Mineral Admixtures for High Performance Concrete

Abstract

The development of Mineral Admixtures for High Performance Concrete (HPC) has brought about the essential need for additional ingredients. This paper is an attempt to study the behavior of Silica Fume and Metakeolin (8%, 10%, and 12% replacement by weight of cement) along with Fly Ash (20%) on fresh & hard property of concrete.

(i) For fresh property of concrete workability test is performed and results are compared with respect to dosage variations of minerals (8%, 10%, 12%) and also with each other, test results includes Initial Slump, Slump after 30min and Slump after 60min, from which slump loss is calculated after 30min and 60min respectively.

(ii) For hardened concrete the development of compressive strength of Minerals at the age of 1, 3, 7 and 28 days are investigated and compared with respect to mineral dosage variations and also with each other, for durability point of view Permeability test is performed and test results are compared. This work also includes cost comparison analysis between each minerals used. Based on all the results mineral type and its proportion is to be used can be finalized.

Conclusion

In high performance concrete mix design as water cement ratio adopted is low, it is necessary to maintain super plasticizers for required workability. When the percentage of mineral admixtures in the mix increases super plasticizer percentage also increases for obtaining of required strength.In case of combination percentage replacement of mineral admixtures the maximum compressive strength achieved in M80 grade concrete in 89.3 Mpa with replacement of cement by15% fly ash and 5% Metakaolin Mineral admixtures such as Fly ash, micro silica, metkaolin& Slag also contribute effectively for achieving high strength.