Mechanical Strength of Concrete using Bottom Ash as Fine Aggregate

Concrete is a material synonymous with strength and longevity. In addition to being durable, concrete is easily prepared and fabricated from readily available constituents and therefore widely used in all types of structural systems. The Indian Construction Industry is today consuming about 400 million tons of concrete every year and it is expected that this may reach a billion tones in less than a decade. All the materials required to produce such a huge quantity of concrete come from the earth's crust. Thus, it depletes its resources every year creating ecological strains. Recent technological development has shown that the waste solid materials are valuable as inorganic and organic resources and can be used to produce various useful products.

Bottom ash is a byproduct of coal combustion. The largest producers of bottom ash are coal fired power plants, which burn a very high volume of coal annually to generate electricity. Many byproducts of combustion are generated when coal is burned. Bottom ash and a component known as fly ash consist of coal components which did not combust during the burning phase. Fly ash is light enough that it is carried up the flue with the flue gases, and ideally trapped in filters before reaching the environment. Bottom ash forms clinkers on the wall of the furnace, with the clinkers eventually falling to the bottom of the furnace.

Bottom ash is coarser than fly ash, with a sandy texture and particles ranging from about 0.1 mm to 50 mm in diameter. Physically bottom ash is typically grey to black in color and is quite angular. Bottom ash from dry-bottom boilers is generally dull black and porous in appearance. It typically has the consistency of coarse sand to gravel and higher carbon content than fly ash. Boiler slag is black and angular, and has a smooth, glassy appearance. Bottom ash can be used as a replacement for fine aggregate and is usually sufficiently well-graded in size to avoid the need for blending with other fine aggregates to meet gradation requirements. The use of bottom ash in normal strength concrete is a new dimension in concrete mix design and if applied on large scale would revolutionize the construction industry, by economizing the construction cost and decreasing the ash content.

Here the effects of bottom ash as fine aggregate in place of sand was used and compressive strength, split tensile strength, flexural strength, Modulus of elasticity were studied.Bottom ash is used as fine aggregate in the concrete by varying the percentage such as 25%, 50%, 75% and 100%. The mix of concrete selected is the standard mix M25 grade. Ordinary Portland cement of 53 grade conforming to IS: 12269-1987 is used for the present experimental investigation. It was observed that at 50% replacement, the results of compressive, split, flexural test approximately equal to or greater than the controlled concrete.

Keywords: Bottom Ash, concrete technology, strength and longevity of concrete, mechanical properties

Suggested Citation: Suggested Citation

Vijayan, Vishnu and V, ACHU and M. S., Riyana, Mechanical Strength of Concrete using Bottom Ash as Fine Aggregate (April 5, 2018). International Journal of Current Engineering And Scientific Research Volume 5-issue-4-2018, Available at SSRN: https://ssrn.com/abstract=3570084