Evaluation of the uses of treated sawdust as a partial replacement for aggregate in hot mix asphalt

Abstract

Undoubtedly, the damage to the upper layer of the road pavement caused by a tremendous load of vehicles and climate factors is an alarming and challenging fact to both government and researchers in the respective field. Thus, and with the aim to come up with a remedy, the potential of sawdust, as a renewable material for replacing aggregate in hot-mix asphalt, was examined. Therefore, a full factorial design of experiment (DOE) was conducted to evaluate the effects of sawdust content (5%, 10%, and 15% of total aggregate volume) on Marshall stability flow values and density. The range of binder from (5.77% to 6.45% means from low level to high level) and the temperature of mixing (140°C to 180°C) and the time of mixing (2 minutes to 4 minutes) as well. Also, to improve its durability, the sawdust was treated with an established emulsion coating. Accordingly, it has been demonstrated in this study that sawdust can be utilized as a partial replacement for (3/8) aggregate. Indeed, the use of this renewable material resulted in an increase in Marshall stability, a decrease in density, and flow values within the accepted range, leading to a positive environmental impact. Additionally, sawdust is considered a waste material, making it cost-effective. Ultimately, the acceptance criterion allows for the replacement of up to 7% of the aggregate for both low and high-level values; however, if more than 7% is replaced, only the highest-level value is considered acceptable. Thus, an economically and technically efficient solution may have been provided by this study.