Definition Of A Concrete Additives And What Is It Used Mostly For?
A concrete admixture refers to materials other than water, aggregates, cementitious materials and fibre reinforcements that are added to a cementitious mixture to modify its properties. It is generally added before or during the mixing process.
Admixtures are usually liquids and added in very small quantities to the concrete while it is being mixed. There are different types of additives depending on how they affect freshly mixed or hardened concrete. They are concrete deflocculants, plasticizers, air-entraining agents, water-repellent admixtures, setting retarders and accelerators.
Why Are They Used?
Set Retarding Admixtures
Set retarding concrete admixtures are used to delay the chemical reaction that takes place when the concrete begins to set. Retarding additives are also used to reduce the effect of high temperatures that can hasten the setting process.
Set retarding admixtures are also used in concrete pavements as it increases the finishing time of concrete thereby reducing additional costs associated with placing a new concrete batch plant on a job site. Retarders can also be used to prevent cracking due to form deflection that can happen when horizontal slabs are placed horizontally in sections.
Air Entrained Admixtures
Air-entrained concrete can increase the freeze-thaw durability of concrete thereby making it more workable. The entrained air bubbles act as a shield against the cracking caused by stresses from water augmentation in freezing temperatures. Air entrainers are compatible with all types of concrete admixtures.
Water-reducing admixtures are chemical products when added to concrete create a slump at a lower water-cement ratio than what is normally expected. Water reducing admixtures are used to obtain a specific concrete strength using lower cement content.
Accelerating admixtures are used either to increase the strength of concrete or reduce its setting time. Calcium Chloride is the most commonly used accelerator although it can increase the corrosion rate of steel.
The main purpose of using plasticizers is to create flowing concrete with a high slump within the range of seven to nine inches to be readily used in heavily reinforced structures and in areas where consolidation by vibration cannot be easily achieved.
Vinplast 245 is a low molecular weight acrylic copolymer salt that is widely used in the construction industry as a concrete additive. Being specially designed for water reduction and improved workability, it can replace (Polycarboxylate Ether) in the admixture by 10% and offers many advantages like cost-reduction and improved product performance
Generally added before or during mixing, they can either increase the strength of the mix, accelerate it or slow down its curing process as necessary.
Newer types of admixtures are being researched today. Some provide environmental benefits and reduce pollution by reducing the need for Portland cement. As these poylmers begin to gain more acceptance, they are highly likely to play a larger role in the construction of buildings, roads and other concrete structures in the near future.
The wide range of Miscellaneous Polymers offered by Vinati Organics provide industries with many benefits like reduction in production cost without any depreciation in quality. Due to our research capabilities and expertise to develop new and environment friendly chemicals, we have managed to build a strong foothold in more than 35 countries in the world.