Publication: Influence of pofa treatment regimes, incorporation of eggshell ash, silica fume, and steel fiber on properties of upofa-based alkali activated mortar
| datacite.subject.fos | oecd::Engineering and technology::Civil engineering | |
| dc.contributor.author | Mohamed Omar Mohamed Mashri | |
| dc.date.accessioned | 2025-01-23T07:08:17Z | |
| dc.date.available | 2025-01-23T07:08:17Z | |
| dc.date.issued | 2023-09-01 | |
| dc.description.abstract | This research aims to develop alkali-activated mortars (AAMs) by utilizing the combination of palm oil fuel ash (POFA) with eggshell ash (ESA), silica fume powder (SFP), and steel fiber (SF). The strength performance and thermal stability of the synthesized AAMs were evaluated. At the same time, both the phase formation and microstructural characterization were also carried out. The research consists of four different stages. The first stage is about the investigation of the effects of POFA grinding parameters on the mechanical properties when synthesized as ground palm oil fuel ash (GPOFA)-based AAMs. The results revealed that the specific surface area of POFA was increased from 193 m2/kg to 1710 m2 /kg at the optimum milled quantity of 3 kg and milling period of 24 hrs at a speed of 945 rpm. The alkali-activated mortar based on the ultrafine particle of GPOFA produced a maximum compressive strength (57.5 MPa) at 28 days of curing. The superior results were linked to the formation of greater volume main binding phases consisting of a calcium silicate hydrate (CS- H) gel. The second stage investigated the effect of different temperatures and times on GPOFA and optimization of ultrafine palm oil fuel ash (UPOFA)-based geopolymer mortar in the production of geopolymer products. The UPOFA was prepared at four different temperatures (550 °C, 600 °C, 650 °C, 700 °C) at five different times (1, 2, 3, 4, 5 hr). The optimum calcination temperatures and heating time of the prepared UPOFA-based AAM mixture were 700 °C for 2 hrs which achieved a specific surface area of 1835 (m2/ kg) and a final particle size of 1.55 μm with residual carbon (0.056%). The superior final mechanical properties with compressive strength (88.45 MPa), were achieved at 28 days. The main binding phases were formed as a calcium silicate hydrate (C-S-H) type gel. The third stage is about the evaluation of the mechanical properties of UPOFA-based AAMs containing eggshell ash (ESA) and silica fume powder (SFP) via Taguchi method. The efficiency of UPOFA source material in the production of geopolymer products has been investigated via four factors, namely the NaOH concentration (moles), Na-silicate: NaOH ratio, ESA content, and silica fume powder (SFP) content, where each factor contains three different levels. The results INFLUENCE OF POFA TREATMENT REGIMES, INCORPORATION OF EGGSHELL ASH, SILICA FUME AND STEEL FIBER ON PROPERTIES OF UPOFA-BASED ALKALI ACTIVATED MORTAR showed that the optimum mixture consisting of 77 wt% UPOFA, 11.5 wt% ESA, and 11.5 wt% SFP achieved a high compressive strength of 125.4 MPa, after 28 days of curing. X-ray diffraction and Fourier transforms infrared spectroscopy (FTIR) analyses showed that the properties of the mixture were greatly improved with calcium silicate hydrate (C-S-H) gel as the main binding phases. The fourth stage is about the assessment of the effect of steel fibre inclusion on the thermal stability of POFA-based AAMs when exposed to different elevated temperatures (from 200 ℃ to 1000 ℃). The results showed through digital microscopy images that no changes in the steel fibbers’ surface and diameter in geopolymer matrix samples of GPOFA (sample M3Q1) and UPOFA (sample UP42) when exposed to these elevated temperatures. However, these results indicated their thermal resistance, unlike the triple mixture of UPOFA, ESA, and SFP (sample UES8), where there was a change of fibre diameter at 800°C and melting at 1000°C, in addition to the crystallization of the geopolymer matrix, resulting in a denser microstructure and higher compressive strength compared to samples of GPOFA and UPOFA. The effect of applying the oven curing regime was positive on the mechanical properties of geopolymer mortar at early ages, compared to the ambient curing. In this study, it is proven that both palm oil fuel ash (POFA) and eggshell (ES) as waste materials that are available in large quantities in Malaysia can be successfully employed as source material to produce high-quality geopolymer material and will facilitate to lessen environmental problems and extend the life of landfills as less quantity of wastes requiring disposal, besides promoting greener binder as an alternative to Portland cement with potentially superior properties and durability performance. | |
| dc.identifier.uri | https://erepo.usm.my/handle/123456789/20969 | |
| dc.language.iso | en | |
| dc.title | Influence of pofa treatment regimes, incorporation of eggshell ash, silica fume, and steel fiber on properties of upofa-based alkali activated mortar | |
| dc.type | Resource Types::text::thesis::doctoral thesis | |
| dspace.entity.type | Publication | |
| oairecerif.author.affiliation | Universiti Sains Malaysia |