PSI - Issue 70

Hariharan kannan et al. / Procedia Structural Integrity 70 (2025) 658–665

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for 24 hours. After that it was demoulded and kept in oven maintaining 90°C temperature for 24 hours. Later the completion of heat curing process the blocks were kept at indoor environment (20°C to 25°C) Fig. 2.

Fig 1. Preparation of alkaline solution

Fig 2. Casted samples

5. Results and discussion 5.1. Hardened properties test

After 24 hours of heat curing at 90°C degrees Celsius, the GPP blocks was tested for flexural strength, abrasion resistance, and compressive strength at 28 days. The heat captivated is crucial to the chemical reaction because geopolymer condensation is an endothermic reaction, which quickens the toughening and strengthening of the geopolymer mix by Pavithra et al (2016). Three specimens were casted for each mix and the average were considered.

Fig.3. Compressive strength test setup

Fig. 4. Compressive strength of pavers at 28 days

5.1.1. Strength evaluation under compression load The IS 15658-2021 specification was used to estimate the load under compression of GPP blocks. A digitally supplied pressure gauge and compression testing apparatus with a 2000 kN maximum capacity was used. The specimen is placed unconventionally amongst the bearing plates along the measured plan area. Apply the load at a rate of 0.018 kN/mm2/minutes and then it was gradually increased till the breaking load. The compressive strength was examined by diving the load and the calculated plan area. A paver block's compressive strength test setup is given away in Fig. 3. Fig. 4. depicts control Mix compression strength is consistently 52.4 MPa across all GPP mixes (15, 30, 45, 60, 75, 100). Foundry Sand Replaced Blocks (FSRB) compression strengths are 45.5 MPa (GPP_15), 48.6 MPa (GPP_30), 54.8 MPa (GPP_45), 39.6 MPa (GPP_60), 33.4 MPa (GPP_75), and 26.7 MPa (GPP_100). As can be seen, adding WFS boosted compressive strength marginally in selected molar ratio. At moderate exposure settings (46 ⁰C), Geopolymer blends, with WFS and without it, achieved appropriate compressive strength, indicating successful dissolution of aluminosilicate particles across all mixes. Additionally, the compressive strength of the GPP blocks with WFS was noticeably more than that of GPP_P0. For instance, after 28 days, the compressive strength of the GPP_P45 mix was 4.37% higher than that of the GPP_P0 mix. This demonstrates unequivocally how GPP blocks with