PSI - Issue 70

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

663

WFS could outperform geopolymer paver blocks without WFS in terms of performance. According to the IS Specifications, the pavers' compressive strength must be at least 30 MPa for roads with no traffic applications and 40 MPa for medium amount of traffic applications. The GPP blocks up to GPP_P45 meet this standard requirement, after which it decreases. 5.1.2. Flexural strength test After 28 days of curing, the flexural strength of GPP blocks was tested using a 40T compression testing machine, per IS 15658-2021. In a basic beam loading configuration, the GPP blocks were positioned halfway amongst supporting rollers, between 25mm rollers Fig. 5. Where, f is load at failure in ‘N′, l is the distance between the supporting rollers (i.e., 200 mm), b & t are the average width and thickness measured at fracture line. Fig. 6. depicts the paver blocks' 28-day flexural strength. As demonstrated, the addition of WFS considerably increase the GPP blocks flexural strength. The higher SiO 2 /Al2O 3 ratio improves the textural properties of geopolymer paste and strengthens the interfacial transition zone (ITZ), resulting in an increase in flexural strength by Nuaklong et al (2020). Furthermore, GPP blocks with WFS shows significantly higher flexural strength than GPP_P0.

Fig.5 Flexural strength test setup

Fig. 6. Flexural strength at 28 days of curing

Fig. 6. Shows flexural strength (MPa) comparisons between the Control Mix (CM) and Foundry Sand Replaced Blocks (FSRB) varied across MIX IDs. CM consistently showed 6.1 MPa. FSRB strengths were: 6.3 MPa (GPP_15), 5.8 MPa (GPP_30), 6.9 MPa (GPP_45), 5.6 MPa (GPP_60), 4.8 MPa (GPP_75), and 3.9 MPa (GPP_100). 5.1.3. Material hardness against abrasion The test adhered to IS 15658-2021. Trim Specimens measuring 70 mm × 70 mm x 50 mm and put on the testing apparatus following 28 days of ambient curing. 22 rev/min were produced in accordance with specifications. after a uniform load of 290 N was incorporated with the help of pressure stamp from the horizontal top surface. As an abrasion powder, the high refractive index aluminum powder, which contained roughly 95% aluminum oxide, had a specific gravity of 3.95 and a Moh's scale hardness of 9. Using a Vernier calliper to measure the initial and final thickness, the wear resistance of the GPP samples with and without WFS was ascertained. The results were related to IS 1237's maximum allowable limits of 3.5 – 4.0 mm for household wear applications and 2-2.5 mm for heavy movement. IS 15658-2021 was used to interpret volume loss in mm 3 per 5000 mm 2 . When the top surface of paver blocks is subjected to vehicle movements, wear resistance is crucial. The addition of WFS reduced volume loss, as indicated in Fig. 8. Abrasion tests revealed that WFS-based paver blocks observed a weight loss of 23.06 g, indicating enhanced durability under traffic loads. These benefits for WFS-incorporated GPP blocks may result from enhanced bonding with the aggregate particles and microstructure densification, which increases abrasion resistance. Also, the addition of fly ash to alkali-activated concrete improves abrasion resistance by strengthening the interfacial interface because the fine fly ash particles act as a micro-filler, increasing the binding between the aggregate and the gel by Mahdi at al (2022). The abrasion resistance, measured as weight loss percentage, was evaluated for GPP blocks without WFS and with WFS across various MIX IDs. GPP blocks without WFS