Clayey Soil Strength Improvement by Using Alkali Activated Slag Reinforcing

Abstract

There are many studies related to using alkali activated binders for the improvement of clayey soil mechanical properties. In this study, alkali activated slag (AAS) for the improvement of clayey soil strength was used and it reinforced the clay. This paper presents results of an investigation on the utilization of ground-granulated blast-furnace slag in the reinforcement of clay soils. Therefore, significant cost savings could be achieved by using alkali activated slag as binding material. These samples were analyzed by X-Ray fluorescence analysis (XRF), X-Ray diffraction (XRD), scanning electron microscopy (SEM) and strength tests after the curing. The clay samples reinforced with AAS showed higher shear stress, cohesion and internal friction angle compared with the samples without reinforcement. The highest shear strength was achieved by using the highest amount of AAS (30%). This shear stress of the unreinforced clay samples could be increased from 63.2 to 137.4 kPa (117.4%) and from 123.2 to 257.4 kPa (108.9%) when the normal stress value of 100 and 500 kPa was used, respectively. The increase in shear strength is closely related to the compact contact zone between AAS and clay. Moreover, the new formed cementitious compounds of AAS had a positive influence on the shear strength of samples as well.

Why geopolymers and alkali‐activated materials are key components of a sustainable world: A perspective contribution

“…In some cases, a mix design can be so robust that comparably large variations of the precursor properties still provide satisfactory outputs; for example, in applications with minimal requirements such as earth embankments or substrate layers. [61][62][63] Key parts of the technical requirements also refer to safety during use and after the end of the product life cycle. This aspect is usually addressed by determining the leaching of heavy metals and selected organic compounds; the latter is usually not relevant to AAMs.…”

Geopolymers as Alternative Sustainable Binders for Stabilisation of Clays—A Review

“…The use of GGBS in geopolymerisation for soil stabilisation has attracted the attention of many researchers. The study by [57] considered the performance of GGBS with the addition of phosphogypsum which is largely composed of CaO and SiO 3 , to increase synthesis of the geopolymer. Results of triaxial tests conducted on the stabilised clay samples showed over 100% shear strength gain over untreated samples.…”

Behaviour and Microstructural Characteristics of Lime-GGBS-Treated Kaolin Clay Contaminated with Gypsum

“…Furthermore, like other industrial and agricultural residues, the use of GGBS lessens the already heightened concerns of increasing landfill wastes synonymous with the production of the more common traditional calcium-based stabilisers (CBS). In addition, the use of GGBS is known to be advantageous as an eco-friendlier stabiliser with lower carbon-footprint than CBS [ 40 , 41 , 42 , 43 ].…”