Field performance of asphalt mixture modified with reactive isocyanate-based modifier

The reactive isocyanate-based modifier chemically reacts with asphalt components. This chemical reaction helps overcome the issues of increased viscosity and phase separation encountered with conventional modified binders. The reactive isocyanate-based modifier can be used by itself or with other modifiers and additives to modify binders to meet the highest performance grades currently specified by state highway agencies. This project aimed to demonstrate the constructability of an asphalt mixture modified with the reactive isocyanate-based modifier in the field and compare its performance with that of a control mixture. The project involved milling an approximately 5.0 cm (2 in.) thick surface layer of two 30.5 m (100 ft) sections with similar foundation support. One section was resurfaced with a reactive isocyanate-modified mixture and the other with a conventional styrene-butadiene-styrene-modified mix. The mixtures have shown no significant difference in field performance and laboratory performance test results. This study has provided insights into the field applicability of reactive isocyanate-based modifiers in asphalt mixtures, facilitating the ongoing efforts to develop durable road surfaces.