Experimental determination of bonding performance between two layer roller compacted concrete pavement

In this study, the importance of roller compacted concrete (RCC) pavements in Turkey was evaluated. Additionally, taking into account the lack of research on this topic, various laboratory experiments were conducted using different products to measure the bond performance between two-layer RCC pavements and the best resulting bond material was used to build RCC pavements on a real road and its performance was assessed. Under same traffic, environmental and climatic factors and same bearing capacity of subgrade, RCC pavements were determined to be 33% to 38% more economical than their hot mix asphalt mixture (HMA) pavement counterparts. While revenue to cost ratio in all project durations and low density traffic volumes was 27,5%, this ratio increased to 43,5% for high density traffic volumes. In order to evaluate the bond performance, RCC layers were prepared mixing 300 kg cement with the optimum 5% water content and six different bond materials/processes were used for slant shear test. Then, four-point flexural strength test and depth penetration under water pressure test were conducted on beam specimens made with coating material containing silica fume, the best performing bonding material. Since compressive strength and flexural strength of the specimens prepared with the silica fume were similar to those of single layer specimen, it was seen that silica fume specimens could be used as bonding mixtures. On a real road, RCC pavements were applied as three sections: one layer, two-layer with silica fume bonding material and two-layer without any bonding material. After this application, slant shear test and four-point flexural strength test were conducted on the angular core and beam specimens. Based on the results of both tests, the sample containing silica fume bonding material was measured to reach 98% of the reference sample strength; whereas flexural strength of the two-layer RCC pavement with no bonding material included was only measured at 54% of the reference sample.