IMPROVEMENT OF EXPANSIVE SOIL BY ADDING GEOPOLYMER MATERIAl

Abstract

ABSTRACT Expansive soils are soils that have a tendency to undergo significant changes in volume due to variations in moisture content. The volume changes in expansive soils may result in heaving and cracking that lead to infrastructure damages worth several billions of dollars each year all over the world. In recent years, there has been a growing interest in chemical stabilization to treat the engineering characteristics of soil such as swelling, strength, and volume stability. It was used chemical material environmentally friendly, sustainable, and low-cost building materials that originate from various sources it's called Geopolymer. The present work's aim was to study the effect of adding five percentages of Metakaoline based-Geopolymer (MK) to expansive soil (0.3%,1%,2%, 4%, and 6%) with an activator ratio of 20% for the weight of dry soil at curing period (0day,7days, and14days). The expansive soil used in the present work was brought from the Governorate of Al-Anbar /Iraq. A number of laboratory tests have been carried out which were, including one-dimensional consolidation tests, shear strength tests, and physical tests. Additionally, Scanning Electron Microscope (SEM) and X-ray diffraction (XRD)tests were done. The swelling results showed that the addition of MK had an impact on the swelling reduction, which was reduced by about 91% with 4% MK at 14 curing days. Additionally, the optimum moisture content decreased from 23 to 18% with 4% Metakaolin, while the maximum dry density increased from 15.2 kN/m3 to 16.9 kN/m3. The peak value of unconfined compressive strength rises to (11) times the original soil for 4% MK with cured for 14 days. Moreover, the results of SEM and XRD illustrate the reaction of the clay with Geopolymer led IV to the production of binder particles and the create of cementitious particle from interactions. Finally, the stabilization of expansive soil with MK was a successful method and gave good results, it can be considered 4 % MK the best percentage of improvement expansive soil.