International Journal of Applied Science and Engineering https://doi.org/10.6703/IJASE.202012_17(4).411 411 OPEN ACCESS Received: June 29, 2017 Revised: March 22, 2020 Accepted: October 15, 2020 Corresponding Author: Sambhav Jain sambhav29jain@gmail.com. Copyright: The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted distribution provided the original author and source are cited. Publisher: Chaoyang University of Technology ISSN: 1727-2394 (Print) ISSN: 1727-7841 (Online) Laboratory investigations and performance evaluation of stone matrix asphalt as a wearing course using three different fibers Sambhav Jain 1* , Harpreet Singh 2 , Tanuj Chopra 3 1 Department of civil engineering, Thapar University, Patiala, India 2 Standard & Research Zone, MoRT&H - IIT Roorkee, Delhi, India 3 Department of civil engineering, Thapar University, Patiala, India ABSTRACT Bituminous mixtures are used as wearing and base course layers in a pavement structure and the performance of these mixes can be defined by its resistance against deformation, fatigue cracking, damage due to moisture and overall stiffness of the mixture. Rutting is one of the most important factors that lead to permanent failure of flexible pavements. The stone matrix asphalt (SMA) mixture is known to be highly rut resistant than other conventional wearing courses such as bituminous concrete. This paper describes the experimental examination conducted on stone matrix asphalt (SMA) mixes prepared using VG 30 grade of bitumen and different types of fibers such as cellulose fiber, coconut fiber, glass fiber and jute fiber as their additives. Results were then collated with SMA mixes prepared with different types of fibers. Investigation work comprises SMA mix design, static indirect tensile strength (ITS) and drain down test. From the test results, it was perceived that SMA with cellulose fiber has higher Marshall Stability and slightly lower drain down percentage as compared to all other fibers used. But indirect tensile strength for SMA mix prepared with jute fiber was higher than all other mixes. Keywords: Cellulose fiber; Coconut fiber; Glass fiber; Jute fiber; ITS; Drain down. 1. INTRODUCTION Stone matrix asphalt (SMA) is a gap graded mixture containing high amount of coarse aggregate and less percentages of fine aggregate with high fraction of mineral filler and binder content (Fig.1). Normal stone matrix asphalt (SMA) mix comprises of about 70- 80% of coarse aggregate whereas conventional mixes contain about 40-60% of coarse aggregate. In SMA mix, the normal binder content is more than 6%. Strength of these mixtures comes from the stone on stone contact imparting from the coarse aggregate skeleton and durability comes from the high binder content. The strength and performance for stone matrix asphalt (SMA) is generally high as compared to other asphalt mixes (bituminous concrete mixes) (Singh et al., 2017; Singh et al., 2019; Singh et al., 2019). Due to gap gradation, binder may drain out from the mix at the time of placing, production and storage. This can be overcome by the addition of a stabilizer. This paper includes the addition of four different stabilizer additive i.e. cellulose fiber, coconut fiber, glass fiber and jute fiber. The performance of the mix with different fibers is evaluated and then compared. The performance studies such as indirect tensile strength test (ITS) (ASTM, 2017) and drain down test (ASHTO, 2017) were conducted and the results were compared for four different stabilizing additives. Stone matrix asphalt was first developed in Germany in 1960 and since then many case studies have been conducted over stone matrix asphalt (Bindu and Beena, 2010;