Concrete is a construction material composed of cement, fine aggregates (sand) and coarse aggregates mixed with water that hardens over time. Portland cement is the type of cement most used for the production of concrete. There are different types of bonding materials other than cement, such as lime for lime concrete and bitumen for asphalt concrete used for road construction. Various types of cements are used for concrete works that have different properties and applications. Some of the cement types are Portland Pozzolana cement (PPC), quick hardening cement, sulphate resistant cement, etc.
The materials are mixed in specific proportions to obtain the required strength. The strength of the mixture is specified as M5, M10, M15, M20, M25, M30, etc., where M stands for Mix and 5, 10, 15 etc. as its resistance in kN / m2. In the United States, concrete strength is specified in PSI, which is pounds per square inch. The ratio of cement to water plays an important role that influences various properties, such as workability, strength and durability. An adequate proportion of water and cement is required for the production of manageable concrete.
When water is mixed with materials, the cement reacts with the water and the hydration reaction begins. This reaction helps the ingredients to form a hard matrix that binds the materials in a durable material similar to stone.
Concrete can be melted in any way. As it is a plastic material in its fresh state, various shapes and sizes of forms or formwork are used to provide different shapes, such as rectangular, circular, etc. Several structural elements are constructed such as beams, slabs, footings, columns, lintels, etc. concrete.
The requirements of the ACI 318 construction code for structural concrete and the ACI 301 specifications for structural concrete are used in the United States as a standard code of practice for concrete construction. There are different types of mixtures that are used to provide certain properties. Additives or additives such as pozzolans or superplasticizers are included in the mixture to improve the physical properties of the wet mix or the finished material.
Several types of concrete are currently manufactured for the construction of buildings and structures. These have special properties and characteristics that improve the quality of the construction according to the requirements.