The construction and development industry cannot be imagined in the absence of concrete. The paste made up of cement and water hardens over the time to form a rock-like substance. This hard rock-like substance formed is coined as concrete. Concrete is known for its high compressive strength and relatively low tensile strength. In order to impart certain characteristics in the concrete, admixtures are added either before or during the time of batch mixing. These admixtures strengthen the concrete to withstand many challenging and adverse conditions. These admixtures give a certain functionality or peculiarity to the concrete. These products enhance the performance of the concrete by imparting strength to it so that it can combat the challenging weather conditions in an effective manner. The inclusion of these admixtures can lead to increase or decrease of the setting time, enhanced quality, resistance to sulfate, superb finish, and much more. Basically, there are two types of admixtures i.e. chemical and mineral. The chemical admixtures are available in a powdered or liquid form, whereas, the mineral ones are available in the form of a fine grain. The functionality of the concrete so formed depends on the type of concrete admixture added while the batch mixing process.
Some of the chemical admixtures and their function are as follows-
• Water-reducing admixtures - These admixtures are added to reduce the water content of the concrete mix. This improves the workability of the concrete. Thus, the concrete having a water-reducing admixture like plasticizers, etc. require less water to be added to them in order to reach the desired results.
• Retarding admixtures - Incorporation of these types of admixtures lowers down the setting rate of the concrete. These admixtures are generally used under the hot weather conditions, as the concrete instantly sets under these conditions. Retarding admixtures prolong the setting up time of the concrete and enhance its workability during the placement.
• Accelerating admixtures - These admixtures increase the setting rate of the concrete. These admixtures are highly popular in areas prone to cold weather conditions. These admixtures speed up the construction process.
• Corrosion-inhibiting admixtures - These admixtures are generally added to the concrete mixes that are intended for jacketing steel. These admixtures slow down the rate of corrosion of the steel contained in the concrete structure.
Mineral admixtures for concrete are the inorganic materials having pozzolanic properties in them. Some of the mineral admixtures and their functions are as follows:
• Fly Ash - It is widely added as an admixture to the concrete mix in order to increase its strength and reduce the cost of concrete.
• GGBFS - The full form of GGBFS is Ground Granulated Brass Furnace Slag. It is formed as a by-product during the production of steel. It is capable of partially replacing the Portland cement.
• High reactivity Metakaolin (HRM) – As per the concrete admixture suppliers, this mineral admixture imparts strength and durability to the concrete. The vibrant white color of this admixture makes its apt for the construction of structures in which appearance is paramount.
Thus, we can conclude that concrete admixtures play a pivotal role in the field of construction and development.
This entry was posted on May, 28, 2020 at 15 : 15 pm and is filed under Admixture for Concretes. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response from your own site.