Evaluating and improving the construction and demolition waste technical properties to use in road construction

The volume of Construction and Demolition Wastes is dramatically increasing around the world, mainly in urban areas, giving rise to environmental damage. In Tehran, producing 50,000 tons of the construction and demolition wastes (CDW) has made the lack of suitable sites for the disposal. This study aims were to evaluate the physical and mechanical properties of the CDW to possibly use in road construction, specifically as sub-base materials. To do so, after crushing the selected material from the disposal, a few important physical tests, including soil grading, Atterberg limits, modified compaction, California Bearing Ratio, and direct shear test were carried out to assess the obtained values with those exerted by standards in road construction. Furthermore, a series of cyclic plate load tests have been carried out to evaluate the effectiveness of geocell reinforcement on the bearing capacity of CDW materials. The results showed that the physical and mechanical properties of the studied CDW materials agreed with the majority of the standard criteria to be used as sub-base materials in road construction. The results of plate load tests revealed that cyclic bearing capacity of CDW backfills was 20-40% lower than that of standard material. However, geocell reinforcement could not only improve the CDW cyclic response approaching to natural aggregate (NA) response, but also boost bearing capacity ratio well above than one for all CDW materials.