Innovative solutions to buried portland cement concrete roadways : second interim.

PDFTech Report99-11Portland cement concreteBituminous pavementsConcrete pavementsRigid pavementsSettlement (Structures)Longitudinal crackingHot mix paving mixturesInnovationConstructionMaineMaine. Dept. of TransportationMarquis, BrianMaine. Dept. of Transportation. Transportation Research DivisionUS Transportation CollectionMaine has hundreds of miles of highway that were constructed ofPortland Cement Concrete (PCC) roughly 6 to 6.1 m (18 to 20 ft) wide fortyor more years ago. Since that time these same highways have been pavedand widened to 6.7 or 7 m (22 or 24 ft) with hot bituminous pavements toaccommodate increased traffic volumes. Bituminous materials were used inplace of concrete due to the ease of placement and price of material.PCC is a rigid pavement capable of supporting weight with littledeflection. Hot bituminous pavement is flexible and will bend to distributeweight across the roadway. When the highway is expanded beyond theconcrete slab there is a sharp decrease of support for this bituminouspavement resulting in settlement over prolonged use. This settlement mayalso be compounded by poor drainage capabilities of the underlying soilscausing the unsupported pavement to drop lower than the existing height ofthe concrete supported pavement. This creates a longitudinal crack aligningwith the concrete slab edge about 0.3 to 1 m (1 to 3 ft) from the right edge ofpavement. Pavement to the right of this crack deteriorates to the point wheremaintenance crews attempt to smooth it out with cold patch year after year.Paving over the entire roadway is an option but, due to reflective cracking,the edge of pavement begins to deteriorate within 2 or 3 years