Effect of Stabilization on Geomechanical Properties of Pond Ash for Pavement Subbase Application

The shortage of traditional quality materials for road works, on one side, and the management of large-scale coal ash production from thermal plants, on the other side, are the present significant challenges for the construction industry. Therefore, using pond ash as pavement material can provide a sustainable alternative to the problems mentioned above. Nonetheless, usage of ash alone cannot demonstrate desirable engineering behavior and requires proper modification with suitable additives to improve performance. In this regard, the engineering properties of pond ash mixed with lime (8%), fiber (1%), and their two combinations have been investigated for the strength (CBR) and stiffness (MR) properties to be used as a subbase layer in flexible pavements. The individual and combined effects of additives on CBR and MR of pond ash, as well as the impact of various stress levels on MR, have been observed. Based on results obtained, it was concluded that there was a significant improvement in CBR and MR with the addition of additives. Furthermore, the experimental resilient modulus values were validated with four stress-dependent models available in the literature.