Experimental Study on Marl Soil Stabilization Using Natural Pozzolans

Due to the construction of more civil engineering structures on problematic soils, numerous ground improvement techniques such as soil stabilization have been developed. A wide variety of characteristics and engineering properties are shown by marl soil as a problematic soil; however, its stabilization has not been sufficiently investigated in the available literature. Thereby, this paper presents an experimental study of using natural pozzolans for stabilization of marl soil. Three types of natural pozzolans (volcanic ash) including Qizkorpi, Mamaloo, and Chichest near the city of Urmia, Iran, were used in this investigation. For this purpose, in addition to marl soil identification using X-ray fluorescence (XRF) analysis and its classification, the influence of three types of volcanic ash stabilizer contents of 5, 10, and 15% was evaluated through the maximum dry density (Standard Proctor Compaction Test) and optimum moisture content, Atterberg limits, unconfined compressive strength (UCS), and modulus of elasticity. Based on the results, satisfactory strength and durability characteristics were obtained by the mixtures of marl soils stabilized with three types of locally available volcanic ashes as stabilizers. The obtained results indicated that the increase in volcanic ash content and duration increases the efficiency of stabilized marl soil. In addition, the increase in the contents of volcanic ash decreases the expansion and ductility of marl soil. As a result, stabilized marl soil with volcanic ash can prepare the construction materials of houses and road infrastructures with low costs.