PSI - Issue 70

S. Rajeshkumar et al. / Procedia Structural Integrity 70 (2025) 287–294

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and GSA blended as cement substitutes. The durability evaluation comprised sorptivity tests, water absorption (WA) measures, and sulphate attack assessment, as displayed in Table 4.

Table 4. Durability test results

Sorptivity, (mm/√min)

Sulphate attack

Water Absorption (%)

Mass Reduction (%)

Mix ID

Strength Degradation (%)

1 min

5 min 10 min 30 min

28 (days)

90 (days)

28 (days)

90(days)

CC

3.15 3.08 3.02 2.95 2.98 3.05

0.125 0.134 0.143 0.150 0.148 0.160

0.118 0.110 0.127 0.120 0.136 0.129 0.143 0.135 0.141 0.133 0.153 0.145

0.103 0.114 0.122 0.128 0.126 0.137

3.8 3.60 3.45 3.31 3.20 3.22

6.77 5.5 5.32 5.24 5.11 5.18

1.20 1.15 1.04 0.9 1.07 1.13

3.02 1.85 1.80 1.71 1.82 1.90

R5G20 R10G15 R15G10 R20G5 R25G0

The WB values are ranged from 2.95 to 3.08% as depicted in Fig.5. The study determined that concrete mix water absorption rates were lower than those of conventional concrete (CC). The mix R15G10 recorded the minimum water absorption at 2.95% whereas R5G20 absorbed 3.08% and R25G0 absorbed 3.05%. The water absorption decreased slightly because the fine RHA and GSA particles enhanced the packed density of concrete matrix structures. Concrete particles filled voids while reducing the pore structure which decreased the water absorption by concrete.

Fig.5. Water absorption test results

Fig.6. Sorptivity test results

The Sorptivity measurement reflecting water absorption by capillary action revealed minimally lower numbers for concrete containing RHA or GSA compared to CC mixtures and the test findings are exhibited in Fig.6. The sorptivity of CC was 0.125 mm/√min, while R25G0 exhibited the greatest sorptivity value of 0.160 mm/√min. Higher proportions of GSA in the mix lead to greater sorptivity because GSA possesses higher porosity than RHA. The positive effects of GSA addition on workability match its negative impact on concrete pore structure thus producing a slightly enhanced sorptivity level. The concrete mixes containing RHA and GSA exhibited superior sulphate resistance compared to typical control concrete. The R20G5 mix achieved the lowest strength loss of 5.11% at 90 days, while the other mixes had strength reductions between 5.11% and 6.77%, as illustrated in Fig. 7 & 8. The CC mix showed the maximum strength degradation of 6.77% while demonstrating the highest value. The R15G10 mix demonstrated the lowest mass loss of 1.71% to 3.02% when attacked with sulphate at 90 days of exposure. Pozzolanic interactions between RHA and GSA with the filler effect contribute to the diminished strength loss and lower mass reduction in the materials. The materials achieved two critical functions: they refined the pore structure and decreased material