U Karst
Vol. 9 No. 2 (2025): NOVEMBER

The Efficacy of Type F Fly Ash from Paiton Power Plant on the Compressive Strength of Concrete

Wahyudi, Thesalonika Octaviana (Unknown)
Kartini, Wahyu (Unknown)
Puspitasari, Nia Dwi (Unknown)



Article Info

Publish Date
09 Feb 2026

Abstract

Portland cement is the primary binder in concrete and plays a crucial role in defining its structural performance. However, its production contributes approximately 7% of global carbon dioxide emissions, necessitating sustainable alternative materials. One potential material is Type F fly ash derived from coal combustion waste in steam power plants. This study aims to evaluate the effectiveness of Type F fly ash from the Paiton Power Plant as a sustainable cement replacement material in concrete based on compressive strength performance. Fly ash was activated using an alkaline solution consisting of NaOH and Na₂SiO₃ with a ratio of 1:2.5, where the NaOH concentration was maintained at 10 M. Two water–cement ratios (W/C) of 0.45 and 0.55 were employed to investigate their influence on workability and compressive strength. Cylindrical specimens were tested at 28 days with fly ash replacement levels of 0%, 80%, 90%, and 100% by weight of cement. The results indicate that increasing fly ash content significantly enhances compressive strength. The optimal performance was achieved with 100% fly ash replacement, yielding a compressive strength of 48.48 MPa or an increase of 102.4% compared to conventional concrete. This performance is attributed to the high silica content of Type F fly ash, which promotes the formation of dense N-A-S-H gel through alkaline activation, resulting in a more compact and less porous microstructure. These findings demonstrate that Type F fly ash from the Paiton Power Plant can effectively function as a primary binder, offering a sustainable alternative for high-performance concrete production.

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Journal Info

Abbrev

ukarst

Publisher

Subject

Civil Engineering, Building, Construction & Architecture

Description

U KaRsT is a journal of the civil engineering research the University of Kadiri published twice a year in April and November. First published in April 2017. U KaRsT already has both ISSN printed and online, for ISSN (Print) is 2579-4620, and ISSN (Online) is ...