1. What is the British method of the mix design of the soil-cement mix based on?
a) Stability
b) Durability
c) Compressive strength at 28 days
d) Compressive strength at 7 days
Explanation: There are two methods that are commonly used to design the soil-cement mix. They are the British method and the PCA method. The British method is based on the compressive strength of samples cured for seven days and the PCA method is based on the durability of the mix.
2. The strength of soil-lime stabilization depends on ______ content of the soil type
a) Water
b) Pozzolana
c) Clay
d) Organic
Explanation: The type of soil is an important parameter influencing lime stabilization. The pozzolanic action of lime and soil helps in bringing about the stabilization. Therefore, the pozzolana content of soil gives a measure of the strength of the lime stabilized soil.
3. ______ has been found more effective than using hydrated lime for stabilization.
a) Quick lime
b) Slaked lime
c) Fat lime
d) Hydraulic lime
Explanation: Quick lime is effective because it gives good results in a short period of time, but it is not used because of its corrosive nature. Slaked lime is hydrated lime. Fat lime is rich in calcium content and hydraulic lime contains clay.
4. What is the name of the point when the plastic limit starts decreasing on increasing lime content?
a) Plastic lime point
b) Lime stabilized point
c) Plastic reduction point
d) Lime fixation point
Explanation: Lime is added to the soil in the presence of water and it increases the plastic limit of the soil and decreases the plasticity index of the soil. If further lime is added, then after a certain point the plastic limit starts decreasing. This point is termed as the lime fixation point.
5. When clayey soil is treated with lime ______ takes place.
a) Anionic exchange
b) Cationic exchange
c) Pozzolanic reaction
d) Thermal reaction
Explanation: Ion exchange is the main principle involved in the soil-lime stabilization process. A cationic exchange takes place between clayey soil and lime. It increases its stability after reducing the plasticity index.
6. The strength gain of lime-soil stabilized soil is dependent on which of the below factors?
a) Temperature
b) Humidity
c) Minerals
d) pH
Explanation: The strength gain of lime-soil stabilized soil is dependent on temperature. the rate of strength gain is higher at higher temperatures. It is considered to be almost zero in freezing conditions.
7. Which ions from hydrated lime and soil are involved in the ion exchange process?
a) Calcium and sulphate
b) Sulphate and water
c) Calcium and water
d) Calcium and silicate
Explanation: Cationic exchange takes place when hydrated lime reacts with clay particles. The calcium ions from hydrated lime replace the water ions. As a result, the soil becomes friable and granular enabling better compaction and mixing.
8. Which of the below is not an additive used for the lime stabilization of soil?
a) Sodium metasilicate
b) Sodium carbonate
c) Sodium hydroxide
d) Sodium sulphate
Explanation: Sodium carbonate is an additive that is used in the soil-cement stabilization. Sodium metasilicate, sodium hydroxide and sodium sulphate are the additives that are used in the lime stabilization of soil.
9. Lime stabilization can easily be applied to alluvial silts.
a) true
b) false
Explanation: Lime stabilization is suitable for soils like clay, silty clay and clayey gravel. It is generally not used for sandy and granular soils. So, the lime stabilization method can be used for alluvial silts.
10. Lime column is a special technique that is used to stabilize the soil.
a) true
b) false
Explanation: Lime column is a special technique that is used to stabilize the soil. This technique uses an auger to form bores in which lime is mixed with the in-situ soil. This is used for strengthening the weaker foundation for buildings.