Role of Lime-Fibre on Mechanical Strength and Resilient Characteristics of Pond Ash

Shortage of traditional pavement materials on the one hand and management of vast output of coal ash from thermal power stations on the other hand are the major challenges facing the construction industry. In this regard, the present work is focused on the investigation of laboratory studies—aimed to evaluate the use of coal pond ash as a pavement subbase material. A series of unconfined compression, bearing ratio and repeated load triaxial (RLT) tests were performed on pond ash through the individual and combined effect of lime and fibre contents to investigate the pavement-geo mechanical parameters such as unconfined compressive strength (UCS), California bearing ratio (CBR), resilient modulus (MR), and permanent deformation (ϵp). The effect of additives and the impact of various stress levels (both confining and deviatoric) on pond ash were investigated. The test results indicate that there was a significant improvement in the above properties of pond ash with an addition of lime and fibre. The optimum performance of pond ash was observed at lime content of 8% and fibre content of 1% individually. The combined effect of both additives further enhanced the efficiency of pond ash significantly up to lime 8% + fibre 1.0%; thereafter, the improvement was minimal for increased additive contents. The measured MR and ϵp values were compared and validated with the existing mechanistic-empirical prediction models and observed satisfactory results.