Concrete Technology MCQ – Aggregate MCQ

231. Consider the following statements:

1. A high aggregate impact value indicates strong aggregates.
2. A low aggregate crushing value indicates high crushing strength of aggregates.
3. Aggregates having elongation index values greater than 15% are generally considered suitable for pavement construction.
4. Flakiness index of aggregates should not be less than 25% for use in road construction.

Which of the above statements are correct?

1. ii and iii only
2. ii and iv only
3. i and iii only
4. i and iv only

232. Consider the following statements regarding Cyclopean concrete:

1. Size of aggregate is more than 150 mm.
2. Size of aggregate is less than 150 mm
3. High slump
4. High-temperature rise due to heat of hydration.

Which of the above statements are correct?

1. i and iii only
2. i and iv only
3. ii and iii only
4. ii and iv only

233. Pozzolana used as an admixture in concrete has the following advantages:

1. It improves workability with lesser amount of water.
2. It increases the heat of hydration and so lets the concrete set quickly
3. It increases the resistance of concrete to attack by salts and sulphates.
4. It leaches out calcium hydroxide.

Select the correct answer using the codes given below:

1. i, ii and iv only
2. i, ii and iii only
3. ii, iii and iv only
4. i, iii and iv only

234. Consider the following statements:

1. If more water is added to concrete for increasing its workability, it results into concrete of low strength.
2. No slump is an indication of a good workable concrete.
3. Higher the slump of concrete, lower will be its workability
4. Workability of concrete is affected by water content as well as water-cement ratio.

Which of the above statements are correct?

1. i and iii only
2. ii and iii only
3. i and iv only
4. ii and iv only

235. Consider the following statements:

1. Workability of concrete increases with the increase in the proportion of water content
2. Concrete having small-sized aggregates is more workable than that containing large sized aggregate
3. For the same quantity of water, rounded aggregates produce a more workable concrete mix as compared to angular and flaky aggregates
4. A concrete mix with no slump shown in the slump cone test indicates its very poor workability

Which of the above statements are correct?

1. i, ii and iii only
2. i, ii and iv only
3. i, iii and iv only
4. ii, iii and iv only

236. The yield of concrete per bag of cement for a concrete mix proportion of 1: 1.5: 3 (with adopting 2/3 as the coefficient) is

1. 0.090 m³
2. 0.128 m³
3. 0.135 m³
4. 0.146 m³

237. Consider the following statements:

1. Rich mixes are less prone to bleeding than lean ones
2. Bleeding can be reduced by increasing the fineness of cement

Which of the above statements is/are correct?

1. i only
2. ii only
3. Both i and ii
4. Neither i nor ii

238. In handling air-entraining admixtures the beneficial amount of entrained air depends upon certain factors like

1. Type and quantity of air-entraining agent
2. Water-cement ratio of the mix
3. Strength of aggregates
4. Extent of compaction of concrete

1. i, ii and iii only
2. i, ii and iv only
3. i, iii and iv only
4. i, ii, iii and iv

239. Which of the following methods will help in reducing segregation in concrete?

1. Not using vibrator to spread the concrete
2. Reducing the continued vibration
3. Improving the cohesion of a lean dry mix through addition of a further small quantity of water

1. i, ii and iii
2. i and ii only
3. i and iii only
4. ii and iii only

240. Permeability in concrete is studied towards providing for, or guarding against, which of the following features?

1. The penetration by materials in solution may adversely affect the durability of concrete; moreover, aggressive liquids ‘attack’ the concrete.
2. In case of reinforced concrete, increase of moisture and air will result in corrosion of steel leading to an increase in volume of steel, resulting in cracking and spalling of the concrete cover.
3. The moisture penetration depends on permeability and if the concrete can become saturated with water it is less vulnerable to frost action.

1. i, ii and iii
2. i and ii only
3. i and iii only
4. ii and iii only