Geomechanical Behaviour of Uncemented Expanded Polystyrene (EPS) Beads–Clayey Soil Mixtures as Lightweight Fill

Lightweight fill can be advantageous in embankment construction for the purposes of reducing (i) bearing pressures on underlying soil foundation, (ii) destabilizing moments constructed earthen slopes, and (iii) earth acting behind retaining walls. This paper investigates merits/limitations particulate expanded polystyrene (EPS) beads mixed with clayey sand (CS) as lightweight fill, considering both geotechnical environmental perspectives. The bench-scale testing programme included standard Proctor (SP) compaction, California ratio (CBR), direct shear (sheardox), oedometer permeability performed two different gradation CS soils amended 0.5, 1.5 3.0 wt.% EPS, investigating nominal bead sizes equivalent to poorly-graded medium coarse sands. Compared unamended soils, compacted dry density substantially decreased increasing EPS content, from 2.09 t/m3 (0 EPS) low 0.33 3 (73 v.%) larger-sized beads. However, analyses test results investigated 50 400 kPa applied stress range, even 0.5 (21 caused a substantial mechanical failure, drastic decay CBR compressibility parameters studied soils. Given more detrimental cost leaving myriads separate forever among soil, it is concluded that approach adding producing uncemented lightened should not employed engineering practice.