## 3 Results and Discussion  
### Unconfined Compressive Strength  
Figure 3 depicts the compressive stress versus compressive strain behaviour of untreated and treated soil specimen at different curing periods, which are at 7, 28 and 90 days. Untreated and treated soil mixed with lime and alkaline activation with the inclusion of fibre were examined. It is clearly observed that the strength of the soil radically increased after 7 and 28 days curing period (Figure 3a,b) with 0.85 and 1.19 MPa (time) and 3.21 and 7.90 MPa (AA) for the treated soil respectively. However, the result continues to increase higher after a longer curing period (90 days) with 1.57 (time) and 10.96 MPa (AA) for both treated soil as shown in Figure 3c compared to untreated soil with the strength of 0.15, 0.20 and 0.21 MPa for all of the three curing periods. As reported by [39; 40], the improvement of the soil strength is also contributed to by the curing period and the addition of fibre. This is mainly due to the interaction of calcium chloride (time) and the ion in the KOH activator (AA) that allowed dissolution of the chemical and a higher degree of ionization to happen. Figure 3: Compressive stress vs. compressive strain for (**a**) 7 days, (**b**) 28 days and (**c**) 90 days. Figure 3a and Table 6 show that the specimens of untreated soil show higher ductile behaviour at a failure strain of 11.96% compared to treated soil specimen. As for the CLF and CFAF specimen, the failure strain shows 4.05% and 1.75%, respectively. This indicates that the ductility of the soil behaviour changes from brittle to ductile which can be explained by the sudden strength reduction that occurred after the peak axial stress value reached the maximum limit. According to [41], this occurrence due to the movement of the fibre tensile strength occurred upon loading and the following increase in the soil fibre composite strength. Meanwhile, for the 28 and 90 days curing period, both treated soil with inclusion fibre show decrement in brittleness which exhibited towards a plastic deformation and also small increment in failure strain for about 1.75% and 1.9% for 28 days and 3.17% and 4.19% for 90 days, both for CLF and CFAF, compared to 11% and 23.66% for untreated soil, respectively. This concludes that the inclusion of treated fibre in both treated soils improved soil strength compared to the untreated soil [17; 42]. Secant Modulus (E\({}_{\text{s}}\)) and Deformability Index (I\({}_{\text{D}}\))  
The result of secant modulus and deformability index that obtained from the unconfined compressive strength test (UCS) for the untreated and treated specimen after 7, 28 and 90 days curing period were tabulated as in Table 6. The secant modulus is a parameter in identifying the elasticity of the stiffness of soil. Secant modulus is also known as Young Modulus (Es) by [43; 44] were the compressive strength was divided towards the strain in the stress-strain curve (elastic part). The test is conducted in order to characterize the elasticity or stiffness of the soil. From the results, it can be seen that the specimen encounters an increasing trend for all of the specimens at 7 and 28 days curing periods. The increment of the secant modulus for both 7 and 28 days curing period for both stabilized soil with lime and alkaline activation are roughly 15.15 and 36.77 (lime) and 139.77 and 230.11 (alkaline activation) times greater than compared to the untreated soil specimens, respectively. The increment of the secant modulus for both additives with fibre inclusion associate with the past research that has been carried out by [39; 45]. Meanwhile, for the 90 days curing periods, the result shows decrement for the secant modulus with about 29% and 48% for both lime and alkaline activation compared to the 28 days curing periods, respectively. This might be due to the fact that the longer curing periods decrease the stiffness or elasticity of the soil for both treated soil with lime and alkaline activation.