The total reconstruction of the Pennsylvania Turnpike, begun in 1999 and completed in 2004, signifies the first time that the toll road - known as "America's First Superhighway" - has been replaced from the ground up since it opened in October 1940. Part of this massive reconstruction effort has been the stabilization of the subgrade soils underneath the roadway using portland cement.

CMS_patpk_15Subgrade soils before cement modification.

CMS_patpk_16Subgrade showing loose cement on subgrade.
CMS_patpk_05Mixing the cement and subgrade soils together with water.
CMS_patpk_12Close-up view of mixing tines.
CMS_patpk_20Subgrade material after mixing with cement and water called"fluff."

For more on the Pennsylvania Turnpike, please visit the following site: