Capillary Barrier System (CBS) is a cover system that can be used to control rainfall infiltration into a slope and improves the stability of the slope. The use of a capillary barrier system as part of a retaining structure for steep slopes has never been investigated. In this paper, the results of a study on the application of capillary barrier to a retaining structure using Geo-bags, named as a Geo-Barrier System (GBS) are presented. In addition, the use of recycled materials (e.g. recycled concrete aggregates and road asphalt) in forming the Geo-Barrier System is explored in this study as part of sustainable infrastructure development. Results of characterization of unsaturated properties of the recycled materials are also presented in this paper. The study shows that the Geo-Barrier System can be used effectively as a retaining structure and offers slope protection from rainfall-induced failures.