Core TradesCâu 63 / 700
A large slab pour is interrupted for 3 hours when the concrete supply is delayed. When placement resumes, a visible line forms where fresh concrete meets the partially set concrete. This cold joint is BEST prevented in future pours by:
a.Planning continuous delivery and placing/vibrating fresh concrete into the previous lift before it takes initial set
b.Adding extra water to the delayed concrete
c.Increasing the slab thickness
d.Waiting until the first section fully hardens before continuing
Giải thích
A cold joint forms when a new lift is placed after the prior concrete has begun to set, so the two do not knit together. Prevention is continuous placement and revibrating fresh into the previous layer before initial set. Adding water weakens concrete; thickness is irrelevant; deliberately waiting for full hardening guarantees a cold joint.
Trích dẫn luật: 2025 CA Building Code, Chapter 19 (Concrete)Luyện miễn phí toàn bộ 700 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- During site grading, best management practices such as silt fences and fiber rolls are installed PRIMARILY to:
- A slab-on-grade develops a network of random, map-like surface cracks within days of placement, but the cracks are shallow and do not reach the reinforcement. What is the MOST likely cause?
- After stripping the forms from a concrete wall, the contractor finds voids with exposed coarse aggregate and no paste in several areas near the base. This honeycombing was MOST likely caused by:
- Fresh concrete is being placed into a tall wall form at a high rate on a cool day. The crew is concerned about lateral pressure on the forms. Which factor will MOST increase the lateral concrete pressure on the formwork?
- In a post-tensioned slab, the primary function of the tendons is to:
- A below-grade concrete basement wall shows persistent damp spots and mineral staining on the interior. The MOST effective long-term remedy is to:
Cập nhật gần nhất: · quy trình kiểm tra
Đội Ngũ Biên Tập PrepPass · Đối chiếu với California CSLB General Building (B) Trade Examination · Quy trình kiểm tra