This study examined the geotechnical behavior of silty sand soil treated with cement and cement-mineral polymer through a series of static and dynamic tests. Uniaxial Compressive Strength (UCS) and Indirect Tensile Strength (ITS) tests were conducted on specimens with varying amounts of cement and polymer (ie, 5, 7 and 9% by weight). Based on the results of UCS and ITS tests, the optimal combination of 7% cement and 7% cement-polymer was selected. Subsequently, California Bearing Ratio (CBR), Freezing and Thawing (F-T), and Large-scale cyclic triaxial (LCT) tests were performed on the optimal combinations. The results indicate that the treatment improves UCS, stiffness, CBR, and durability. By adding the polymer, the maximum UCS Sof the te cement treated specimen can be achieved in a shorter curing period. Moreover, when exposed to F-T cycles, the cement-polymer specimen exhibited. improvements in weight loss (about 0.6%) as well as compressive and tensile strength (about 200 kPa) compared to the cement treated specimen. In the dynamic tests, the cement-polymer specimen outperformed the cement specimen at low to medium cyclic deviatoric stress levels (up to 275 kPa). However, at higher stress levels, this trend was reversed. This behavior can be attributed to the formation of microcracks and cracks due to growth of needle-shaped microcrystals in cement-polymer specimen. Additionally, the cement-polymer treated specimen experienced lower permanent deformation during cycling loading Overall, the polymer additive proves to be more effective in treating the base layer that withstands low and moderate stress levels, making it a suitable complement to a portion of cement

The present study investigated the dynamic and durability characteristics of silty-sand mixture treated with cement and mineral polymer. Tests were conducted on treated and untreated soils, including unconfined compressive strength, indirect tensile strength, durability, and large-scale cyclic triaxial tests. Additionally, to better understand the behavior of the treated soil, XRD, XRF, and SEM tests were performed. The results revealed that soil treatment significantly improved the compressive and tensile strength, durability and resilient modulus, while reducing permanent strain and damping ratio compared to untreated soil. Although adding polymer to the cement mixture increased the resilient modulus in the entire range of cyclic loading, beyond the cyclic axial stress of 275 kPa (according to AASHTO T307 standard) or the maximum applied stress of 400 kPa, the cement-polymer mixture exhibited an increase in permanent strain and damping ratio compared to the cement mixture. This was attributed to the creation of microcracks and breakdown in needle-shaped microcrystals within the cement-polymer mixture. Furthermore, when exposed to wetting and drying cycles, the cement-polymer mixture exhibited improvements in weight loss, volume change, compressive, and tensile strength reduction, with values of up to 6, 1.2, 1.5, and 3 times, respectively, when compared to the cement mixture. Consequently, soil treatment with the cement-polymer mixture demonstrated a relative advantage over the cement mixture in the normal stress range for the base layer (as defined by stress levels in AASHTO T307 standard). Nevertheless, for higher stress levels, the cement-polymer mixture did not maintain a relative advantage over the cement mixture.