Utilizing recycled materials and wastes like construction wastes and demolition reminders is onernof the justifiable solutions in terms of both cost minimizing and environmental concerns ofrntransportation infrastructure constructions. rnThe main objective of this study is to evaluate the suitability of the usage of ConstructionrnDemolition wastes of buildings in Addis Ababa to be fully or partially used as sub-base layer. rnThe scarcity and difficulty of providing construction materials like sub-base has been a challenge rnthat drags the road construction and the pavement industry not to be continued as expected. Onrnthe other hand, in Addis Ababa the extensive production of construction and demolition wasternand lack of disposition areas due to the overpopulation of the city have a great contribution onrnthe environmental pollution and it is also becoming a problem. rnIn this research, Construction Demolition Waste samples were collected from Addis Ababarnaround Mexico Area. Four samples were collected which are CDW1 (from Previous GomaKutebarncompound),rnCDW2rn(fromrnleftrnsidernofrnYobekrnBuilding),rnCDW3rn(fromrnthernbackrnofrnWabishebelernHotel)rnandrnCDW4rn(inrnfrontrnof Ministryrnof Health).rnrnrnGradation, Proctor Compaction, CBR, Atterberg Limits as well as LAA tests were conducted onrnall of the collected samples. However, all the samples pass the gradation requirement but couldrnnot pass the CBR requirement for subase material. Their Maximum Dry Densities (MDDs) arernalso lower than the expected MDD for subase. rnTherefore, in order to increase their densities and their bearing strength, it was tried to mix twornof the CDWs with Clay material with four proportions (10%, 20%, 30% and 40% by weight ofrnthe sample). The MDD and the CBR have shown a big increment when 20% to 30% of Clayrnmaterial is mixed with both of CDW samples and fulfill the CBR, Liquid Limit and Plasticityrnindex requirements for subase material in accordance to the ERA specification. rnHowever, all the CDW samples have higher LAA value than expected for subase material.rnTherefore, it was required to reduce the LAA value of the samples and it was tried to mix two ofrnthe samples with approved subase material with four proportions (10%, 20%, 30% and 40% by weight of the sample). In doing that, both of the samples fulfill all the ERA specificationrnrequirements and the LAA requirement as well. rnIn addition, it was tried to simulate the compaction during construction on site by proctorrncompaction and study the gradation curve after compaction. In order to do that, the samples leftrnfrom pure CDW1 and CDW1 + 20% Subase were taken and compacted by standard proctorrncompaction procedure and the gradation of pure CDW1 after compaction tends to cross the upperrnlimit allowable for subase material, whereas the CDW1 + 20% subase sampleâ€™s gradation lies inrnbetween. Therefore, CDWs + 20% subase pass all the laboratory test requirements in this rnresearch for subase material and 20% subase content is recommended as the optimum proportionrnof subase which is the minimum requirement. However, using more than 20% subase also fulfilrnall the requirements specified for subase material.