Lakshmi Devi Nalamothu
Independent Researcher
India
Abstract
This study investigates the incorporation of Class F fly ash—sourced from coal combustion—into high-strength concrete mixtures to evaluate its effects on workability, compressive strength development, and durability parameters. Experimental mixes were cast with 0%, 10%, 20%, and 30% fly ash replacement of cement by mass. Slump, setting times, compressive strength at 7, 28, and 90 days, and chloride permeability were measured following BIS and ASTM standards current as of 2015. Statistical analysis (ANOVA) was performed to determine the significance of observed differences. Results indicate that up to 20% replacement yields comparable early strength and superior long-term strength and reduced permeability, while 30% replacement delays early strength gain beyond acceptable limits for high-strength applications. Five key research questions and identified research gaps guide the methodology. The study concludes with optimized mix recommendations and outlines potential for large-scale application of fly ash in sustainable, high-strength concrete production within the technology constraints up to 2016.
Keywords fly ash, high-strength concrete, compressive strength, durability, sustainability
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