CCP 01-31-1994 - Laserfiche WebLink

Home Browse Search

---.- I AET #93-1379 - Page 9 .' . Frost Susceptibility - The on-site soils are at least moderately frost susceptible. I Generally, these soils can heave 1/4" :t for each foot of frost penetration. Where I subgrade conditions are uniform laterally, such as where the granular borrow layer is in- place, frost movements tend to be uniform. However, where soils are mixed with I varying soil types, differential frost movements can occur. This becomes particularly pronounced where water can be locally trapped. I - Discussion I Sub grade conditions at Keithson Drive are more favorable than at the remaining road locations, particularly from a frost! drainage standpoint. This is evident in the surface pavement condition. I We suspect the sags in the roadway are associated with looser (and probably deeper) utility backfill soils which have settled in the past. We judge that most of the backfill settlement should I have occurred and future movements should be less. .. At the remaining road locations, much of the pavement distress is probably due to poor frost and I drainage properties of the soils. Even where the soils appear to have a reasonable level of stability, distress is evident. I The soil conditions portrayed by Borings #4, #5, #8, and possibly #6, also have low strength I which should be corrected. Since these areas are also associated with higher moisture contents, the frost condition is also more exaggerated. I We understand you are considering improvements ranging from overlaying the existing I bituminous to cold in-place recycling (which does not allow for subgrade preparation) to pavement reconstruction (which does allow for subgrade preparation). Our comments relative I to these approaches and the in-place conditions are as follows: I .. I