Attempts are also being made to produce concrete with more strength and durability, and

with a lighter weight. One system that helps cut concrete weight to some extent uses polymers, which are long chainlike compounds used in plastics, as part of the mixture. 180. The current trend of structural materials is B . A. to develop heavier materials B. to develop lighter materials C. to develop less materials

181. Aluminum weighs A . A. much less than steel B. the same as steel C. much heavier than steel

182. Aluminum has C . A. no properties of steel B. few properties of steel

C. many of the same properties of steel

183. Which of the following is true? B

A. Aluminum beams can?t be used for bridge construction

B. Aluminum beams can be used for not only bridge construction but also the framework of

a few buildings

C. Aluminum beams can?t be used for the framework of a few buildings

Passage Three

Steel and concrete also complement each other in another way: they have almost the same

rate of contraction and expansion. They therefore can work together in situations where both compression and tension are factors. Steel rods are embedded in concrete to make reinforced concrete in concrete beams or structures where tension will develop. Concrete and steel also form such a strong bonds—the force that unites them—that the steel cannot slip within the

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concrete. Still another advantage is that steel does not rust in concrete. Acid corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid. 184. Steel and concrete have C . A. different rate of contraction B. different rate of expansion

C. almost the same rate of contraction and expansion 185. Reinforced concrete is A .

A. steel rods which are embedded in concrete beams B. concrete which is embedded in steel rods C. steel rods which react with concrete 186. Which of the following is true? C A. steel can rust in concrete B. concrete can corrode steel C. steel does not rust in concrete 187. Concrete has B .

A. some kind of chemical that corrodes steel B. an alkaline chemical reaction, the opposite of acid C. some kind of acid

Passage Four

The employer or promoter of civil engineering works normally determines the conditions of contract, which define the obligations and performances by some form of competitive tendering and any contractor who submits a successful tender and subsequently enters into a contract is deemed in law to have voluntarily accepted the conditions of contract adopted by the promoter.

The obligations that a contractor accepts when he submits a tender are determined by the form of the invitation to tender. In most cases the tender may be withdrawn at any time until it has been accepted and may, even then, be withdrawn if the acceptance is stated by the promoter to be

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?subject to formal contract? as is often the case.

188. The conditions of contract are normally determined by C . A. the government official B. the contractor C. the promoter

189. This conditions define the obligations and performances to which ___C___ will be subject. A. the employer B. the official C. the contractor

190. The obligations that ___C___ accepts when he submits a tender are determined by the form

of the invitation to the tender. A. the employer B. the auditor C. the contractor

191. In most cases the tender may be withdrawn at any time until B . A. the promoter has enough money B. it has been accepted

C. the tender approved by the government

Passage Five

Materials are usually described as ?rock?, ?loose rock?, or ?common?, with ?common? signifying all material not otherwise classified. Rock, sometimes called ?solid rock?, nearly always must be drilled and blasted, then loaded with a front-end loader or power shovel into trucks or other hauling units. Blasted rock may be moved or drifted for short distances by means of a bulldozer, which is, in effect, a huge tractor-mounted blade. Loose rock often is dug with loaders or shovels without any previous blasting.

192. According to the passage, which material signifying all material not otherwise classified.

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B

A. loose rock B. common C. rock

193. Which of the following is NOT true? B A. rock, is sometimes called ?solid rock?

B. rock, is sometimes called ?loose rock? C. rock, is usually called ?hard rock

194. According to the passage, which of the following is true? B A. loose rock nearly always must be drilled and blasted B. loose rock is often dug without any previous blasting C. blasted rock may be moved for long distances by bikes

195. Loose rock often is dug with ___B___ without any previous blasting. A. track or ripper B. loaders or shovels C. roller or bulldozer

Passage Six

In the university, mathematics, physics, and chemistry are heavily emphasized throughout the engineering curriculum, but particularly in the first two or three years. Mathematics is very important in all branches of engineering, so it is greatly stressed. Today, mathematics includes courses in statistics, which deals with gathering, classifying, and using numerical data, or pieces of information. An important aspect of statistical mathematics is probability, which deals with what may happen when there are different factors, or variables, that can change the results of a problem. Before the construction of a bridge is undertaken, for example, a statistical study is made of the amount of traffic the bridge will be expected to handle. In the design of the bridge, variables such as water pressure on the foundations, impact, the effects of different wind forces,

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