What are Fluid Chemical Admixtures (Admix)?
Chemical admixtures are materials that are added to the concrete to give it certain characteristics not obtainable with normal concrete mixes. In normal use, admixture dosages are less than 5% by mass of cement and are added to the concrete at the time of batching/mixing. There 8 main uses or types of admixture for the concrete industry:
- Accelerators speed up the hydration (hardening) of the concrete. However, use of chlorides may cause corrosion in steel reinforcing and is prohibited in some countries, so that nitrates may be favoured. Accelerating admixtures are especially useful for modifying the properties of concrete in cold weather.
- Retarders slow the hydration of concrete and are used in large or difficult pours where partial setting before the pour is complete is undesirable.
- Air entraining agents add and entrain tiny air bubbles in the concrete, which reduces damage during freeze-thaw cycles, increasing durability. However, entrained air entails a trade off with strength, as each 1% of air may decrease compressive strength 5%. If too much air becomes trapped in the concrete as a result of the mixing process, defoamers can be used to encourage the air bubble to agglomerate, rise to the surface of the wet concrete and then disperse.
- Plasticisers increase the workability of plastic or “fresh” concrete, allowing it be placed more easily, with less consolidating effort. A typical plasticiser is lignosulfonate. Plasticisers can be used to reduce the water content of concrete while maintaining workability and are sometimes called ‘water-reducers’ due to this use. Such treatment improves its strength and durability characteristics.
- Pigments can be used to change the colour of concrete, for aesthetics.
- Corrosion inhibitors are used to minimize the corrosion of steel and steel bars in concrete.
- Bonding agents are used to create a bond between old and new concrete (typically a type of polymer) with wide temperature tolerance and corrosion resistance.
- Pumping aids improve pumpability, thicken the paste and reduce separation and bleeding.
Admixture Storage Tanks
Enduratank manufacture a complete range of bunded storage tanks for the processing and storage of bulk liquid admixture. Our bunded tanks have been specifically designed with pollution control in mind. Selected for integral protection from leakage and overfilling. These plastic tanks are constructed using rotationally moulded mid density polyethylene.
These bunded tanks contain a minimum 110% volume of the inner tank. Simply put, a bunded tank is a ‘tank within a tank’ which helps customers conform to current health and safety legislation.
Closed Top Bunded Tanks
Enduratank closed top bunded tanks are available in a wide range of sizes from 400 litre to 30,000 litre. Further storage capacities can be acquired by simply linking the tanks together with our tank connector kits. The customisation to a client’s specific requirements is available upon request.
Open Top Bunded Tanks
Like our closed top bunded tanks, our open top bunded tanks are also available in a wide range of sizes from 400 litre to 30,000 litre. Further storage capacities can be acquired by simply linking the tanks together with our tank connector kits. The customisation to a client’s specific requirements is available upon request.
For more information or to talk to one of our experts call us on 01778 562 810.