Performance of One-Part Perlite-Based Geopolymer Concrete: Effects of Silica Modulus and Water-Binder Ratio

This study investigates the feasibility of producing geopolymer concrete using perlite through a one-part mixing method, focusing on the effects of silica modulus and the water-to-binder (w/b) ratio on performance. In the initial phase, the one-part geopolymer mix was compared to the conventional two-part mixing method based on compressive strength results. Subsequently, the influence of silica modulus (ranging from 0.50 to 0.80) on perlite-based geopolymer concretes (PGPC) produced via the one-part method was examined. Finally, the effect of the w/b ratio was analyzed for the mixture with the silica modulus that exhibited the highest mechanical performance. The compressive strength and microstructural properties [analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR)] of the PGPC were evaluated. The results demonstrated that PGPCs can be successfully produced using the one-part mixing method, with the compressive strength of one-part mixes surpassing that of two-part mixes. Specifically, the compressive strengths of the one-part mix method at 3, 7, and 28 days were 46.33%, 45.63%, and 33.24% higher, respectively, compared to those of the two-part method. For PGPCs produced with three different silica modulus values (0.50, 0.64, and 0.80), the 28-day compressive strengths were 27.43, 33.42, and 43.06 MPa, respectively. As the silica modulus increased, the workability of the mixtures decreased. Furthermore, increasing the w/b ratio from 0.43 to 0.50 resulted in a 38.47% reduction in compressive strength.