Mesoporous silica material MCM-41: Novel additive for warm mix asphalts

This study evaluates the impact of a new generation additive MCM-41 saturated with water on the asphalt foaming. MCM-41 is a mesoporous silica material which is produced in the process of synthesis from the fly ash. Experimental design included the assessment of reference asphalt specimens as well as asphalt specimens prepared with addition of MCM-41 material from 1.5 to 4 wt%. The mesoporous silica material used in this research featured a high specific surface area and a mesopores volume of 1134 m2/g and 0.980 cm3/g, respectively. The assessment of asphalt specimens was performed in terms of dynamic viscosity as a function of time (measured after 30 and 45 min of mixing) and temperature (135 °C and 160 °C). The most significant decrease in viscosity was observed for asphalt specimens prepared with 3 wt% concentration of MCM-41 material. The results presented in this paper suggest that MCM-41 mesoporous silica material can be more effective additive to warm mix asphalts (WMA) when compared to other currently used agents (zeolites, waxes, etc.). Concurrently, synthesis of MCM-41material based on the waste materials such as fly ash is environmentally friendly and economically feasible. These results have initiated another research project which includes a comprehensive mechanical and chemical assessment of different asphalts modified with MCM-41 additive and mechanical evaluation of corresponding WMA to investigate the optimal MCM-41 content.