Biocementation of road pavements: An experimental investigation through physical modeling and accelerated testing

Biocementation, owing to its non-intrusive nature, holds great promise as a non-disruptive solution for improving road pavements, particularly for rehabilitating those experiencing deterioration. The present study provides a direct proof of concept for this application. Full-depth physical models of a three-layer pavement structure, uncemented and biocemented, were constructed and subjected to accelerated testing under increasing wheel loads, with laser scanning and particle image velocimetry (PIV) combined to monitor surface and subsurface deformation. The results showed that both models exhibited a depression in the wheel path and an upheave on the side. The enhanced structural integrity of the biocemented model allowed it to experience significantly reduced deformation while sustaining higher loads. PIV analysis of subsurface displacement and strain fields revealed distinct deformation mechanisms. The uncemented model experienced localized failure within the poorly compacted base with a predominantly contractive response, while the biocemented model involved an active, vertically displacing zone beneath the wheel that underwent volumetric dilation, which was laterally confined by a passive zone on the side. These findings clearly demonstrate the effectiveness of biocementation in improving the structural performance of pavements. However, low treatment efficiency under unsaturated conditions presents a critical challenge for field implementation and warrants further investigations.