An aggregate’s voids are filled with moisture but the main surface area of the aggregate particles is dry. Which of the following moisture condition does it belong to（）
A. Bone dry
B. Air dry
C. Saturated surface–dry （SSD）
D. Moist
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After some water reducing agent is used into concrete, the function of the agent is（）if some water is reduced
A. to improve concrete mechanics
B. to reduce concrete cost
C. to change concrete workability
D. to increase concrete flowability
Which one in the following options might be disadvantage to the initial strength of cement concrete（）
A. use blast furnace slag cement
B. gap gradation is used for the cement concrete
C. the cement particle is too fine
D. water reducer is added in the cement concrete
A well-graded aggregate contains（）
A. Mostly particles passing the 4.75mm sieve
B. Particle sizes which are primarily within a small band
C. A range of particles sizes that are missing
D. Particles of all sizes in good distribution
When the slump of fresh concrete does not meet the requirement, the right way to improve workability is（）
A. Increasing cement paste under same W/C condition
B. Decreasing cement paste under same W/C condition
C. Adjusting cement paste under same W/C condition
D. Increasing or decreasing water quantity
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