Mechanical and microstructural enhancement of clayey soils through recycled glass powder stabilization

In this paper, we use recycled glass powder (RGP) as a replacement of the soil to enhance the mechanical characteristics of the Mashhad clayey soil. For this purpose, a total of 60 unconfined compression tests and microstructural analyses including scanning electron microscopy (SEM) and x-ray diffraction (XRD) have been carried out on both of the unstabilized/stabilized RGP clayey soil specimens. The RGP contents used for replacing in the soil were 3% to 25% and the curing time were of 7 and 28 days, respectively. The results indicated that replacing RGP in clayey soil led to an increase in soil stiffness, unconfined compressive strength (UCS), maximum strain energy or energy absorption capacity (E_u), secant modulus (E₅₀), resilient modulus (M_R) and a decrease in the failure strain (ε_f) of the clayey soil mixture. The effect of increasing in the soil strength was more pronounced with RGP = 15% (optimum content) and more amount of curing times. The results obtained from the microstructural analysis were in full agreement with the findings obtained from UCS tests. The XRD tests indicated that the replacing of RGP = 15% with amorphous structure to the clays soil caused reduced the concentration of crystalline phases in the unstabilized soil specimens, leading to reduce in the intensity of the peaks. SEM results further emphasized that the microstructure of the clayey soil stabilized with RGP = 15% became more consolidated, with a noticeable reduction in the number and size of pores.