Because pavement design is empirical and as a result there are several methodolgies, this may never happen. The local agency I design for still utilizes nomographs to design rigid and fleixible pavements. Other agencies require a particular software and they'll provide it for you when you work on their jobs. There are several free software out there, such as SpectraPave from Tensar. Any pavement design software that Autodesk may incorporate into CIvil 3D would, like Hydraflow Express, have to be an exterior application, independant of Civil 3D. Because free applications such as SpectraPave exist and because pavement design is emperical and agency specified, I can't see how Autodesk will do this, unfortunately. Maybe they can provide a free license for AASHTOWare Pavement Design with each CIvil 3D subscription?
Because so much of pavement design relies on sub-grade conditions, a broader request would be to ask for geotechnical software that goes beyond roadway structure to include slope stability, retaining wall analysis, seepage, etc. But then we are back to same issue as before; there are free software from FHWA located here... http://www.fhwa.dot.gov/engineering/geotech/software.cfm or you can pony up some serious moolah for Geoslope.