Mechanical Properties of Lightweight Cellular Concrete for Geotechnical Applications

Abstract

Lightweight cellular concrete provides many advantages in geotechnical applications, however, its use has been limited because of a lack of understanding of its engineering properties. In this study, laboratory soil tests were conducted on lightweight cellular concrete having four different densities, and shear strength parameters, coefficients of permeability, and at-rest earth pressure coefficients were measured. Unconfined compressive strength and as undrained strength properties (total friction angle and cohesion intercept) of partially saturated materials were found to be dependent on the density of the lightweight cellular concrete specimen. However, the effective friction angle and cohesion intercept of the saturated materials were independent of the test unit weight over the range of stresses tested. The effective friction angle and cohesion values of the lightweight cellular concrete materials, determined from direct simple shear tests, were 35° and 36 kPa, respectively. Back-pressure saturated samples from isotropically consolidated drained and isotropically consolidated undrained triaxial tests yielded an effective friction angle of 34° and a cohesion intercept of 78 kPa, similar to the results obtained from the constant-volume direct simple shear tests. The at-rest earth pressure coefficient was found to range between 0.2 and 0.5, while Poisson’s ratio for these materials was observed to range between 0.20 and 0.30. Recommendations are made for appropriate geotechnical engineering properties for the use of lightweight cellular concrete materials in earth-retaining structures.