This set of Pavement Design Multiple Choice Questions & Answers (MCQs) focuses on “Soil-Lime Stabilization – 2”.
1. Which of the below is a not a type of soil and lime reaction?
c) Cation exchange
Explanation: Diffusion is not a type of soil and lime reaction. The lime diffuses into the soil and causes changes to it. Flocculation, aggregation and cation exchange are all different types of soil and lime reaction.
2. Which of the below field tests conducted on lime stabilized soil are to be checked after compaction?
c) Dry density
d) Moisture content
Explanation: There are two field tests used to check the proper construction. They are moisture content test, which is checked during compaction and the other test is for dry density, which is checked soon after the compaction is done.
3. Soil lime stabilization cannot be used in the surface course.
Explanation: Just like soil cement stabilization, the lime stabilization also cannot be used in the surface course. The low resistance to abrasion, impact and wearing makes it unsuitable for use in the surface course.
4. What is the next step in the construction process after lime is spread over the soil?
a) Mixing the lime and soil
b) Adding rest of the lime
c) Leaving it for reaction time
d) Compacting the mixture
Explanation: After the lime is spread on top of the soil and missed slightly, it is left undisturbed for a few days. This is because the soil and lime reaction is slow and requires some time. After this, the rest of the lime is mixed with the soil.
5. Which of the below represents an adverse chemical reaction that can probably occur when treated with lime?
Explanation: Carbonation in the lime treated soil represents the reaction between the free lime and atmospheric carbon dioxide, forming calcium carbonate. The compound formed has weak bonding and thus it represents the weak spots in the soil.
6. The maximum dry density of soil is ______ by ______ compared to untreated soil.
a) Decreased, 2 to 3%
b) Increased, 2 to 3%
c) Decreased, 4 to 5%
d) Increased, 4 to 5%
Explanation: There is a decrease in the maximum dry density of treated soil by 2 to 3% when compared to untreated soils. A small addition of lime makes this change to the soil, but it does not change the strength of soil much.
7. The final curing can be provided to the treated soil in the form of membrane curing.
Explanation: The final curing can be provided to the soil in two ways – moist curing and membrane curing. The method of moisture curing consists of light sprinkling of water. Membrane curing involves sealing the soil with a bituminous material.
8. Which of the below is not the right immediate effect of soil treatment using lime?
a) Reduced plasticity index
b) Improved bearing capacity
c) Drop in optimal water content
d) Reduced maximum dry density
Explanation: The optimal water content rises that makes the soil easy to compact. The immediate effect includes the reduction in plasticity index, improved bearing capacity and reduction in maximum dry density. The plastic soil is changed to a crumbly soil, the CBR value is 4 to 10 times higher for a treated soil in almost two hours after treatment.
9. The pH of the soil is found to quickly ______ to ______ when adequate quantities of lime and water are added to it.
a) Increase, 10
b) Decrease, 4
c) Increase, 10.5
d) Decrease, 4.5
Explanation: The pH of soil increases to 10.5 very fast when lime and water are added to the soil. The sudden increase in the pH value of soil helps in breaking down the clay particles, which in turn aid in the stabilization process.
10. Which of the below options is not another name used for hydrated lime?
a) Slaked lime
b) Water lime
c) Garden lime
d) Calcium hydroxide
Explanation: Hydrated lime is obtained by the slaking of quick lime, hence it is also known as slaked lime. The chemical formula for the same is calcium hydroxide. Since it is used in gardens to increase the pH of the soil, it is also referred to as garden lime. Hydraulic lime is also known as water lime.
Sanfoundry Global Education & Learning Series – Pavement Design.
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