Performance of fiber and industrial wastes in enhancing soil stabilization process compared to cement

In the present study, the effectiveness of a new combination of industrial wastes including calcium carbide residue (CCR) and silica-fume (SF) along with polypropylene fiber was investigated in comparison with cement for improving soft clays and increasing their durability. The results showed that in normal curing conditions, the use of CCR alone has little effect on the soil geo-mechanical performance. On the other hand, despite the initial favorable performance of cement, the W-D cycle with the failure of cement nanostructures can lead to the disturbance and even complete loss of the soil-bearing capacity. In contrast, the combination of CCR with SF had a prominent role in the stabilization process and a much lower deterioration potential was observed in the presence of the optimal ratio of CCR-SF. According to SEM-EDX and XRD analysis, expansion of solidification and reduction of voids were evaluated as the main factors of the more appropriate response of the recent system. Adding fiber to this series of samples had a significant effect on the growth of tensile strength, better absorption of energy, reduction of cracking ability, and as a result, improving the stability of the soil matrix. Following such a condition, the strength of the reinforced sample containing a 15% additive was found to be about 1.8 times the threshold allowed for successful stabilization. This can be attributed to the synergism of CCR-SF and fibers in improving the particle conjunction and reducing the access of voids for soil-water interaction. Based on the obtained results, the use of an optimal combination of CCR-SF with fiber can be recommended as a low-cost, environmentally friendly, and efficient option in improving the behavior of problematic soils and reducing their post-failure potential.