelerated setting?

    Answer: Type B retarding admixture

    Type B retarding admixtures slow the hydration reaction, offsetting the accelerated setting caused by high temperatures.

  3. What is the primary risk of using calcium chloride as an accelerator in cold weather concrete containing embedded steel?

    Answer: It promotes corrosion of the reinforcement

    Calcium chloride is a chloride-based accelerator that can initiate and accelerate corrosion of embedded steel reinforcement.

  4. In hot weather, why should concrete be placed as quickly as possible after mixing?

    Answer: To avoid loss of slump and premature stiffening

    High temperatures accelerate hydration, causing rapid slump loss and premature stiffening if placement is delayed.

  5. Which curing method is particularly effective in cold weather because it provides both insulation and moisture retention?

    Answer: Insulating blankets with moisture underneath

    Insulating blankets placed over wet burlap or plastic sheeting trap both heat and moisture, satisfying cold-weather curing requirements simultaneously.

  6. ACI 305 defines hot weather concreting conditions as any combination of factors that causes what primary concern?

    Answer: Rapid evaporation of mixing water and accelerated setting

    ACI 305 focuses on rapid moisture evaporation and accelerated setting as the defining hot-weather risks that impair concrete quality.

  7. What effect does high concrete temperature have on the required air-entraining admixture dosage?

    Answer: More admixture is needed to achieve the same air content

    Higher concrete temperatures reduce the effectiveness of air-entraining admixtures, requiring increased dosage to achieve the specified air content.