PSI - Issue 68

Eyad Shahin et al. / Procedia Structural Integrity 68 (2025) 238–244 E. Shahin et al. / Structural Integrity Procedia 00 (2025) 000–000

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Table 4. Summary of tensile peak stress and its corresponding strain of different mixes.

First crack strength (MPa)

Average first crack strength (MPa)

Average tensile stress (MPa)

Average peak strain (%)

Ultimate tensile stress (MPa)

Ultimate tensile strain (%)

Mix No.

Samples

G30-1-T25 G30-2-T25 G30-3-T25 G30-4-T25 G30-5-T25 G60-1-T25 G60-2-T25 G60-3-T25 G60-4-T25 G90-1-T25 G90-2-T25 G90-3-T25 G90-4-T25

7.89 9.06 8.75 6.08 7.08 7.90 7.24 5.21 7.12 5.93 6.93 5.07 6.42

2.517

4.3 3.7 4.1 2.8 3.1 4.1 3.9 3.4 3.2 3.9 3.5 3.1 2.9

1.78

G30

0.403 1.265 0.111

7.772

1.215

3.60

7.22 3.83 1.20 3.09

G60

6.868

3.835

3.65

1.082 1.644 1.665 1.481

G90

6.088

1.468

3.35

3.2. Quasi-static compressive behavior of GGBS-ECC At 28 days, the ECC mix with 30% GGBS replacement reached a compressive strength of 67.2 MPa, while the mix with 90% GGBS replacement achieved 62.9 MPa. These compressive strengths are higher than those reported for ECC made with fly ash in previous studies by Holschemacher et al. (2010) and Li et al. (2001). This improvement can be attributed to the higher reactivity of GGBS, which leads to enhanced secondary hydration reactions and a denser matrix compared to fly ash-ECC. In addition, GGBS reduces the permeability of the composite, thereby increasing resistance to harmful chemical attacks in aggressive environments. The pozzolanic activity of GGBS significantly contributes to long-term strength gain, further improving performance over time. The finer particle size of GGBS also contributes to a more refined pore structure, increasing the overall strength and durability. While compressive strength generally decreased as the GGBS content increased, the mix with 60% GGBS replacement demonstrated an exception by achieving the highest compressive strength of 72.5 MPa. This indicates that the GGBS content plays a critical role in optimizing the compressive strength, and 60% GGBS appears to be the optimal replacement level in this case. Beyond this point, the compressive strength showed a decline as GGBS content further increased.

Table 5. Summary of compressive strength and density of cubes of different mixes.

Cube Samples

Avg. Density (Kg/m3)

Peak Load (kN)

Mass (grams)

Stress (MPa)

Density (Kg/m3)

Avg. stress (MPa)

Mix No.

G30-1-T25 G30-2-T25 G30-3-T25 G60-1-T25 G60-2-T25 G60-3-T25 G90-1-T25 G90-2-T25 G90-3-T25

159 163 182 172 191 181 161 160 151

261.5 267.5 256.5 250.5 252.0 256.0 255.0 258.0 265.5

4.3 3.7 4.1 4.1 3.9 3.4 3.9 3.5 3.1

2092 2140 2052 2004 2016 2048 2040 2064 2124

G30

67.2

2095

G60

72.5

2023

G90

62.9

2076