PSI - Issue 70

R. Ashwathi et al. / Procedia Structural Integrity 70 (2025) 698–705

703

Fig. 6. Comparison of early and final strength The strength ratio gradually increases till 20% and then it stabilizes. The finer particle size of the marble powder makes the matrix denser by filling the voids and promotes better load distribution (Afzal Basha et al., 2023; Shah Shashank, 2015). The minimal amounts of marble powder enhance the hydration process due to the presence of active calcium carbonate contributing towards the strength gain (Wang et al., 2022). The presence of marble powder in larger percentages disrupts the cohesion between materials. The insufficient cement paste reduces the formation of C S H gel contributing towards the strength and makes zone weaker (Afzal Basha et al., 2023; Shah Shashank, 2015). 5. Durability Test The long term performance of structure under various environmental condition is assessed through durability test. Enhancing durability is essential to ensure structural integrity, reduce the economic cost and environmental impact (Velumani et al., 2023), (Kenai et al., 2024). 5.1. Water absorption Test The test is conducted as per IS 1199:2018 to determine the amount of water that the concrete absorbs when it is submerged (André Jorge; Rosa, Alexandra; Pedro, D., 2014; Gameiro J.; da Silva, D. Correia, 2014). The rate of absorption indicates the degree of permeability (Aukour, 2009). The Fig. 7.a depicts the water absorption potential of concrete with varying percentage of marble powder at 28 days of curing. At 20%, it shows, better tendency towards performance. Water absorption = Weight of saturated specimen − Weight of dry specimen Weight of dry specimen! X100 5.2. Acid attack test The resistance of concrete against aggressive environment is evaluated in the test using sulphuric acid with pH of 2.1 (Rahimi Iman M.; Allahyari, Hamed; Habibi, T Samira, 2016). Acid degrades the materials responsible for hydration and results in loss of strength and structural integrity (Oza et al., 2022), (Afzal Basha et al., 2023). The strength retention of concrete before and after acid attack at 28 days of submersion is shown in the Fig. 7.b. The variation in the trend shows the percentage of strength loss subjected to acid attack. The conventional concrete shows 7.13% loss indicating vulnerability to acid attack. With the percentage of addition of marble powder at 5, 10, 15, 20, 25 and 30, the percentage loss is observed to be 6.40, 6.04, 5.61, 3.85, 6.40 and 8.36. The moderate vulnerability is observed at 20%.