问题 问答题

某建筑工程欲采用抗压强度等级为C60、抗渗等级为P6、抗冻等级为F50的混凝土进行结构设计。已知该批混凝土拌和物的流动性较大,坍落度为15mm,混凝土拌和物中石子的粒径均小于40mm。建筑工程施工要求该批混凝土应易于操作,并具有能使所浇筑的构件质量均匀、成型密实的性能,并要求该批混凝土在长期使用环境中,在多种破坏因素作用下,均能够保持原有性能且不被破坏。
请根据上述条件,回答下列问题。

影响混凝土拌和物和易性的主要因素有哪些

答案

参考答案:影响混凝土拌和物工作性的因素较复杂,大致分为组成材料、环境条件和时间三方面。组成材料主要有:水泥的特性、用水量、水灰比、骨料性质等。

不定项选择
阅读理解

(2013·高考重庆卷,A)The morning had been a disaster.My tooth was aching,and I’d been in an argument with a friend.Her words still hurt:“The trouble with you is that you won’t put yourself in my place.Can’t you see things from my point of view?”I shook my head stubbornly-and felt the ache in my tooth.I’d thought I could hold out till my dentist came back from holiday,but the pain was really unbearable.I started calling the dentists in the phone book,but no one could see me immediately.Finally,at about lunchtime,I got lucky.

“If you come by right now,”the receptionist said,“the dentist will fit you in.”

I took my purse and keys and rushed to my car.But suddenly I began to doubt about the dentist.What kind of dentist would be so eager to treat someone at such short notice?Why wasn’t he as busy as the others?

In the dentist’s office,I sat down and looked around.I saw nothing but the bare walls and I became even more worried.The assistant noticed my nervousness and placed her warm hand over my ice­cold one.

When I told her my fears,she laughed and said,“Don’t worry.The dentist is very good.”

“How long do I have to wait for him?”I asked impatiently.

“Come on,he is coming.Just lie down and relax.And enjoy the artwork,”the assistant said.

“The artwork?”I was puzzled.

The chair went back.Suddenly I smiled.There was a beautiful picture,right where I could enjoy it:on the ceiling.How considerate the dentist was!At that moment,I began to understand what my friend meant by her words.

What a relief!

小题1:Which of the following best describes the author’s feeling that morning?

A.Cheerful.

B.Nervous.

C.Satisfied.

D.Upset.小题2:What made the author begin to doubt about the dentist?

A.The dentist’s agreeing to treat her at very short notice.

B.The dentist’s being as busy as the other dentists.

C.The surroundings of the dentist’s office.

D.The laughing assistant of the dentist.小题3:Why did the author suddenly smile?

A.Because the dentist came at last.

B.Because she saw a picture on the ceiling.

C.Because she could relax in the chair.

D.Because the assistant kept comforting her.小题4:What did the author learn from her experience most probably?

A.Strike while the iron is hot.

B.Have a good word for one’s friend.

C.Put oneself in other’s shoes.

D.A friend in need is a friend indeed.