Composition of Concrete & Importance of Concrete Testing
Concrete is considered to have resistance against natural disasters like windstorms, flood etc. and is used as an exterior skin on buildings. Though concrete is reliable for strong building structure, yet concrete manufacturers are concerned with its quality and reliability.
There has been a great need to test concrete before being used in buildings in order to remain safe from disasters. It is often observed that building contractors are blamed of using concrete of lower quality. Concrete is also beneficial against fire conditions as the concrete walls and roofs give protection to human lives when the building catches fire and it is possible only when concrete is made up to the standards. That is why testing of concrete has been a great issue for concrete manufacturers and civil engineers for the last many years.
Concrete is the primary material used in buildings. To test the durability of concrete some standards are employed. These standards are adopted by laboratories throughout the world to test and examine the composition of ingredients used for concrete .These standards are normally used to check hardness, elasticity, and strength of concrete. Old standards are being updated and replaced by new standards in concrete testing with the help of modern technologies.
Before stating the importance of concrete testing, let's have a look on the composition of concrete, as the properties of ingredients used in concrete determine the properties of concrete. Concrete is a mixture of water, aggregates, and cement.
Water and cement hold the stones and sand together to form concrete. This mixture is mixed together to form the plastic mass which can be molded into the desired shape. When this paste gets hard it becomes like a rock. In order to get a rock hard and durable concrete, it is important to test the composition of its ingredients.
Now let us consider each ingredient used to make concrete. The main ingredient of concrete is cement which is available in many types. Each type has different chemical composition which can give different properties to concrete. Therefore, it is quite necessary to test the quality of cement before getting the desired form of concrete.
Water is also an important factor in determining the quality and durability of concrete. Water is used for hydration in making concrete. Presence of any impurities in water may affect the quality of concrete. Pure drinking water is considered ideal in concrete making, as it is free of impurities, such as minerals and salts. Sea water is not suitable for concrete making.
Other ingredients of concrete are stones and sand. These ingredients must also be clean and free from any contaminating substances in making durable and fine quality of concrete. Aggregates should not contain substances like wood, humus, and coal. The weak nature of substances like wood or coal can affect the durability of concrete. Presence of water soluble salts like chloride and sulphates in aggregate (sand and stone) are not desirable for a fine concrete. Furthermore, aggregates must also be hard and strong. Concrete producers take keen interest in the shape and size of aggregates as it can play an important role in the formation of desired and durable concrete.
