Microstructural Characterization of Fibric Peat Stabilized with Portland Cement and Silica Fume

• Published in: Materials Vol. 16; no. 1; p. 18
• Main Authors: Ahmad, Afnan, Sutanto, Muslich Hartadi, Ahmad, Niraku Rosmawati, Mohamad, Mazizah Ezdiani, Bujang, Mastura
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20.12.2022; MDPI
• Subjects: Analysis; Calcium aluminate; Calcium silicate hydrate; Carbon dioxide; Cement; Curing; Ettringite; fibric peat; Fourier transforms; Functional groups; Gas industry; Hydrates; Infrared analysis; Infrared spectroscopy; Mechanical properties; Microstructural analysis; microstructural characterization; Morphology; Peat; Peatlands; Photomicrographs; portland cement; Portland cements; Scanning electron microscopy; Silica; Silica fume; Soil stabilization; Stabilization; Thermal analysis; Thermogravimetric analysis; X-ray diffraction; X-ray fluorescence; X-ray spectroscopy; United Kingdom; Malaysia; India; microstructural characterization; silica fume; portland cement; stabilization; fibric peat
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16010018

Peat is a renowned problematic soil and needs stabilization to enhance its engineering properties. Silica fume (SF) and Ordinary Portland Cement (OPC) were extensively adopted to increase the mechanical properties of peat; however, their microstructural analysis is lacking. Investigated herein is the microstructural evolution caused by the OPC and SF implementation in peat soil stabilization. Initially, the compositional analysis (elements and oxides) of peat and binders was carried out via energy-dispersive X-ray (EDX) and X-ray fluorescence (XRF). Subsequently, the microstructural changes that occurred in the stabilized peat were examined through a series of microstructural analyses. The analysis includes scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and thermogravimetric analysis (TGA) for morphological, mineralogical, functional group analysis, and bond thermal analysis, respectively. The SEM micrographs evidence the transformation of loosely packed with large micropores of untreated peat into a compact dense peat matrix. This transformation is due to the formation of newly developed minerals, i.e., calcium hydrates (CH), calcium silicate hydrates (C-S-H), calcium aluminate hydrate (CAH), ettringite (Aft) caused by the pozzolanic reaction of binders as recorded by the XRD. Similarly, different molecular functional groups were found in the FTIR analysis with the incorporation of SF and OPC. Finally, the percentage of mass loss was assessed through TGA analysis revealing the decomposition of stabilized in the second and third stages.