Utilization of perlite as a pozzolanic additive in soil stabilization with lime

Improvement of physical, hydraulic, mechanical and chemical properties of weak soils is named as soil stabilization. Perlite is a natural pozzolan due to its amorphous structure and high SiO2, Al2O3 and Fe2O3 contents. Perlite can be used a chemical stabilizer as other pozzolans. But perlite has pozzolanic properties but it possesses little or no cementitious ability due to lack of active CaO. Therefore, perlite requires a second additive that contains calcium for pozzolanic reactions in soil stabilization.In this study, stabilization with perlite and lime of a high plasticity clayey soil containing smectite group minerals such as montmorillonite and nontronite was investigated experimentally. For this purpose, test mixtures were prepared adding 0%, 10%, 20%, 30%, 40% and 50% of perlite and with 8% of lime (optimum lime ratio) and without lime. Geotechnical properties of the mixtures and change of these properties depending on perlite ratio and time were determined.The test results show that stabilization of the soil with combination of perlite and lime improves the geotechnical properties such as workability, plasticity, permeability, compressibility, strength and durability higher than those of perlite or lime alone. This experimental study unveils that SKP30 mixture containing 30% perlite and 8% lime is the optimum solution in the stabilization of this soil. The mathematical equations generated from regression analysis indicated that there are strong relations between geotechnical properties and variables of perlite ratio and time.