Resilient Modulus of Compacted Fly Ash for Pavement Applications

Abstract

Fly ash is one of the waste materials generated in large quantities across India. As per Central Electricity Authority (CEA) report, nearly 196 million tons of fly ash is generated in the year 2017–2018 in India from nearly 167 thermal power stations. Of the generated quantity, only about 60% is utilized for various applications, and a minor portion of it (about 3.4%) is being utilized in roads and flyovers. This study focuses on utilization of fly ash in large-volume embankment construction. When pavements are built over compacted fly ash, resilient modulus (MR) of compacted ash is one of the key factors considered in the design of pavements. In the present study, fly ash collected from Neyveli Lignite Corporation (NLC), Neyveli, India is used to evaluate the resilient modulus of compacted fly ashes. Cyclic triaxial setup is used to test the resilient modulus of the fly ash. The resilient modulus tests are conducted at three different water contents, optimum water content, and ±2% of optimum water content. Samples are cured for two different curing periods, equal to 6 h and 24 h. The resilient modulus tests showed that the fly ash exhibited good pozzolanic property with the passage of time. The MR value at OMC for fly ash at 6 h of curing is in the range of 70–80 MPa, whereas for 24 h of curing the MR value is in the range of 80–115 MPa. The proposed MR can be helpful to designers to design the thicknesses of pavement layers constructed over embankments made up of compacted fly ash.