State-of-the-art review on efficacy of xanthan gum and guar gum inclusion on the engineering behavior of soils

Soil amelioration is a challenging task in bulk civil engineering applications such as embankment slopes, landfill liner, pavement subgrade, retaining wall back fill. The conventional chemical stabilization techniques (i.e., cement, calcium hydroxide, sodium chloride, calcium chloride, etc.) inherently suffer from associated carbon emissions during their production stages. With the advent of biopolymers derived from natural sources having low embodied energy levels, they can replace conventional stabilizers. The current review article highlights the significant properties of two such biopolymers, i.e., xanthan gum (XG) and guar gum (GG), and their innate potential in stabilizing different soil types including mine tailings. The issues arising with wet and dry mixing of these biopolymers and suggested measures have been critically addressed. The degradation characteristics of biopolymers, which limit their use for bulk civil engineering applications, have been critically discussed, and the potential solutions to overcome durability issues are suggested. Future applications of these biopolymers in geoenvironmental engineering relying on the metal encapsulation properties are discussed in detail. It is believed that the selected biopolymers in this review are renewable, sustainable and remarkable materials with low embodied energy levels and low carbon footprint values compared to existing conventional stabilizers.