*4.2. Effect of Lime*

Figure 7 shows the variations in (ksat) values with and without lime treatment for fiber-reinforced clay (FC and FM) without any curing. The addition of 6% lime causes an increase in ksat values in the order of 10−<sup>1</sup> cm/s for fiber-reinforced clay compared to that of an untreated case. The addition of lime leads to the aggregation of soil grains by Ca2+ ions, resulting in the formation of a flocculated structure [33,34]. The increased porosity of soil improves the connectivity of inter-aggregate pores and leads to an increase in ksat values [31]. A similar trend is observed for all the tested specimens; however, the rate of increase in ksat values is a function of fiber type, dosage, and length.

**Figure 7.** Variation of saturated hydraulic conductivity with lime content and confining pressure (**a**) 0.2%, 6mm; (**b**) 0.2%, 12mm; (**c**) 0.6%, 6mm; (**d**) 0.6%, 12mm.

#### *4.3. Effect of Curing Time*

The effect of the curing period on the ksat values of all samples with lime-treated expansive clay under different confining pressures is illustrated in Figure 8. Lime-treated soil reinforced with 0.2% FC (both 6 mm and 12 mm) exhibited a reduction in ksat values with an increase in curing period, as seen from Figure 8a. This is attributed to the fact that the cementitious compounds formed at a higher curing period fill the void spaces within the clay and the soil becomes less conductive [13]. At 0.6% FC, for 6 mm length of fibers, ksat values reduced marginally at a lower confining pressure (at 50 kPa), and a significant reduction is observed at higher confining pressure (at 400 kPa). Whereas, an increase in fiber length to 12 mm leads to an increase in ksat values up to 7 days of curing and thereafter reduced at the end of a 28-day curing period (Figure 8b). This might be due to an increase in the length of fiber creating more drainage paths during the first 7 days of curing. However, after a 28-day curing period, this effect is dominated by the formation of cementitious compounds, which reduces the ksat values with 12 mm fiber length.

**Figure 8.** Variation of ksat values with curing period and confining pressure (**a**) FC\_0.2% (**b**) FC\_0.6% (**c**) FM\_0.2% (**d**) FM\_0.6%.

Figure 8c,d depict the variations in ksat values with FM addition at various curing periods. The ksat values increased at the end of the 28-day curing period with a marginal reduction at 7 days compared with specimens without curing. Irrespective of the dosage and length of FM, the ksat values increased at all confining pressures.
