Microstructural characterization and reaction mechanism of home-brewed activator derived from eco-processed pozzolan for one-part geopolymer mortar
Document Type
Article
Publication Date
4-1-2025
Abstract
Anhydrous sodium-based commercial activators for one-part geopolymer (OGP) may cause eye damage, skin burns due to their corrosive nature, highly hygroscopic nature, high carbon footprint during production, high energy consumption, and cost. This research developed a home-brewed activator (HBA) from industrial/agrobased ash such as Eco-processed pozzolan (EPP) using an alkali fusion method. In the alkali fusion method, a mixture of sodium hydroxide (NaOH) powder and EPP at various weight ratios of 1, and 2 was calcinated in a muffle furnace at 300 degrees C and 500 degrees C for 1.5 and 3 h. Ground Granulated Blast Furnace Slag and Fly ash were used as binders for casting the OGP and two-part geopolymer (TGP) mortar specimens. From the X-ray diffraction (XRD) results, the main activator compounds such as thermonatrite (Na2CO3 & sdot;H2O), natrite (Na2CO3), calcite (CaCO3) and natrosilicate (Na2Si2O5) in HBA that initiate the polymerization reaction. The OGP mortar specimen produced a 28-day compressive strength of 50 MPa under the ambient curing regime with a NaOH/EPP ratio of 1, calcination temperature of 300 degrees C, and duration of 1.5 h. Both the OGP and TGP mortar specimens showed the presence of calcium aluminosilicate hydrate and calcium sodium aluminosilicate hydrate (C-A-S-H/C-N-A-S-H) geopolymeric gel. The carbon efficiency of OGP mortar specimens was found 70 % lower than that of TGP mortar specimens.
Keywords
Alkali-fusion method, Eco-processed pozzolan, Home-brewed activator, Reaction mechanism, carbon efficiency, One-part geopolymers
Divisions
sch_civ,CHEMISTRY,ocean
Funders
Ministry of Education, Malaysia (FRGS/1/2022/TK01/UM/02/4)
Publication Title
Construction and Building Materials
Volume
470
Publisher
Elsevier
Publisher Location
125 London Wall, London, ENGLAND