Reconstruction of a high volume bus lane using cellular concrete

ABSTRACT: Roadways constructed over frost susceptible soils often experience excessive heave as the subgrade soils freeze, followed by softening during spring thaw. This paper examines a case study for reconstruction of a high traffic bus lane over frost susceptible soils in the City of Calgary using lightweight cellular concrete (LCC). Subgrade conditions at the site were comprised of a wet, frost susceptible, silty clay. As a result, the roadway was experiencing severe frost heave during winter conditions. Also, the high volume of heavy bus traffic was creating rutting of the roadway surface, necessitating yearly repairs. Reconstruction was completed in the summer of 2000 using a layer of LCC to insulate and strengthen the roadway subbase. Benkleman Beam testing performed shortly after construction produced minimal deflections. Since reconstruction, no maintenance of the roadway has been required.