Types of Concrete

Today, our urban centers can be called 'jungles of concrete'. This wonder material is everywhere around us. Basically, concrete is a material used for construction purpose and is composed of Portland cement mixed with strengthening material like aggregate (gravel, granite, limestone, sand), fly ash and slag cement, water, and additives if any. There are many kinds of concrete mixes depending on the various factors, like proportion of aggregate, production procedure, usage, etc. Here is a list of the most commonly found concrete types but before that a brief about concrete.

Concrete: How to Make

The most popular way of making concrete is using Portland cement and mixing mineral aggregates and water with it. Concrete solidifies quickly as the cement components hydrate and glues all the added aggregate together. The concrete thus formed has high compressive strength and it is generally used for making pavements, gates, fences, walls, slabs and more. External additives and stabilizers are added to the concrete to impart it with some desired characteristics. In earlier times, concrete would often be referred to as liquid stone. Here are some of the major concrete types.

Different Types of Concrete

Concrete Type	Description
Cement Concrete	This is the most widely used type of concrete and is made by mixing Portland cement with sand, fine mortar and water. The proportion of cement, sand and mortar may vary from 1:1:2 (considered the best quality mixture) to 1:3:6 (a low quality mixture mostly used for concrete filling).
Reinforced or Structural Concrete	In this type, lightweight cement concrete is reinforced with metal rods to impart tremendous load bearing capacity. Concrete of such quality is suitable for those structures that have to bear large weights like beams and columns. If reinforced concrete is made in its compact form using stone aggregate, it has comparatively higher density (about 2.4) which further enhances its great strength.
Plain Mass Concrete	This type of concrete is not strengthened by any reinforcements. It is mainly used in structures like foundations, certain types of concrete slabs, dams, and concrete block retaining walls on bridges and overpasses. This type may also be called non-reinforced concrete.
Lean Concrete	It is a plain type of concrete with a larger aggregate to cement ratio than structural concrete. Lean concrete is mainly used for filling and not structural duties, as it has low weight bearing strength.
Prestressed Concrete	It is a type of structural concrete which is compressed using high pressure in those parts which are subjected to extreme tensile forces so that the concrete is not in a state of tension when actually under the working load.
Vacuum Concrete	Vacuum concrete contains high water content which allows sufficient ease while working and placing it into complicated molds or while doing extensive reinforcement. This concrete is then subjected to a vacuum that ensures that no excess quantities of water is retained, which in turn ensures a stronger concrete on hardening.
Cast in Place /Cast in Situ Concrete	The cast in place concrete is just deposited in its desired position to harden. This is one common method used in construction of concrete roads where the concrete is directly deposited on the ground.
Precast Concrete	These concrete blocks are placed in separate molds, under controlled conditions, to harden and whenever needed, transported to the site for final erection. This procedure gives high quality concrete castings and that too at a relatively low cost. This concrete is used for paving slabs, road channels, kerbs, lintels, bricks, fence posts, bridge beams etc.
Pumped Concrete	This concrete is transported through pipes from the mixer to where it is deposited. The concrete is prepared by discharging it from the mixer into a hopper which feeds it to a pump which pushes it through a pipe. Standard pipes are 100 or 150 mm in diameter and can be used to pump this concrete over horizontal distances of 650 m or vertical heights of 50 m, or permutations of these lengths.
Spun Concrete	This type of concrete is used for the production of pipes and vessels with curved surfaces. The process of manufacturing involves feeding fairly dry concrete into a rotating cylindrical molds. This mix is flung against the curved wall by centrifugal action to make a dense hard impermeable piped structure.
Ready Mixed Concrete	Ready mixed concrete is manufactured at mixing plants and delivered to the construction site in specially designed vehicles. The vehicle has a large rotating drum in which the concrete continuously mixes until it is delivered to the site. The mix specification is first decided by the supplier and the contractor, prior to delivery.
High Density Concrete	High density concrete is used to build nuclear shield walls, ballast blocks and sea walls. It is produced using different materials in place of aggregate, like iron shot, steel shot and lead shot or barytes and haematite.
Water Resistant Concrete	Water resistant concrete includes water proofed or watertight concrete. Waterproofed concrete is manufactured when a water resistant layer or surface is added on the mass of ordinary concrete. Concrete waterproofing is done by laying a water tight layer on ordinary concrete by applying a coat of asphalt or bitumen using a spray of lacquer or even by using water glass. Watertight concrete is produced by formulating a denser product of waterproof type by using strict quality control of a similar process. The concrete so formed is highly water-tight so as to enable its use in water tanks for retaining water.
Fiber Reinforced Concrete	By including short fibers in the mix of normal reinforced concrete, very high strength, high performance concrete can be produced. Concrete so formed has an enhanced impact resistance and greater strength. This is an area which is still under a lot of study and research.

Hope this list of concrete types proves helpful and makes a remarkable addition to your knowledge on this extraordinary construction material.