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
2024-12-27
13
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、the increase in traffic
B、the cost of other materials
C、the change of the climate
D、the construction of the roads
答案
A
解析
concrete为"a constraction material consisting of sand, conglomerate gravel, broken stone, or slag in a mortar or cement matrix"混凝土。
转载请注明原文地址:https://tihaiku.com/zcyy/3886888.html
相关试题推荐
AtraditionalfoodenjoyedbyAmericansduringThanksgivingDayis______.A、stea
Historybuffsstillwaxpoeticaboutthebrutalpatentbattlesacenturyago
IfAmericahadanationalpoetinthe20thcentury,itiscertainly______.A、Fros
Insixteenth-centuryItalyandeighteenth-centuryFrance,waningprosperity
Insixteenth-centuryItalyandeighteenth-centuryFrance,waningprosperity
Insixteenth-centuryItalyandeighteenth-centuryFrance,waningprosperity
Withtheconstructoroftherailwaysinthe19thcentury,anewsociological
Withtheconstructoroftherailwaysinthe19thcentury,anewsociological
Withtheconstructoroftherailwaysinthe19thcentury,anewsociological
SayingthatPabloPicassodominatedWesternartinthe20thcenturyis,byn
随机试题
Hewasluredintoacrimehewouldnot______havecommitted.A、actuallyB、accide
A【B1】______ofthephysicalandchemicalnatureoflifemustbegin;noton
机械静联接多数属于()。A.可拆联接 B.不可拆联接 C.焊接 D.以上均
某双车道公路隧道采用全断面法开挖掘进,对该隧道进行施工监控量测,请回答以下问题。
土工织物用作反滤材料时,要求()。A.能阻止土颗粒随水流失 B.具有一定的透
建设工程合同签订以后,发包人给承包人一定比例的预付款,一般为合同金额的()。A
根据步行动作路线观察调查方法,估算一个店铺销售额的公式是( )。A.销售额=动
某乙烯裂解炉年运行时间8000小时,每年计划清焦作业5次,每次36小时,烟气排放
评标委员会在向招标人提交的书面评标报告中应当记载的内容有()A.基本情况和数据
高血压合并稳定型心绞痛应选用的药物是( )。A.美托洛尔 B.钙通道阻滞剂
最新回复
(
0
)