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Soft soils usually have shear strength values less than 200 kpa such as clay, silty clay, clayey sand, and soft organic clay. The presence of soft soils in engineering sites requires immediate remediation, which is either altering the site, or removing and replacing the existing soil. These solutions are not always applicable. Hence, other methods are needed which soil stabilization one of them. Soil stabilization is the modification of the physical and geotechnical properties of the weak, and soft soil either mechanically by compaction or chemically using chemical stabilizers. This paper presents a comprehensive review on the stabilization of soft soils by utilizing sustainable stabilizers which are waste and by-product materials such as ground granulated blast slag (GGBS), activated GGBS and cement kiln dust (CKD). These stabilizers are utilized as replacement to the traditional binders (cement and lime). The results indicate that GGBS alone gives only a slight enhancement because of the glassy phase of this material. Nevertheless, activation of GGBS by other materials improves the physical and geotechnical characteristics of soft soils substantially while the use of CKD gave remarkable enhancement to the soft soil characteristics. The physical properties are evaluated by Atterberg limits and compaction parameters, and the geotechnical characteristics are evaluated by the unconfined compressive strength (UCS) test. [ABSTRACT FROM AUTHOR]

This study aims, through experimental works, to develop a new and sustainable binder by reusing two waste materials, namely waste paper slag ash (WPSA) and granite dust (GD) to stabilize fine-grained soil and reduce the environmental impacts resulting from improper disposal in addition to reducing the use of cement and lime in soil stabilization. The soil utilized in this research was obtained from a site near 80th Street in Babylon Provence. The experimental works included sieve and hydrometer analysis, consistency limits, compaction test, and unconfined compression strength test at 3, 7, and 28 days of curing. Various binary blended binders derived from mixing of WPSA and GD at different proportions; 10:0, 7.5:2.5, 5:5, 2.5:7.5, and 0:10 were utilized. These binary blended binders were mixed with the virgin soil at 10% in the samples testing procedure. The results showed that the use of the mixture containing GD alone resulted in a reduction in the LL, PL, and PI, and when increase the percentage of WPSA in the mixture, LL and PL were increased while PI decreased. Moreover, the maximum dry density of the treated soil increased with the use of GD, however, it decreased significantly after the employing WPSA in the binder used. As per the outcomes of the compressive strength test, it was shown that the use of the mixture WPG0 that contains (100% WPSA) gave the highest compressive strength, which is equivalent to 14 times of that for the virgin soil after 28 days of curing. The strength then dropped with increasing the percentage of granite dust in the mixture. However, mixtures contained both of WPSA and GD exhibited acceptable compressive strength throughout the time of curing as the results indicated. [ABSTRACT FROM AUTHOR]