Improvement performance of grouting mortar with fly ash and silica fume for semi-rigid pavements

In our globalizing world, traffic volume and load are increasing in line with urban developments. These increases bring some problems such as increased road maintenance costs and shorter life span of the roads. In addition, the increase cost of asphalt, reveals the necessity of an alternative road pavement type. Semi-Rigid Pavement (SRP) type roads, also known as Semi-Flexible Pavement in the literature, which is an alternative road pavement design to other pavement types. SRP is constructed by placing the fluid mortar which is developed for SRP to %25-30 air void asphalt pavement. In this thesis, the effects of fly ash and silica fume on the CEM I 42.5 R type cementitious filling mortar that filled the porous asphalt during the construction of SRP were investigated by experimental studies. Mortars, which is designed with this waste material pozzolans, were subjected to bleeding and fluidity tests, compressive and bending strength and drying shrinkage tests were applied to the samples which is removed from the moulds. First, mortar with optimum mixing ratios was obtained by using only cement, aggregate, water, and superplasticizer as control sample. Then, the optimum mixing ratios of the mortars formed by substituting silica fume and fly ash, which are artificial pozzolans at different rates, were determined by the Response Surface Method. SRP was formed by placing the determined optimum filling mortars into the porous asphalt in large mould sizes. Core samples were taken from the formed SRP. The obtained samples were subjected to Marshall stability, indirect-tensile strength, compressive strength, Cantabro and freeze-thaw tests. Based on all the obtained results, the optimum silica fume ratio was determined as 5.9%, as it increases the advanced age strength and resistance to cold weather effects and reduces the susceptibility to moisture damage. On the other hand, the optimum fly ash rate was determined as 12.5%, as it increases the advanced age resistance of the coating, its resistance to cold weather effects, and its stability performance. It has been determined by experimental studies that the use of fly ash or silica fume separately in SRP filling mortar in these recommended ratios as a substitute for cement will increase the performance of the coating.