Effect of Alkaline Activator Ratio on Mechanical Strength of Fly Ash Stabilized RAP Use as Pavement Base Material

As there is a scarcity of natural virgin aggregate (VA) and increase in the construction of road projects in India and around the world, it is a common practice to use sustainable materials in pavement base and subbase applications. One instance of this is reclaimed asphalt pavement (RAP). In recent years, the usage of high percent RAP stabilized using fly ash (FA) was extensively studied by various researchers in India and across the globe. The unconfined compressive strength (UCS) is one of the important strength parameters to qualify the proposed mix as a suitable pavement material. In order to accomplish this, a series of UCS experiments with FA-stabilized RAP:VA mixtures was carried out. To enhance the reactive potential of the FA, a combination of liquid Na2SiO3:NaOH called liquid alkaline activator (LAA) was used, and the role of L on the mix strength was evaluated for different ratios of LAA. It was discovered that increasing the L ratio improved the UCS of the RAP:VA + FA mix at 28 days curing period while decreasing it at a certain LAA thereafter. As such, this research aims to determine the influence of an alkaline activator on the mix strength for pavement base/subbase applications.