PSI - Issue 70

V. Preethi et al. / Procedia Structural Integrity 70 (2025) 271–278

276

This inverse relationship between water content and flexural strength reflects the adverse impact of excessive water, which tends to weaken the cement matrix by increasing porosity and reducing bond strength between constituents. The 3D surface plot offers a spatial perspective of these interactions, highlighting a distinct peak where low water content and high GF dosage converge. The slope of the surface steeply declines as the water content increases or as the fiber content decreases, further emphasizing the sensitivity of flexural strength to these parameters.

3.3. Effect of Water and Cement content on Split Tensile strength of concrete

Fig. 4. Prediction results of Split Tensile Strength w.r.t. Water content and GF (%) The contour plot shown in Fig 4 indicates that split tensile strength increases with an increase in cement content and decrease in water content. Specifically, regions with cement content above 500 kg/m3 and water content below 180 kg/m3 exhibit higher strength values nearing to 6 MPa. This inverse relationship between water content and split tensile strength reflects the adverse impact of excessive water, which tends to weaken the cement matrix as observed for both compressive strength and flexural strength. The 3D surface plot offers a spatial perspective of these interactions, highlighting a distinct peak where low water content and high cement content converge. Additionally, the effect of GF dosage on the split tensile strength is very minimal as observed in case of compressive or flexural strength of concrete. 3.4. Effect of Cement content and Aspect ratio of GF on Compressive strength of concrete

Fig. 5. Prediction results of Compressive Strength w.r.t. Cement content and Aspect ratio In the contour plot shown in Fig 5, compressive strength values are mapped across varying levels of cement content (ranging from 318 to 600 kg/m3) and Aspect ratio of GF (from 800 to 2250). The colour gradient clearly shows that higher compressive strengths are achieved at higher cement contents and medium aspect ratio of GF. For instance, at a cement content of 600 kg/m3 and for an aspect ratio of 800 (lowest), the compressive strength is seen to reach up to 70 MPa. The 3D surface plot strengthens these observations, showing an increasing trend in compressive