Journal Published Online: 10 January 2025
Volume 53, Issue 1

Mechanical and Microstructural Properties of Geopolymer Incorporated with Copper Slag Activated by Phosphoric Acid

CODEN: JTEVAB

Abstract

In this study, fly ash (FA), a kind of aluminosilicate precursor, is activated by phosphoric aid (H3PO4) to produce a silico-aluminophosphate geopolymer. This study aims to assess the viability of substituting M-sand with varying proportions, ranging from 0 % to 100 %, of copper slag in geopolymer mortar. The alkaline-activated geopolymer mortar was produced by using sodium hydroxide (NaOH) and sodium silicate. The phosphoric acid-activated geopolymer (PGP) samples were produced by changing parameters such as the liquid/solids (L/S) ratio, curing temperature, and molarity of H3PO4. The L/S ratios examined were 0.8, 0.9, and 1.0, whereas the molarities of H3PO4 employed were 8 M, 10 M, and 12 M. An assessment was conducted on the compressive strength, scanning electron microscope (SEM) examination, Fourier-transform infrared spectroscopy, X-ray diffraction, and energy dispersive X-ray analysis of PGP. The findings indicated a positive correlation between the compressive strength and the molarity, whereas a negative correlation was observed between the compressive strength and the L/S ratio. The highest compressive strength obtained was 41.1 MPa, which occurred when the optimum concentration of H3PO4 was 10 M. The formation of the P-O-Si-O-Al-O polymeric structure contributed to the strength of the phosphoric acid-based FA geopolymer. The SEM images demonstrated that the geopolymer samples containing 100 % copper slag and a L/S ratio of 0.9 exhibited a compact and uniform microstructure, resulting in enhanced strength characteristics.

Author Information

Sundaram, Kashini
Department of Civil Engineering, Thiagarajar College of Engineering, Madurai, Tamil Nadu, India
Dharmar, Brindha
Department of Civil Engineering, Thiagarajar College of Engineering, Madurai, Tamil Nadu, India
Pages: 17
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Stock #: JTE20240094
ISSN: 0090-3973
DOI: 10.1520/JTE20240094