Effect of Aggregate Type on Functional Properties of Warm Mixed Asphalt Modified with Zycotherm

Nowadays, warm mix asphalt (WMA) technology is known as an efficient way to reduce costs of asphalt production, fuel consumption and environmental pollution. In contrast to its numerous advantages, stripping phenomenon comes as a disadvantage for this industry. One way of improving the resistance of asphalt concrete and adhesion between bitumen and aggregates is to use chemical and organic additives. Zycotherm, as a nano-chemical additive, plays a bilateral part: as an anti-stripping agent and as an additive for the production of WMA. To better understand the phenomenon of stripping as a result of weak adhesion, several mechanisms have been used to describe the adhesion between the components of asphalt mixture. Since adhesion between two different phases depends on mechanical and chemical reactions, molecular attraction and theory of free surface energy, the mechanisms controlling adhesion failure between the components of asphalt mixture are complicated. The main objective of this laboratory study is to evaluate the effect of aggregate type on functional properties of WMA modified with a nano-chemical additive, named Zycotherm,  as a warm mix and anti-strip agent in terms of water susceptibility tests according to the newest national and international codes such as modified Lottman test and boiling water test. To do this, indirect tensile test was also carried out. Image processing of boiling water test and analyzing the results of water susceptibility tests showed that on one side, Zycotherm had a poor performance as a warm mix additive on both limestone and silica materials; but on the other side, had a remarkable effect on improving resistance to moisture damage of silica materials.