Experimental model of shallow foundation over treated expansive soil using fly ash-based geopolymer

In fact, constructing low-weight buildings over expansive soil is usually risky, directly influencing urban development. Therefore, this type of soil needs to improve before loading, and one of the new and sustainable methods is using geopolymer materials. This study uses fly ash-based geopolymer with different percentages (i.e., 0.5, 1, 2, 4, and 6%). After that, the 2% was selected and applied directly to the laboratory model to improve the surface layers of the soil. It can seem that, the soil transfers from high swelling potential to very low when using this percentage in both the free surface of soil and soil under load. The free swelling decreased from 13 to 0.3%, at the 6% geopolymer ratio, and the swelling pressure also reduced from 230 to 7 kPa at the same geopolymer ratio.