Expansive soil subgrade exhibits low volumetric stability due to moisture imbalance, rendering pavement serviceability loss. In the present study, an effort is made to improve the subgrade strength behavior of expansive soils by combining it with alkali activated binder (AAB) with chemically treated coir (TCF) and hemp fiber (THF). The research also compares the effectiveness of TCF and THF reinforced AAB soil by conducting a series of subgrade strength indicator tests at different slag/fly ash ratio (SFR). The influences of varying dosages of fibers and SFR in both fiber-reinforced AAB treated soil showed a significant improvement in CBR, tensile strength ratio, and flexural strength properties. It is observed that THF-AAB-soil shows higher interfacial bonding with strong interlocking density and tensile cracking resistance compared to TCF. Non-linear regression equations for CBR tests are proposed for both fibers reinforced AAB treated soil, which is chosen as a subgrade strength performance indicator. Experimental and model-predicted results of fiber-AAB-soil mixture show a satisfactory trend for low volume roads.

膨胀土路基由于水分不平衡而表现出低的体积稳定性，导致路面的可使用性损失。在本研究中，通过将碱活化粘合剂 (AAB) 与化学处理的椰壳纤维 (TCF) 和大麻纤维 (THF) 相结合，努力提高膨胀土的路基强度性能。该研究还通过在不同的矿渣/飞灰比 (SFR) 下进行一系列路基强度指标测试来比较 TCF 和 THF 增强 AAB 土壤的有效性。在两种纤维增强 AAB 处理的土壤中，不同剂量的纤维和 SFR 的影响显示出 CBR、抗拉强度比和抗弯强度性能的显着改善。观察到，与 TCF 相比，THF-AAB-soil 显示出更高的界面结合力，具有较强的联锁密度和抗拉伸开裂性。为两种纤维增强 AAB 处理的土壤提出了 CBR 测试的非线性回归方程，将其选作路基强度性能指标。纤维-AAB-土壤混合物的实验和模型预测结果显示出令人满意的低流量道路趋势。