Work

Effects of HVFA with the addition of bottom ash, NaOH, and CaCO3 on self-compacting concrete (SCC) in tidal environments

Year: 2025

Type: article

Abstract: The study evaluates the impact of exposure to tidal zones over 240 days on the mechanical, microstructural, and durability properties of High Volume Fly Ash - Self Compacting Concrete (HVFA-SCC) for coastal infrastructure applications. The concrete mixture was designed with 60 % and 70 % fly ash (FA) as a replacement for cement, 20 % bottom ash (BA) as a substitute for natural fine aggregate (NFA), 0.05 molar sodium hydroxide (NaOH) as an activator, and 5 % calcium carbonate (CaCO 3 ). A comprehensive analysis of workability, flexural strength , displacement, compressive strength , microstructure, chloride ion concentration , and sulfate ion concentration was conducted. The FA content increased, and BA's addition significantly reduced the flow diameter. The combination of NaOH and CaCO 3 successfully modified the rheological properties of the mixture, meeting the SCC criteria. All HVFA-SCC variations demonstrated improved flexural and compressive strengths up to 240 days, while the control mixtures experienced reductions in the flexural capacity of 15.98 % and 14.44 %, respectively. Using FA contributed to a denser microstructure, enhancing durability and flexural toughness. Microstructural analysis shows that HVFA-SCC-70 +BA is more resistant to sulfate attack than the control concrete, characterized by dense C-A-S-H and uniform distribution of elements, despite visible micro-cracks on the surface. The combination of HVFA-SCC-70 +BA with NaOH and CaCO₃ significantly enhances the durability of the concrete in tidal zones, keeping ion concentrations below the threshold level, although it is not as effective as HVFA-SCC-70.

Source: Case Studies in Construction Materials

DOI: 10.1016/j.cscm.2025.e04593

Authors: Juandra Hartono, Purwanto, Januarti Jaya Ekaputri

Institutions: Institut Teknologi Sepuluh Nopember, Diponegoro University

Language: English

Topic: Concrete and Cement Materials Research

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Industry, innovation and infrastructure, Sustainable cities and communities

Open Access status: gold

Estimated APC paid: $2,660