## 3 Results and Discussion
### Creep Response from Micro Indentation Experiments  
The values for elastic modulus, hardness, creep modulus, and time characteristics from microindentation experiments are reported in this section. The indentation modulus of the wollastonite-reinforced hardened cement paste, based on Equation (2), is plotted as a function of fiber content in Figure 4a. Considering average values, a comparison between 0% and 10% wollastonite fibers reveals a slight linear increase in the modulus of elasticity. Beyond 10% the detrimental impact of binder loss in the cement becomes significant. Thus, a reduction in the modulus is observed. A similar trend is observed in the study by [PERSON] and [PERSON] where an optimal dosage of 11.5% cement replacement was reported [34; 35; 36]. This trend is also reflected in the hardness values shown in Figure 4b. Overall, to elucidate the statistical significance of the modulus and hardness values, [PERSON]'s HSD test was conducted on the data. While the differences in [PERSON]'s modulus values were not found to be significant (\(p\) = 0.096), the difference in hardness values with change in wollastonite fiber content was significant (\(p\) = 0.0414) at \(p\) < 0.05. The creep behavior of a material is represented by two main parameters: creep modulus and the time characteristic. Figure 5a shows the result of the creep response using Equation (8) for the wollastonite-reinforced cementitious composites. A similar trend to that of the elastic modulus and hardness values of the data is seen. Compared to the control sample, the 10% wollastonite replacement of cement has a 30% increase in creep response. This can be attributed to the crack-tolerance enhancing effect of the wollastonite fibers through micro-reinforcement as established elsewhere [39]. Figure 5b presents the creep response in terms of time characteristic (\(\tau\)(s)) which suggests how creep progresses throughout a structure's service life. This function, \(\tau\)(s), has been derived from the logarithmic behavior of \(\Delta h\)(\(t\)) in Equation (6). During dwell time, the creep modulus determines how much load the samples can withstand before this mechanism starts to cause high strain and deformation. Later, time characteristics dictate the creep curve response. As exemplified in Figure 5b, the material time characteristic does not increase with wollastonite fibers in the system. After a certain amount of replacement, this feature falls due to the binder replacement. Please note that the wider spread of the data is due to the highly heterogeneous nature of hardened cement paste at a small length scale, which is investigated using  
Figure 4: (**a**) The elastic modulus and (**b**) hardness for the system with increasing wollastonite content from the micro-indentation test. microindentation technique. This results in more variable data compared to macroscale experiments, which generally produce more consistent results. To shed more light on the statistical significance of the trends, [PERSON]'s HSD test was conducted on the creep modulus as well as time characteristic data. The creep modulus data showed very clear significant difference in results between various wollastonite fiber dosage cases with a \(p\) value of 0.000026. On the other hand, the results for time characteristic data showed insignificant difference with a much higher \(p\) value of 0.44. Figure 6 presents the inter-relationships between indentation modulus, hardness, creep modulus, and time characteristic. As can be seen in Figure 6a, the relationship between indentation modulus and creep modulus follows an increasing trend where an increase in indentation modulus in wollastonite-fiber-reinforced cementitious composites translates into an improvement in creep behavior. Here, a linear relationship is observed between Indentation Young's modulus and creep modulus with an R\({}^{2}\) value of 0.8. In terms of indentation hardness, however, such trend is not observed as can be seen in Figure 6b.