Kaolin is widely known to possess high compressibility and low strength that leads to infrastructure collapse. Nevertheless, it is crucial to produce soil with such properties because of its immense demand by the infrastructure section amidst the rapidly growing population in Malaysia. The soil must be stabilised before construction so that several critical characteristics can be enhanced. Soil stabilisation finds extensive use in the treatment of the subgrade layers concerning road building. The objective of the study is to ascertain how the physical characteristics of kaolin change upon treatment with different concentrations of granulated ground furnaces blast slag (GGBS); changes in particle size and compaction properties are some areas of interest. Furthermore, the study assesses how a specific quantity of GGBS may be used for enhancing kaolin strength when it is cured for up to 28 days. Seven days curing time for 20% and 25% GGBS-kaolin blend leads to strength enhancement that exceeds the subgrade layer requirement. Considering the case of 25% GGBS-kaolin blend cured for 28 days, the maximum strength was determined to be 8.4 MPa. The inclusion of GGBS leads to changes in crystal phase and structure which can be observed using microstructure analysis
