Durability is defined as the capability of concrete to resist weathering action, chemical attack and abrasion while maintaining its desired engineering properties. It normally refers to the duration or life span of trouble-free performance. Different concretes require different degrees of durability depending on the exposure environment and properties desired. For

Ordinary Portland Cement (OPC) is highly alkaline in nature with pH values above 12. When the cement paste comes into contact with the acids its components break down, this phenomenon is known as acid attack. If pH decreases to values lower than stability limits of cement hydrates, then the corresponding hydrate loses calcium and decomposes to amorphous hydrogel.

Normal concrete High Strength Concrete High Performance Concrete Air Entrained Concrete Light Weight Concrete Self Compacting Concrete Shotcrete Pervious Concrete Roller Compacted Concrete The concrete in which common ingredients i.e. aggregate, water, cement are used is known as normal concrete. It is also called normal weight concrete or normal strength concrete.

Hydropower planning covers a wide range of topics. Professionals from many disciplines take part in the planning and implementation of hydropower projects.

Hydraulic jump is the phenomenon of open channels. Before defining the hydraulic jump it is necessary to describe the terms "super critical flow" and "sub critical flow" in order to clearly understand that "what is hydraulic jump" Hydraulic jump usually occurs in super critical flow. In order to describe the super critical flow and sub critical flow, there is need to define the