Describe the purpose of soil stabilization and discuss at least three methods of achieving it.

Question

What will be an ideal response?

Answer 1

Soil stabilization is performed to improve the engineering properties of
natural soils. There are two categories of soil stabilization, mechanical and
chemical. Mechanical stabilization is the blending of different grades of soils to
obtain the required grade. Chemical stabilization is the blending of the natural soil
with chemical agents. Cement stabilization usually involves the addition of 5% to
14% Portland cement by volume of the compacted mixture to the soil being
stabilized. This type of stabilization is usually used to obtain the required
engineering properties for base course materials. The process of stabilizing soils
with cement involves pulverizing the soil, mixing the required quantity of cement
with the pulverized soil, compacting the soil-cement mixture, and curing the
compacted layer.
Bituminous stabilization is carried out to achieve waterproofing of natural
materials and/or binding of natural materials. Waterproofing aids in maintaining
the correct moisture content and helps prevent water from seeping into the
subgrade, protecting the subgrade from failure due to an increase in moisture
content. Binding improves the durability characteristics of the natural soil by
providing an adhesive characteristic, whereby the soil particles adhere to each
other, increasing cohesion. Several types of soils can be stabilized with
bituminous materials, although it is generally required that less than 25% of the
material passes the No. 200 sieve. Lime stabilization can be used for stabilizing
both base and subbase materials. The materials most commonly used for lime
stabilization are calcium hydroxide and dolomite. Clayey materials are most
suitable for lime stabilization, but the materials should have plasticity index
values less than 10 for the stabilization to be most effective.