Use of Alternative Materials in Sustainable Geotechnics: State of World Knowledge and Some Examples from Poland

Geotechnical engineering projects carried out within the framework of the low-emission econ-omy and the circular economy are the subject of many publications. Some of these studies pre-sent the use of various waste materials, as soil additives, for improving geomechanical behav-ior/properties. Many of these materials are eagerly used in geoengineering applications, pri-marily to strengthen weak subsoil, or as a base layer in road construction. Information on indi-vidual applications and types of these materials is scattered. For this reason, this article briefly discusses most of the major waste materials used for achieving weak soil improvement in ge-oengineering applications, and highlights pertinent bibliographic sources where relevant details can be found. The presented list includes waste from mines, thermal processes, end-of-life car tires, chemical processes (artificial/synthetic fibers), and from construction, renovation and demolition works of existing buildings and road infrastructure. In addition to the positive im-pact of using waste instead of natural and raw materials, the paper encourages the reader to ponder whether the waste used really meets the criteria for ecological solutions.