Modification clayey soil with geopolymer obtained with different waste material

The research presented in this thesis aims to experimentally investigate a potential use of geopolymer made various stabilizers of by-products (fly ash (FA-F, FA-C), slag (SL), glass powder (GP), metakaolin (MK), marble powder (MP), bottom ash (BA), rice husk ash (RHA), silica fume (SF)) to enhance mechanical performance of soil (clay) via deep mixing technique. For this purpose, strengths of geopolymer soilcrete specimens were determined by unconfined compressive strength (UCS) tests regarding curing times (7, 28, 90 and 365 days) comparing with Portland cement (PC). In addition, ultrasonic pulse velocity (UPV) tests, the effect of molarity (8M-16M), stress-strain behavior, failure modes and microstructure (SEM, EDX) of geopolymer specimens were examined. Moreover the rheological characteristic of geopolymer grout that used to enhance soil was conducted to understand the grout performances. Test results showed that UCS responses of geopolymer specimens compared to PC yield to i) a decreasing trend for FA-F, GP, MK, BA and MP+FA-F, ii) an increasing trend for FA-C, SL and combinations of SL (BA+SL, RHA+SL, SF+SL, MK+SL) favorably with a fewer proportions of stabilizers, and iii) higher increment due to long-term curing (90-day, 365-day). Despite some decrements, most of UCS values were found acceptable (>0.2MPa) for sufficient enhancement of soft clay. The UCS results were mostly confirmed by UPV performances. The geopolymer specimens were also found to present: i) a strong development for the alkaline concentrations 10M to 14M, ii) brittle behavior of stress-strain curves failed in axially splitting and near axial directions, and iii) intensity of silica peak (SEM, EDX) for strength responsibility of dense microstructure. The findings of the study relatively supported the usage of waste by-products in the production of geopolymer for potentially use in deep mixing. Thus, this research could be a basis for further effort. Reuse of by-products in this study was also beneficial for a clean environment.