PSI - Issue 70

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

527

2.2 Experimental Setup Production of PET- SiO₂ geopolymer concrete followed a procedure which included mixing, casting, and curing specific steps. The process aimed to achieve uniformity along with best material results. 2.2.1 Mixing, casting, and slump test procedure Two minutes of mixing took place in a pan mixer between dry materials including fly ash and GGBS with aggregates. The addition of an alkaline activator solution (8M NaOH combined with sodium silicate) required gradual introduction for obtaining even reactivity across the mixture. Homogeneous distribution of PET- SiO₂ (0g, 4g, 5g, 6g per batch) was attained through mixing it with the other components for five minutes.According to the guidelines of IS 456:2000 the workability of the mixtures was tested through a slump measurement process. = _ − _ . The cone height measurement started at 300 mm as H_initial while H_final represents the recorded height after removing the cone. The measured slump values between 49.5 mm to 51 mm revealed suitable workability characteristics for structural applications.The concrete specimens received a cube shape of 100 x 100 x 100 mm for compression testing as well as beam specimens measuring 500 x 100 x 100 mm for flexural evaluation. Molds received vibration then underwent demolding after 24 hours before undergoing ambient curing for three, seven and twenty-eight days to achieve strength maturity. 2.2.2 Specimen preparation and curing

Fig. 2. Specimen Preparation and Curing Process (a) Preparation of concrete specimens in molds, (b) Curing process of specimens in a controlled environment, (c) Molding and compaction of PET-modified geopolymer concrete. Vibration methods were used to seal voids during casting of (100 × 100 × 100 mm) concrete cubes along with beams measuring (500 × 100 × 100 mm). The research samples received ambient curing duration extending up to 28 days along with 3 days and 7 days. 2.3 Testing Methods Multiple tests measured the mechanical characteristics alongside durability performance and microstructural aspect of PET- SiO₂ -integrated geopolymer concrete to evaluate its performance outcomes. Standard protocols for material testing provided standardized methods for evaluating concrete material strengths together with durability characteristics and microscopic features.