The history of concrete, the world’s most frequently used building material, can be traced back to the Romans and ancient Egyptians. Given that concrete is used twice as frequently as all other building materials in construction, a focus on quality, performance and sustainability is critical for the industry’s growth and success. Concrete admixtures in Malaysia are one of the most significant ingredients in today’s high-performance, long-lasting, durable, and aesthetic concrete to build Malaysia’s higher education institutions. Concrete admixtures are natural or synthetic chemicals or additions that are mixed into fresh or hardened concrete to improve certain attributes such as workability, durability, or early and final strength. The following are the four types of concrete admixtures that are available in Malaysia:
- Water reduction in the mix
Water reducers have grown so significant in concrete that they are sometimes referred to as the “fifth” element. They can be used to lower the water-cement ratio, increase slump or reduce the content of cement. Superplasticizers are classified as Low Range, Mid Range, or High Range water reducers. There are numerous admixtures to choose from to fulfil the needs of a certain project, whether it’s tall columns that require a mix that pumps readily or a robust floor slab that’s simple to finish. They give the appropriate slump with less water in the mix, and they may produce higher strength concrete without adding more cement.
- Retarding admixtures
Retarding admixtures reduce the rate of hydration of cement in its early stages and extend the time it takes for concrete to cure. These are also known as retarders, and they are commonly employed in high-temperature areas where concrete sets quickly. In rare cases, a rapid setting can cause structural discontinuities, poor bonding between surfaces, and unwanted gaps in concrete, among other things. Retarders might help you get rid of these kinds of issues. Calcium sulphate or gypsum are two often used retarding admixtures. Other retarders include starch, cellulose derivatives, ordinary sugar, and acid salts. The majority of water lowering admixtures also function as retarding admixtures and are referred to as retarding plasticizers.
- Strength enhancement
Superplasticizer admixtures can be used to increase the strength of concrete by lowering the water/cement ratio, resulting in high-performance concrete. These admixtures help to create a high-slump, exceptionally flowable concrete that achieves high strengths while being easy to work with and pump. Water-reducing admixtures with a wide range of properties can also be employed in precast/prestressed constructions when a low water/cement ratio is desired for low permeability and strong early strengths without set retardation. They’re also employed for concrete that needs to be stripped quickly.
- Pozzolanic admixtures
Pozzolanic admixtures are used to provide a dense concrete mix that is ideal for water-holding structures such as dams and reservoirs. They also help to minimise hydration heat and shrinking. The use of the best pozzolanic materials in the right amounts produces the greatest results and lowers or eliminates various dangers such as alkali-aggregate reaction, leaching, and sulphate attack. Natural or synthetic pozzolanic minerals are utilised as admixtures.