Foundation is often rest on natural rock. The rocks are found to be eroded due to different erosion agent of ambient environment. Dear reader we have discussed about formation of soil, erosion of rocks, both chemical and physical properties of such soil.
When foundation of a structure rests on rock, the stability and subsequent damage of foundation depends on strength and durability of rock. Some rocks have greater strength but posses lesser durability and durability is very important factor in respect to longevity of foundation and structure over it.
The strength and durability of rock depend on distribution and amount of weaker and smaller mineral within it. When these minerals get worn out, everything is also broken down or dissolved which results no interaction between stronger minerals that once connected to each other by strong mineral bond.
These wearing actions left nothing but a stone that is merely composed of conglomeration of loosely connected particles. The deterioration accelerates when foundation surface is damaged, in addition, by following:
a. Frost action
b. Salt washing and like other process
Now how much time is required to take place such erosion process?
The usual duration is long. But some special rocks produce problem when exposed to erosion; these are
c. Shale etc.
In our next post we will learn about foundation damage due to deterioration of bricks used as foundation material. Till then good bye.