Consistency of Fly Ash Quality in Making High Volume Fly Ash Concrete

Antoni, and WIDIANTO, ALVIN KRISNANTA and WIRANEGARA, JERRY LAKSMANA and Hardjito, Djwantoro (2016) Consistency of Fly Ash Quality in Making High Volume Fly Ash Concrete. In: SRIWIJAYA INTERNATIONAL CONFERENCE ON ENGINEERING, SCIENCE & TECHNOLOGY (SICEST2016), 10-11-2016 - 10-11-2016, Bangka Island - Indonesia.

	PDF Download (307Kb)
	PDF Download (489Kb)

Abstract

Fly ash is the by-product of coal burning process, which is widely used as a substitute for cement material. The advantages of using fly ash in concrete including the improvement of the workability and reducing bleeding and segregation. The problem that is often encountered when using fly ash is the uncertainly of the fly ash quality. The quality is influenced by the coal origin, burning techniques, mineral content, and capturing method. In this study, the consistency of fly ash from one power plant source was investigated in making a high volume fly ash (HVFA) mortar. Variations in the fly ash can be detected by applying rapid indicators that is suggested in this paper i.e. the pH value of the fly ash in aqueous solution and the percentage of fly ash particles passing sieve #325. The fly ash replacement ratio was varied from 10% to 60% of cement mass. The results showed that there are large variation in the chemical content of the fly ash shown by the variation of the pH value, while only slight variation in the physical properties of the fly ash, i.e. the particle size and shape. Superplasticizer demand for the same flow was reduced with the increase of fly ash content, and optimum fly ash replacement ratio for optimum strength could varied between fly ash from different sampling periods. The compressive strength could reach the same as control specimens for replacement ratio of 20 to 30% for some fly ash, and mortar compressive strength of 42 MPa still achievable with replacement ratio of 50%.

Actions (login required)