This project involved a geotechnical investigation to evaluate the cause of the roadway paver pavement failure on Maryland Avenue and recommend new pavement sections for new bituminous concrete and paver pavement.  The investigation included: a review of the paver pavement design plans and specifications, construction records, and other documents related to pavement performance; review of lab tests on subgrade and base material; and an evaluation of the existing paver design with respect to design criteria, traffic and site conditions. 

An investigation was performed to document the as-built conditions of the failed pavement as well as provide the subsurface data needed for the design of the new pavement.  Both soil borings and test pits were performed to document as-built conditions and evaluate the soils.  Laboratory testing was performed to determine the classification, degree of compaction and California Bearing Ratio (CBR) of the base materials and subgrade.  It was determined that original design failed to provide adequate drainage and frost protection of the base materials.

New pavement sections using concrete block paver surfacing were designed for the roadways and pedestrian plaza areas.  There were severe time constraints for the reconstruction because the project was scheduled to open in a few months.  To eliminate the need for constructing an extensive subsurface drainage system, the new pavement section for the roadways utilized a bituminous base and sand-asphalt leveling course below the paver surface.

Lab Testing:

• Soil Classification
• Density and Compaction
• California Bearing Ratio

• Comprehensive documentation of the as-built conditions for the failed pavement for potential future legal action by the City of Rockville.
• Time constraints for reconstruction of new pavement.