Iron slag powder is a by product that can be obtained during steel manufacturing. Using iron
slag powder in road paving can have many environmental advantages such as keeping clean
environment and saving natural construction materials. This paper discusses the effect of using iron
slag powder on Marshall Stiffness and indirect tensile strength of hot mix asphalt. Three hot mix
asphalt with various iron slag contents, namely; 0%, 10% and 20% by weight of total mixture were
studied. Laboratory testing showed an enhancement in different Marshall Properties and indirect
tensile strength of hot mix asphalt modified with iron slag. As the iron slag content increases, the
Marshall Stability and indirect tensile strength of the studied mixtures increases as well. This is an
indication of mixtures performance improvement in addition to the fact that iron slag powder can be
used in asphalt paving for environmental advantages.