| dc.description.abstract | The modern construction industry demands sustainable material innovations to replace
Portland cement, which significantly contributes to CO₂ emissions. This study
investigates geopolymer mortar composed of Ground Granulated Blast Furnace Slag
(GGBFS) and Diatomite, activated using a combination of sodium hydroxide (NaOH)
and sodium silicate (Na₂SiO₃). The primary objective is to evaluate the influence of NaOH
molarity variations (8M, 10M, 12M, and 14M) and GGBFS:Diatomite composition ratios
(100:0, 90:10, 80:20, 70:30, 60:40, and 50:50) on the compressive strength and
microstructure of geopolymer mortar under ambient curing conditions. Cube specimens
measuring 5x5x5 cm were tested at 7, 14, and 28 days. The results showed that the 50:50
GGBFS:Diatomite ratio combined with 8M NaOH produced the highest compressive
strength, reaching 28.43 MPa at 28 days. In general, increasing the NaOH molarity
beyond 8M did not result in a significant improvement in strength and, in many cases,
reduced performance due to unstable gel formation, increased porosity, and a less
homogeneous microstructure. Ambient curing facilitated gradual strength development,
with 8M molarity proving to be the most effective in supporting optimal
geopolymerization and gel network formation. Microstructural analysis using Scanning
Electron Microscopy (SEM) revealed that under optimal conditions the geopolymer
mortar displayed a dense and cohesive gel structure, although some Diatomite particles
remained partially unreacted. These findings highlight the importance of balancing alkali
activator concentration and precursor composition under ambient curing conditions to
produce strong, stable, and environmentally sustainable geopolymer mortar. | en_US |
