Dr. Butt is a project scientist working for the Pavement Research Center at University of California. Davis. He also is a member of American Society of Civil Engineers (Aff.M.ASCE) and a member of TDI Committee on sustainability and environment. He also serves as a member in Center of Road2Science at KTH, Sweden, and is the reviewer of number of journals that include Journal of Cleaner Production, International Journal of LCA, IJPRT, Resources, Conservation and Recycling and others. Doing research and teaching are his passions.