In: Civil Engineering
6) WHAT ARE THE DIFFERENCES BETWEEN CHEMICAL and MINERAL ADMIXTURES?
CHEMICAL ADMIXTURE | MINERAL ADMIXTURE |
Chemical admixtures are materials in the form of powder or fluids that are added to the concrete to give it certain characteristics not obtainable with plain concrete mixes. | while mineral admixtures are Inorganic materials that have pozzolanic or latent hydraulic properties, these very fine-grained materials are added to the concrete mix to improve the properties of concrete. |
chemical admixtures improve the quality of concrete during mixing, transporting, placing and curing. | mineral admixtures affects the nature of the hardened concrete through hydraullic or pozollanic activity. |
Chemical admixtures improve the workability of the concrete. | mineral admixtures improves the strength governing properties of concrete. |
chemical admixtures indirectly affects the strrength of cincrete | mineral admixtures directly affects the strength of the concrete. |
chemical admixtures are mixed in concrete at the timing of mixing. | mineral admixters are mixed in cement generally while manufactering. |
chemical admixtures are very intensive in nature and are required in very less quantity. Dosage ranges from 0.2% to 2% by weight of cement. |
mineral admixtures are not so much intensive and the quantity required is comparatively high. |
chemical admixtures also improves air entraining property, retarding and accelerating property of concrete, corrossion inhibitors, shrinkage controlling property of concrete | mineral admixture makes mixtures more economical (enables reduction in total cement content), reduce permeability , increase strength and influence other concrete properties. |
simple test on grouts such as marsh cone test or mini slump test can be a fair idea of compatibility between chemical admixtures and cementatious material. | there is no any specific test but by mixing admixtures in different ratios and testing the cement and concrete can lead to the proper quantity of admixture. |
eg. air entraining agents , plasticizers, superplasticizers, acceerating agents and retarding agents. |
eg. blast furnace slag, fly ash , silica fumes , rice husk, ash, GGBFS |