Municipal Pavement Design
Municipal Pavement Design
(OP)
I recently ran across a City street standard requiring 5000 psi concrete strength in 28 days. My recollection of the AASHTO Road Studies indicated that the purpose of pavement is to shed water and transfer wheel loads to the subgrade. I seems to recall that there isn't much difference in load transfer between 3000 psi pavement and 5000 psi pavement for a given depth of pavement. Wouldn't this City be better off requiring additional depth of concrete rather than the high strength? Or better yet, putting the additional cost of cement in the improvement of the sub-grade?





RE: Municipal Pavement Design
The function of a concrete pavement is not simply to tranfer load to the subgrade, but to mitigate that load as well.
As with many other applications of engineering, it is better to specifically tailor the pavement to the needs of the roadway, not meet some nebulous, generalized criteria.
RE: Municipal Pavement Design
RE: Municipal Pavement Design
RE: Municipal Pavement Design
RE: Municipal Pavement Design
Even though you are in the south, durability is still an issue. (I practice in the south, as well). Not necessarily freeze-thaw durability, but other durability such as paste integrity, abrasion resistance, shrinkage, etc.
For all exterior pavements and interior pavements subject to forklift traffic, a minimum 4000 psi concrete should be used. The aggregate should be as large as practicable and proper jointing should be done to reduce shrinkage crack potential. Thickness tolerances should also be controlled by careful attention to subgrade flatness and finish of the concrete.
RE: Municipal Pavement Design
RE: Municipal Pavement Design
Don't forget that what ever strenght or thickness you use, municipal pavement will always endure threnches to repair the underground infrastructures. This is true for all type of municipal pavement, and considering the life span of concrete this even more true. The main problem with concrete pavement is that the backfilling and repairing procedure is very expensive and many municipalities are cutting costs, so the infrastructure maintenance suffers. So, always consider that when designing; Extra cost at the beginning will not pay off if not maintain and repair properly during all of the life cycle.
Neville Parker, CCNY-CUNY, is very knowledgeable on the matter.
Please be tolerant with my english writing.
I work for the Center for expertise and Research on Infrastructures in urban areas.
www.ceriu.qc.ca