Title:
Revolutionizing Ultra-High Performance Concrete: Unleashing Metakaolin and Diatomaceous Earth as Sustainable Fly Ash Alternatives
Author(s):
Yeluri
Publication:
Web Session
Volume:
ws_F23_Yeluri.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/29/2023
Abstract:
This study explores the use of Metakaolin (MK) and Diatomaceous Earth (DE) as fly ash alternatives in Ultra-high performance concrete (UHPC) to address fly ash shortage. Two UHPC mixtures fully replaced fly ash with MK and DE, with a water-to-cementitious materials ratio of 0.20 were identified. MK-modified UHPC exhibited a 10% increase in 28-day compressive strength, while DE-modified UHPC showed a 5% increase compared to the control mixture with fly ash. MK-modified UHPC demonstrated a similar modulus of rupture (MOR) to the control mixture, while DE-modified UHPC experienced a 10% decrease in MOR. Drying shrinkage measurements revealed a 22.6% reduction for MK-modified mixtures and a 30.7% reduction for DE-modified mixtures compared to the control mixture. All mixtures exhibited excellent chloride impermeability with surface resistivity values of 75 - 100 kO-cm. These findings highlight MK and DE as sustainable fly ash substitutes in UHPC, addressing the challenges of fly ash scarcity.