Influence of the Non-Woven Geotextile (NWG) on the engineering properties of clayey-sand treated with copper slag-based geopolymer

Abstract This study investigated the potential effect of the non-woven geotextile reinforcing of the clayey sand treated with the copper slag (CS)-based geopolymer. To this end, preliminary tests such as standard compaction, P-wave velocity, pH, and Atterberg limits (Plasticity index) were conducted on variously treated samples. In addition, complementary tests including unconfined compressive strength (UCS), unconsolidated-undrained compression triaxial (UU), and scanning electron microscopy (SEM) analysis were performed on the reinforced samples. Furthermore, 0, 10, and 15% of CS and 0, 2, 4, 8, 12, and 16 M (M) NaOH concentrations were utilized in the investigation. The alkaline-activator solution (AAS) contained 70% of Na2SiO3 and 30% of NaOH, and the weight ratio of CS-ASS was one. Subsequently, the selected samples were reinforced with 0, 1, 2, and 3 non-woven geotextile (NWG) layers by various arrangements. The results indicated the acceptable increase in the peak, residual strength, and failure axial strain. The UU results further demonstrated the improvement in shear parameters. The negligible and significant increases in the internal friction angle and the undrained cohesion were evaluated, respectively. The microstructural analysis elaborated the three mechanisms of geotextile, which helps to improve the mechanical behaviour of the reinforced samples. These mechanisms include contact, bending action, and interweaving action; interweaving action plays a vital role in the strength enhancement of samples.