U-MicroPaver: Novel Laboratory Paving System for Slurry Surfacing Mixtures

The need for sustainable and cost-effective pavement maintenance has increased interest in slurry surfacing (SS), a family of surface treatments designed to restore the functional properties and extend pavement service life. Despite the existence of international standards for mix design and application, a major limitation in research is the lack of laboratory equipment capable of replicating SS laying. This gap has limited prequalification studies on expected surface performance, making field trials the only viable but costly and time-consuming option. This study introduces the U-MicroPaver, an innovative and patented laboratory prototype designed to simulate SS laying under controlled conditions. To evaluate its reliability, two microsurfacing mixtures with distinct gradations (BA06 and BA08) were employed, and their surface performances were systematically analyzed through a statistical evaluation on texture profiles collected via laser profilometer. Additionally, skid resistance (pendulum test), volumetric texture depth (sand patch test), and drainability were examined. Statistical analysis of laser data confirmed that the U-MicroPaver achieves a consistent and uniform application, with surface texture measurements following a normal distribution and homoscedasticity (p-values>0.05). Specifically, Mixtures BA06 and BA08 reported mean profile depth values of 1.798 and 2.224, with standard error-based 95% confidence interval of ±0.115 and ±0.096, respectively. The results confirmed that the mixture’s surface properties align with the existing literature. Additionally, the study provides an initial contribution to the study of the hydraulic conductivity of microsurfacing mixtures. Particularly, BA08 showed outflow times approximately 2.5 times shorter than BA06 and nearly 12 times faster than a common dense-graded friction course. By enabling detailed prequalification studies, the U-MicroPaver supports the mix design process and bridges critical gaps in the evaluation of SS functional characteristics. This innovation represents a significant step forward in promoting a broader adoption of sustainable pavement maintenance techniques through efficient and reliable surface treatment assessments.