PSI - Issue 70

Janani P.K. et al. / Procedia Structural Integrity 70 (2025) 525–532

526

Nomenclature

GPC - Geopolymer Concrete PET - Polyethylene Terephthalate SiO₂ - Silicon Dioxide (Silica) GGBS - Ground Granulated Blast Furnace Slag NaOH - Sodium Hydroxide Na₂SiO₃ - Sodium Silicate SEM - Scanning Electron Microscope EDX - Energy Dispersive X-ray FTIR - Fourier Transform Infrared Spectroscopy XRD - X-ray Diffraction

2. Materials and Methods A research study examined geopolymer concrete performance responses to PET- SiO₂ integration during its evaluation phase. This section details the materials used, mix design specifications, and preparation methodology to facilitate reproducibility. 2.1 Materials Used The composition of geopolymer concrete included fly ash as well as ground granulated blast furnace slag (GGBS), fine and coarse aggregates and an alkaline activator solution and PET- SiO₂ polymer additive. The fly ash served as the main aluminosilicate component in the binder system with GGBS added to quicken the early strength formation process. The 8M mixture of sodium hydroxide NaOH and sodium silicate Na₂SiO₃ established proper polymerization and structural stability in the alkaline activator solution. The project obtained its fine and coarse aggregates from sources that complied with IS 383-1970 standards in order to establish both proper packing density and mechanical strength. 2.1.1 PET- SiO₂ polymer additive The PET- SiO₂ polymer was synthesized by shredding PET waste, followed by acid hydrolysis with H₂SO₄/HNO₃ to create reactive oligomers. NaOH was used to stabilize pH, and nano- silica (SiO₂) particles enhanced the geopolymer matrix. The blend was thermally cured at 80°C for 12 hours to eliminate moisture and improve structural stability, resulting in higher mechanical strength and lower permeability.

Fig. 1. Preparation of PET-Silica Modified Geopolymer Concrete: (a) Setup of materials, (b) Mixing nano-silica with water, (c) Preparation of PET-silica gel, (d) Final PET-silica solution ready for use.)