Effects of ground granulated blast furnace slag (GGBS) on the strength and swelling properties of lime-stabilized kaolinite in the presence of sulphates

Abstract

The use of ground granulated blast furnace slag (ggbs) is well established in many cement applications where it provides enhanced durability, including high resistance to chloride penetration, resistance to sulphate attack and protection against alkali silica reaction (ASR). The use of ggbs in soil stabilization is, however, still a novel process in the UK although it has been used in South Africa. This paper reports on efforts to extend the use of ggbs to highway and other foundation layers by determining the beneficial effect which it has on the reduction of expansion due to the presence of sulphates. The paper describes the results of laboratory tests on lime-stabilized kaolinite containing different levels of added sulphate to which different amounts of ggbs have been added. The tests determine the strength development of compacted cylinders, moist cured in a humid environment at 30~ and the linear expansion of these moist cured cylinders on soaking in water. The results illustrate that small additions of ggbs to sulphate containing clays which are stabilized with lime reduce substantially their expansion when exposed to water and have no significant deleterious effect on strength development.

Engineering Properties of Bentonite-Lime-Phosphogypsum Composite Reinforced with Treated Sisal Fibers

“…This increase in the dry unit weight and the optimum moisture content is attributed to the fact that the phosphogypsum fills up the void spaces left out after quick reaction of bentonite with lime resulting Base Exchange aggregation and flocculation. Similar observations were reported on lime-stabilized kaolinite in the presence of sulphates by [28]. A close examination of Table 2 further reveals that the decrease in the dry unit weight and increase in the optimum moisture content with the addition of sisal fiber to the bentonite-lime-phosphogypsum mix is observed.…”

Effect Of Coir Fibres On The Compaction And Unconfined Compressive Strength Of Bentonite-Lime-Gypsum Mixture

“…The effect of the addition of 4 % gypsum to the bentonite + 8 % lime is to produce a greater maximum dry unit weight and optimum moisture content. These observations are in agreement with Wild et al (1996), where the compaction behaviour was reported concerning lime-stabilized kaolinite in the presence of sulphates. Thus, from the above discussion, it is concluded that the dry unit weight and optimum moisture content of bentonite + 8 % lime increased with the addition of 4 % gypsum.…”

Lime stabilisation for earthworks: a UK perspective

“…Thus binder mix designs including products with rapidly available silica such as ggbs have been linked with the prevention of sulfate heave (Higgins, 2005). As an alternative hypothesis of how ggbs restricts sulfate heave, Wild et al (1996) suggested that the ggbs particles, which also contain aluminium, provide an alternative surface for ettringite nucleation. They proposed that ettringite growth extending from the surfaces of ggbs particles was nonexpansive, whereas if ettringite growth nucleated from the edgesite of a clay mineral this was associated with expansion (Wild et al, 1996).…”

“…As an alternative hypothesis of how ggbs restricts sulfate heave, Wild et al (1996) suggested that the ggbs particles, which also contain aluminium, provide an alternative surface for ettringite nucleation. They proposed that ettringite growth extending from the surfaces of ggbs particles was nonexpansive, whereas if ettringite growth nucleated from the edgesite of a clay mineral this was associated with expansion (Wild et al, 1996). It may be that the non-expansive nature of ettringite growth in this case was a function of the rapid supply of aluminate (rapidly dissolved from a relatively amorphous ggbs source) to combine with the other immediately available reactants, thus permitting the rapid formation of ettringite in the controlled manner described by Little et al (2010).…”