Experimental Investigation on the Effect of Using Different Calcium Sources with Biogrouting on the Improvement of Poorly Graded Fine Sand

Abstract

In light of the cities' growth, it has now become necessary to establish infrastructure in areas that were previously deemed inappropriate.To improve the engineering characteristics of these problematic lands, many methods have been applied. Recently, an innovative and sustainable technique called Microbial Induced Calcite Precipitation has emerged for soil improvement. Many factors that affect the efficiency of this technique include the concentrations of bacteria solution, the concentrations, and the type of the chemical solutions, in addition to methods to introduce the bacteria and these chemical solutions to the soil, pH, etc.The objective of this study is to evaluate the performance of the Microbial Induced Calcite Precipitation as a technique to improve and enhance the very fine poorly graded sandy soils and expand knowledge about improving a loos sand by using the MICP technique. Furthermore, this study was carried out using six types of calcium sources in the cementation solution, two concentrations of cementation solution as well as two types of soils. This study shows that the use of low concentrations provides a greater improvement in the engineering properties of the treated soil. The pH values were not greatly affected by soil type or the type of cementation chemical solutions and their concentration. The samples with axial splitting had a lower unconfined compressive strength than that shown by the samples with shear fracture.