Geotechnical Characteristics of an Aerated Soil-Stabilizer Mixture as Backfill Material

Abstract

A considerable amount of effort has been made to find alternatives to conventional backfill materials in civil engineering works because conventional backfilling has disadvantages including insufficient compaction and shortages in the supply of natural materials. A flowable and lightweight fill material, specifically an aerated soil-stabilizer mixture (ASSM), is one such alternative to solve these problems. The geotechnical properties of ASSM with various water content levels were measured and analyzed to determine the optimal mixing ratio. The water content level controls the geotechnical characteristics of ASSM. ASSM mixed with a water content of 25 % yields the highest compressive and shear strengths and shows a suitable density and an allowable degree of vertical deformation. A series of laboratory tests was performed to estimate the geotechnical characteristics of the optimally mixed ASSM. The density, vertical deformation, compressive and shear strength, shear modulus, and coefficient of lateral earth pressure at rest (K-0) were measured. Its suitability as a backfill material was then investigated in comparisons with other backfill materials. ASSM shows better performance than typical backfill materials, as its strength, shear modulus, and linear threshold strain are higher, whereas its density and K-0 values are smaller.