Core TradesCâu 13 / 700
Mechanical vibration of freshly placed concrete is done PRIMARILY to:
a.Consolidate the mix and drive out entrapped air pockets and voids
b.Increase the water-cement ratio for easier finishing
c.Speed up the chemical curing reaction
d.Add entrained air for freeze-thaw resistance
Giải thích
Vibration consolidates the concrete around reinforcement and expels entrapped air so the mass is dense and sound. Over-vibration actually causes segregation; it does not change the w/c ratio, speed curing, or add entrained air.
Trích dẫn luật: 2025 CA Building Code (CBC) Chapter 19 (Concrete)Luyện miễn phí toàn bộ 700 câu hỏi — không cần đăng ký.
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