Silty Clay Stabilization Using Metakaolin-Based Geopolymer Binder

Abstract

Geopolymer binders are adjudged as the latest wave of sustainable alkali-activated materials for soil stabilization due to their excellent bonding properties. This study applied metakaolin as a precursor for synthesizing the geopolymer binder by employing the mixture of quicklime and sodium bicarbonate as an alkali activator. The optimal mass mixing ratio of the alkali activator, metakaolin, and silty clay was determined by unconfined compression tests. The stabilization mechanisms of the geopolymer binder were measured by x-ray diffraction and Fourier transform infrared spectroscopy. The microstructural characteristics of the geopolymer-stabilized silty clay were observed by scanning electron microscopy with an energy dispersive x-ray spectroscopy and mercury intrusion porosimetry test for understanding the strengthening mechanism of the silty clay after the treatment. Results indicate that the optimal mass mixing ratio of the alkali activator, metakaolin, and silty clay is 1:2:17, and the unconfined compressive strength of the geopolymer-stabilized silty clay reaches the maximum value of 0.85 MPa with adding 15 wt% of the geopolymer binder. Diffraction patterns show an insufficient polymerization of the geopolymer binder in the silty clay in the early days but a rapid synthesis of aluminosilicate gels after that. The new asymmetrical stretching vibration peaks signified the formation of aluminosilicate networks and are responsible for the strength improvement of the silty clay. Microstructural analyses further confirm the formation of aluminosilicate gels and their positive impacts on the structure of the silty clay over curing age.

WITHDRAWN: Experimental investigation on Interrelation between hydraulic conductivity and Compressive strength of soft soil using metakaolin as stabilizer

“…Some soil has a hard stratum to work on; on the other hand, some have very poor properties to withstand the loading. Additionally, the productivity of building businesses is affected by the mineralogical qualities that speci c soils possess(T.Subramani 2015; Wang et al, 2021).…”

Stabilization of Fluidic Silty Sands with Cement and Steel Slag

“…Figure 10 presents the infrared spectrum evolution of the CSFSS over the curing age. It could be found that there was a strong absorption peak near 700 cm −1 during the early curing age, which was related to the bending vibration of Al-O [32]. An absorption peak near 630 cm −1 was also observed, which is commonly caused by the symmetrical vibration of zeolite-like atomic groups.…”

Geopolymers: The Green Alternative to Traditional Materials for Engineering Applications

“…Figure 15 indicates the impact of different contents of alkaline activator (AA) and MK in binders on the UCS of treated soil [140]. It shows a maximum strength at 7 days by 5% AA and 10% MK, with about 419 kPa as a mean value, then a decrease in strength afterwards.…”

“…Thus, the optimum content of GB should be 15%, while economically it would be adequate to select 12% as it shows a minor difference in strength from 15% GB. Figure 15 indicates the impact of different contents of alkaline activator (AA) and MK in binders on the UCS of treated soil [140]. It shows a maximum strength at 7 days by 5% AA and 10% MK, with about 419 kPa as a mean value, then a decrease in strength afterwards.…”