Types of concrete
There different types of concrete with various applications for several structures such as columns, beams, slabs, and foundations. Types of available concrete are explained here
The concrete has considerably lower mass per unit volume. The concrete made of ordinary ingredients is called lightweight concrete. The aggregates used are lighter in weight. The density of lightweight concrete is two between the range of 40 kg/m³-1850 kg/m³. The Strength of light weight concrete blocks varies from 7 MPa – 40 MPa.
At times Air Entrained Admixtures are also mixed with it to give it resistance to freezing and thawing and improved strength. Lightweight concrete is used where an extra load is not applied e.g. parapet, road lining, wall etc.
This is a type of concrete which is made up of common ingredient i.e. aggregate, water. It is also known as normal weight concrete and normal strength concrete. It has a setting period of 30 – 90 minutes depending on humidity and fineness of cement etc.
The normal concrete starts development of the strength starts after 7 days the common strength values is 10 MPa to 40 MPa. Curing time is about 28 days when it attains 75 – 80% of the total strength.
SELF COMPACTING CONCRETE
No vibration is required for this concrete. The concrete is compacted due to its own weight. It is also known as flowing concrete. It can be categorized as high-performance concrete as the ingredients are the almost the same, but in this type of concrete has enhanced workability.
If it is used in a location inaccessible for vibrations such as underground structure, deep wells or at the bottom of deep water body. Self-compacting concrete can save up to 50% of labor due to the faster pouring and reduced wear and tear
The high-performance concrete is prepared by carefully selecting ingredients and improvement of mix design. It has a high workability which is as a result of the superplasticizers they contain. It is highly durable because of the fly ash and silica fumes which modify its mineralogy. The strength of the high-performance concrete ranges between 10000psi and 15000psi.
Air entrained concrete
This is one of the greatest innovation in concrete technology. It is used where concrete is liable to freezing and thawing action. It lowers the surface tension of water and hence bubbles are created. Air-entraining admixtures are used to make entrained air in concrete.
Pervious concrete’s mass consists of an interconnected void structure that allows water to flow through at high rates. Typically, when casted on a sandy soil, the pavement will infiltrate stormwater at a higher rate than that of the soil below.
Structurally, pervious concrete is weaker than plain concrete with strengths less than 1000 psi. Because of the lower strengths, pervious concrete pavements are widely acceptable for light duty applications.