PSI - Issue 70

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

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performed at 28 days determined the concrete's porosity level for durability evaluation. The sorptivity test measured water absorption rates by testing samples at specific time intervals starting from 1 minute up to 30 minutes. The sulphate attack test was executed at 28 days and 90 days to evaluate the concrete's resistance against sulphate degradation by measuring its strength and mass depletion. 4. Test findings 4.1. Effect of RHA and GSA on Workability The characterization of fresh concrete workability describes its ability to mix and place and compact without difficulty. The concrete requires easy handling and segregation prevention to achieve proper workability. The research employed Slump Test and Compaction Factor Test to measure workability in fresh concrete mixes containing RHA and GSA. Slump and compaction factor values of GSA-RHA mixes ranged from 70 to 80 mm and 0.86 to 0.91respctively as depicted in Fig.2. The experimental data shows that the slump and compaction factor values decrease steadily as RHA and GSA replace cement in the concrete mix. The workability of concrete mixes decreases because RHA and GSA ashes absorb a large amount of water from the mix which reduces available free water. The workability reduction matches earlier research on agro-waste ash concrete mixtures due to their small and irregular particle shapes (Wagan et al., 2019; Ganesan et al., 2008). The workable range of fresh concrete remained suitable for normal construction even after the workability reduction from RHA and GSA incorporation at moderate levels.

Fig.2. Test findings on slump and compaction factor

Table.3. Test findings on mechanical strength properties

Modulus of elasticity (GPa) 28 -days

Compressive strength (MPa)

Split tensile strength (MPa)

Flexural strength (MPa)

Mix ID

7-days 24.10 25.20 26.05 27.30 26.40 25.10

28-days

56-days

7-days

28-days

7-days

28-days

CC

32.23 34.85 36.10 37.90 36.40 35.00

33.90 38.75 40.05 43.23 41.36 37.24

1.90 2.10 2.25 2.42 2.46 2.28

2.85 2.90 3.12 3.50 3.31 3.20

3.15 3.20 3.25 3.34 3.27 3.18

4.62 4.70 5.10 5.25 5.00 4.68

27.8 28.6 30.1 32.1 29.4 28.2

R5G20 R10G15 R15G10 R20G5 R25G0