Evaluation of index and compaction properties of lateritic soils treated with quarry dust based geopolymer cement for subgrade purpose

Abstract

The effect of quarry dust based geopolymer cement on the index and compaction characteristics of soft problematic soils has been studied in the laboratory. The particular interest was on the geopolymer cement treatment of test problematic soils subgrade as hydraulically bound materials. In pavement foundation constructions, particular emphasis is always placed on how moisture suction and capillary actions affect the performance of the subgrade layer. Lateritic soils, which form the compacted foundation of pavements have the tendency to behave like plastics or liquids when in contact with moisture. These factors affect substantially the behavior and overtime performance, which is the durability of pavement subgrades. The primary aim of this research work was to adapt geopolymer cement synthesized from valorized solid waste materials (quarry dust and metallurgical slag). Laboratory experiments were used in this study. The test soils were observed to belong to A-2-6, A-2-7 and A-7 soils according to AASHTO classification, which are highly plastic and expansive. They are also of high clay content, a property which makes them unsuitable as moisture bound materials in foundations. The quarry dust based geopolymer cement was utilized at the rate of 10 to 150% by weight of dry soil in an increment of 10%. The test soils treatment protocol shows that the additive consistently improved the plasticity index and maximum dry density of the treated soils obtained at optimum moisture condition. The results have shown that the environmentally friendly cement derived from the valorization of solid waste has improved the properties of the compacted earth utilized under moisture bound environment. So, it stands as a good replacement for ordinary cement.