Use of recycled concrete waste from urban transformation process as subbase materials in pavement construction

According to the urban renewal investigation started in 2012 in our country, environmental problems and high quantity of construction and debris waste increased. In addition, natural resources have also started to consume. For this reason, waste materials should be recycled as an alternative raw material source. Urban renewal method does not only help to conserve the natural resources, it also benefits the country's' economy and environmental effects. In this study, the usability of concrete debris converted to aggregate in the base-layer of flexible pavement was investigated. Limestone aggregate which was used as natural aggregate and concrete waste aggregate (BBA) were tested according to Turkish Highway Construction Standard (KTŞ) and conducted tests results were compared with the specification limits. In the first part of this study, the importance, purpose and scope of the this research were explained, while flexible pavement layers were discussed in the second part. Then the conducted researches on the use of recycling materials were investigated. In the third part of this investigation, aggregate tests were performed to determine the physical and mechanical properties of BAA and limestone aggregate (KA). Then, sub-base design was made with KA material and BBA was added to the mixture with the same granulometry as KA in different rates. Modified Proctor, CBR and freeze-thaw tests were performed on these mixtures and obtained results were compared with the KTŞ 2013 specification limits. Finally, after the evaluating of test results discussed in the fourth part of this investigation, it may be concluded that BBA can be used in the sub-base layer with the specified ratios.