Experimental Investigation on the Feasibility of Using Geopolymer Products in Soil Nailing

Portland cement products are extensively used as parent materials in construction projects. However, the production and consumption of these products result in various environmental pollutants, including the emission of carbon dioxide gas and excessive water usage. Geopolymer products have emerged as a promising alternative to Portland cement and its products due to their diverse mechanical and chemical properties. Therefore, in this study, we aim to investigate the potential of geopolymer products as a replacement for Portland cement. To this end, the optimal mixing design was obtained by performing uniaxial compressive strength and flow table tests. Nailing is a commonly used method for stabilizing soil excavations and slopes, often involving the use of Portland cement as grout. Geopolymer is used as a potential replacement for cement grout in this system. Pullout tests were conducted to investigate the interaction between the soil and grout, considering the effect of curing conditions and environmental factors such as temperature, humidity, and overburden pressure for both the geopolymer and cement grouts. The results indicate that, in general, the pullout force of geopolymer samples is lower than that of cement samples. However, raising the temperature in geopolymer samples results in an increase in the pullout force, whereas an increase in temperature in cement samples leads to a decrease in pullout force. It can be concluded that geopolymer samples need to be modified by using an additive, such as sodium silicate, to achieve proper pullout force and suitable interlocking with soil grains.