首页
登录
职称英语
What materials were not used for road surfaces during the last century? [br] [o
What materials were not used for road surfaces during the last century? [br] [o
游客
2023-12-14
63
管理
问题
What materials were not used for road surfaces during the last century? [br]
Mr. Jones: What materials were used for road surfaces during the last century?
Engineer: Usually they were gravel and macadam. Tars and asphalt were originally used only as coverings, but later they were used as binders and finally as hot mixtures.
Mr. Jones: Concrete is a modem material as far as road - building goes, isn’ t it?
Engineer: Relatively speaking. But you might be surprised to know that a concrete road was built as early as 1893 in Ohio. But it was only 5 miles long. More extensive projects were not undertaken until much later, around 1912 or 1913.
Mr. Jones: This was because of the increase in traffic?
Engineer: That’ s right. Especially in the use of heavy tracks. More rigid pavements, such as concrete and brick, became a necessity. For light traffic, though, water-bound macadam, gravel, sand clay, and bituminous mixtures were still used.
Mr. Jones: What are turnpikes usually made of?
Engineer: Turnpikes are usually made of reinforced concrete about 8 to 10 inches thick, placed on a granular sub-base, which in turn is placed on a well - tacked earth subgrade. Of course, the construction depends a lot on the local climate, rainfall, soils, and so on.
Mr. Jones: How do you mean--climate?
Engineer: Frost is one of the main problems. For example, in Maine, where frost is quite frequent, the typical turnpike construction is a thin top layer of asphaltic concrete on a base layer of sand and gravel placed on a 36 - inch, frost - free, granular subgrade.
Mr. Jones: What is the width of these roads?
Engineer: The early two - lane roads were about 20 feet wide. But with higher automobile speeds, the width requirements increased greatly. To give you an example, the Pennsylvania Turnpike has two 12 - foot lanes in each direction, separated by a median 10 feet wide. On each side there is a 10 -foot stabilized shoulder, marking a total width of 78 feet. The New Jersey Turnpike averages 100 feet in width, with three lanes in each direction.
Mr.Jones: I guess wider roads are being built every day.
Engineer: That’ s right. Sometimes you think that, no matter how good a road you build, the speed and weight of vehicles will always be one step ahead.
选项
A、Sand clay.
B、Macadam.
C、Brick.
D、Bituminous mixtur
答案
C
解析
The engineer指出:For light traffic, water-bound macadam, gravel, sand clay, and bituminous mixtures are used. "bituminous"为"like or containing any of various flammable mixtures of hydrocarbons and other substances that are constituents of asphalt and tar."含有沥青的。
转载请注明原文地址:https://tihaiku.com/zcyy/3272331.html
相关试题推荐
EconomicconditionshaveimprovedduringthepastdecadeinmanyNorthAmeric
EconomicconditionshaveimprovedduringthepastdecadeinmanyNorthAmeric
Duringthe1970’sand1980’spoliticalextremismandterrorismfrequentlyfoc
Duringthe1970’sand1980’spoliticalextremismandterrorismfrequentlyfoc
TennisDuringthefirst50yearsofitshistory,tenniswas
TennisDuringthefirst50yearsofitshistory,tenniswas
TennisDuringthefirst50yearsofitshistory,tenniswas
TennisDuringthefirst50yearsofitshistory,tenniswas
TennisDuringthefirst50yearsofitshistory,tenniswas
TennisDuringthefirst50yearsofitshistory,tenniswas
随机试题
Duringthelastthirtyyears,theinternationaleconomyhasexperiencedaba
[originaltext]W:Goodevening.MynameisJennyFowlerandIwouldliketowelc
IP数据报的分段和重装配要用到报文头部的()个字段。其中,分片偏移字段(段偏置
下列哪项是原发性肝癌的一级预防A.新生儿接种乙型肝炎疫苗 B.手术治疗 C.
表示肺癌已全身转移的表现是:A.痰中带血 B.持续性胸痛 C.股骨局部破坏
银行接到大规模投诉,或者投诉事项重大,涉及众多消费者利益,可能引发群体性事件的,
教语文的王老师对学生问的各式各样的问题倍感迷茫。比如“地球为什么是圆的”“叶子为
下列关于归责原则的叙述,正确的有( )。 A.归责原则,是确定责任归属所依据
个人汽车贷款采取()的,保证方应具备保证资格和贷款银行规定的保证条件。A.质押
(2017年真题)检验批质量验收时,主控项目必须全部符合有关( )的规定。A.工
最新回复
(
0
)