This study presents an evaluation of the effect of binary fly ash - lime mixture as a soil stabilizer on the bearing capacity of natural soils from Andean and Caribbean regions of Colombia. A comparative analysis of the bearing capacity effect on silty soil, sandy soil and clayey soil, which were added with hydrated Lime (L) and Ordinary Portland Cement (OPC) as a conventional stabilizers, and with an unconventional stabilizer product of binary mixture between fly ash of coal combustion and Ca(OH)2 (lime) called (FLM),. The comparison was made by correlative analysis between mechanical and microstructural behavior of soils added in experimental tracks 30 m long. Proctor compaction tests were used on each mixture combination to know the optimum moisture content and the maximum dry density. Unconfined compressive strength (UCS) at 7, 28, and 56 days of curing and 40 °C were used to evaluate the bearing capacity effect with different stabilizer doses from 0% to 24% by mass.