Utilization of Fiber Modified Stone Matrix Asphalt (SMA) Mixes in Egypt

Abstract

Stone matrix asphalt is considered to be a gap graded hot mix asphalt which was first used and placed in Germany as it showed to be a hard, durable, and rut resistant mixture which makes it perfect to use in the areas with heavy loaded traffic in order to avoid rutting. SMA mixtures mainly consists of high proportion of coarse aggregate, very low percentage of fine aggregate, significantly high proportion of mineral fillers, and high percentage of bitumen. Due to the existence of high bitumen content in SMA mixture, stabilizing additives must be added to the mix to avoid draindown of bitumen during transporting or placing the mix and to maintain the consistency of the mix. According to worldwide recommendations, cellulose and mineral fibers are the best additives to be added to SMA mixtures with dosage around 0.30 % of total weight of the mix, but due to lack of those materials in some countries, many researches have been done in order to replace those materials with local ones which can be cheap and available.