REPLACEMENT OF CEMENT BY SILICA FUMES AND FLY ASH A PAPER ON REPLACEMENT OF CEMENT BY SILICA FUMES AND FLY ASH BY: KEDAR M. PATURKAR 4TH SEM B.E.(CIVIL) G. H. RAISONI COLLEGE OF ENGINEERING

BACKGROUND Energy plays a crucial role in growth of developing countries. In of low availability of nonrecoverable energy sources coupled with requirements of large quantities of energy to materials like cement, steel etc, the importance of industrial waste cannot be underestimated. In India about 110 million tonnes of fly ash is produced every year by 68 major thermal power stations.

BACKGROUND... It has been no understood that waste material like flyash and silica fume, through their use as construction material can be converted into meaningful wealth. A proportionate mix of flyash and silicafume in concrete improves property of concrete that may not be achievable through portland cement alone. The resulting concrete mix becomes strong, durable and economical and also ecofriendly as it utilizes an ecological hazardous material.

MATERIAL PROPERTIES AND APPLICATIONS A] FLYASH: It is waste product of mainly thermal power stations. The flyash in concrete converts the weaker C-H bonding to stronger C-S-H compounds by puzzolonic reactions. The heat generated during hydration initiates the puzzolonic reaction of fly ash.

B] SILICA FUME: Silica fume is byproduct of silicon or Ferro-Silica industry and 100 times finer than cement particle.(approx. diameter of 1 micrometre) It is commonly known as microsilica. The replacement level of silica fume is generally at about 10%. When silica fume is used in concrete mix , its introduction affects the physical arrangement of concrete near aggregate surface making the mix uniform and stronger.

PERFORMANCE OF CONCRETE WITH ADMIXTURES

SPLIT TENSILE STRENGTH

FLEXURAL STRENGTH TEST

RESULTS: The optimum percentage of cement replacement by flyash is 30% and silica fume is 12% for achieving maximum cube compressive, cylinder compressive, split tensile and flexural strenths. With the above replacements, concrete with a strength of 70 mPa can be produced with water to cement ratio of 0.3 with appropriate plasticizers. The transition zone gets improved and densified with the use of ternary mix concrete containing microsilica and flyash. Substantial savings of 50-55% can be achieved through total replacement levels of silica fume and fly ash.

REFERENCES: Concrete Technology by M. S. Shetty. Silica Fume User Manual by American Concrete Institute.

Thank you!!!

ANY QUESTIONS????