问题 问答题

影响沥青混合料高温稳定性的主要因素有哪些工程中如何提高沥青混合料的高温稳定性?

答案

参考答案:

沥青混合料的特点是强度和抗变形能力随稳定性的升高而产生变化。

(1)影响沥青混合料高温稳定性的主要因素

主要包括沥青和矿料的性质及其相互作用的特性、矿料的级配组成等方面。

(2)提高沥青混合料高温稳定性的措施

为了提高沥青混合料的高温稳定性,可采用提高黏结力和内摩阻力的方法。在混合料中增加粗矿料含量,或限制剩余空隙率,使粗矿料形成空间骨架结构,就能提高混合料的内摩阻力。适当地提高沥青材料的黏稠度控制沥青与矿粉的比值,严格控制沥青用量,采用具有活性的矿粉,以改善沥青与矿粉的相互作用就能提高混合料的黏结力。此外,在沥青混合料中使用掺入聚合物改性的沥青,也能取得比较满意的效果。

解析:

本题主要考查考生对影响沥青混合料高温稳定性的主要因素及工程中如何提高沥青混合料的高温稳定性的措施的理解程度,以便在质量监理中有效地进行控制,并对高温稳定性不足的情况提出改善措施。

单项选择题
阅读理解

阅读理解。

     Doctors may now be able to stop many heart attacks. An important new study reports that doctors have

a new drug. This drug is called TPA. It may be better than any other heart drugs.

     Many doctors now use a drug called streptokinase. But this drug sometimes causes problems for patients.

It can even cause bleeding(流血)in the brain. Some doctors do not use streptokinase. Streptokinase can save

about 1/3 of the people with heart attacks. But TPA will save about 2/3.

     One reason TPA can help more people is because of time. This new drug is easier and faster to use. It will

give doctors more time in hospitals. Then they can study the problem well. People with heart problems can

also keep some TPA at home. When a heart attack starts, they can take some TPA right away. Then they will

have time to get to the hospital. This is important because about 860,000 people in the United States die before

they get to the hospital.

     This is another reason why TPA is good news for people with heart attacks. According to the study, it is

much safer; it doesn't cause other problems like streptokinase does. TPA works only on the heart. It does not

have an effect on the blood or cause bleeding.

     Doctors plan to do more studies about TPA. They need to test this new drug on many more people with

heart attacks. But in a few years, many doctors and hospitals will probably start using this exciting new drug.

1. In your opinion, the best title for this passage is _____.

A. Heart Attacks

B. A New Drug for Heart Attacks

C. The Cause of Heart Attacks

D. A Drug Called Streptokinase

2. The story says that TPA_____ .

A. is safer and faster than the old drug

B. is very dangerous

C. is slower and harder to use than the old drug

D. causes many problems

3. This new drug may mean _____.

A. more people will die from heart attacks

B. the same number of people will die from heart attacks

C. fewer people will die from heart attacks

D. no one will die from heart attacks

4. Which of the following is TRUE?

A. Streptokinase is the new drug for heart attacks.

B. TPA can save fewer people with heart attacks than streptokinase.

C. People who take TPA at home before they go to hospital must be very careful.

D. Probably TPA will be widely used in America in the following years.