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A platform for research: civil engineering, architecture and urbanism
PENNDOT's Efforts to Improve Pavement Subgrade during Highway Reconstruction
Like many highway agencies, the Pennsylvania Department of Transportation (PENNDOT) faces the challenge of aging roadways where the pavement has effectively reached the end of its serviceable life. In many cases, complete pavement reconstruction is warranted. Among other advantages, pavement reconstruction offers the opportunity to replace or improve the pavement foundation. Recognizing that the underlying subgrade on many Pennsylvania roadways consists of wet, fine grained soil that can be problematic, PENNDOT sought to develop procedures and specifications to improve the pavement subgrade during reconstruction. Working jointly with industry, PENNDOT developed new specifications for subgrade improvement that allow the contractor to select the improvement method from two options — remove and replace the undesirable soil or chemically stabilize the existing soil with lime, lime and fly ash or lime kiln dust (LKD). Lime, lime-fly ash and LKD stabilized soil are engineered products that must be properly evaluated, proportioned and constructed in order to obtain the good long-term performance that PENNDOT seeks. This evaluation is to be done by the contractor during construction — contractor-designed soil stabilization. This paper: (1) Summarizes the issues with wet, weak pavement subgrade soil. (2) Describes the options for improving the subgrade soil (per the new PENNDOT specification). (3) Summarizes PENNDOT's new specification provisions for soil stabilization. (4) Describes PENNDOT's engineering criteria for contractor-designed soil stabilization using lime, lime-fly ash and lime kiln dust. (5) Reviews bid costs of the options from bid tabs on the pilot projects.
PENNDOT's Efforts to Improve Pavement Subgrade during Highway Reconstruction
Like many highway agencies, the Pennsylvania Department of Transportation (PENNDOT) faces the challenge of aging roadways where the pavement has effectively reached the end of its serviceable life. In many cases, complete pavement reconstruction is warranted. Among other advantages, pavement reconstruction offers the opportunity to replace or improve the pavement foundation. Recognizing that the underlying subgrade on many Pennsylvania roadways consists of wet, fine grained soil that can be problematic, PENNDOT sought to develop procedures and specifications to improve the pavement subgrade during reconstruction. Working jointly with industry, PENNDOT developed new specifications for subgrade improvement that allow the contractor to select the improvement method from two options — remove and replace the undesirable soil or chemically stabilize the existing soil with lime, lime and fly ash or lime kiln dust (LKD). Lime, lime-fly ash and LKD stabilized soil are engineered products that must be properly evaluated, proportioned and constructed in order to obtain the good long-term performance that PENNDOT seeks. This evaluation is to be done by the contractor during construction — contractor-designed soil stabilization. This paper: (1) Summarizes the issues with wet, weak pavement subgrade soil. (2) Describes the options for improving the subgrade soil (per the new PENNDOT specification). (3) Summarizes PENNDOT's new specification provisions for soil stabilization. (4) Describes PENNDOT's engineering criteria for contractor-designed soil stabilization using lime, lime-fly ash and lime kiln dust. (5) Reviews bid costs of the options from bid tabs on the pilot projects.
PENNDOT's Efforts to Improve Pavement Subgrade during Highway Reconstruction
Cole, Lawrence W. (author) / Cepko, Christopher (author)
Airfield and Highway Pavements Specialty Conference 2006 ; 2006 ; Atlanta, Georgia, United States
Airfield and Highway Pavement ; 284-294
2006-04-28
Conference paper
Electronic Resource
English
PENNDOT's Efforts to Improve Pavement Subgrade during Highway Reconstruction
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