Concrete paver strength with auto weight
Concrete paver strength with auto weight
(OP)
I am specifying a 24x24x4 concrete paver with 5000psi for school site courtyard and there is a CHANCE that a car might drive over. School management is concerned pavers will chip. There will be 4" sand bed, polymeric sand finish between pavers and coutyard sides will have a poured concrete edge. How can I prove a 2" thick paver will perform well, so I do not have to go to a 4"?
Thanks for any help.
Thanks for any help.





RE: Concrete paver strength with auto weight
The 4" sand bed could be excessive and be a problem since it could become saturated due to the concrete restraint if the base is not permeable. The polymeric sand is really just a temporary excess cost item.
A heavier duty paver than can be used for car traffic is 80 mm. A normal spec for interlocking concrete pavers is 8000 psi minimum (ASTM spec) and many are in the 10,000-12,000 psi. Interlocking pavers(usually less than 8 or 9" in any direction are much smaller than what you have specified. For heavier loads like roads, airport taxiways or ship unloading facilities, 100 mm is commonly used.
Look to the Interlocking Concrete Paving Institute (icpi.org for technical information).
Dick
RE: Concrete paver strength with auto weight
RE: Concrete paver strength with auto weight
RE: Concrete paver strength with auto weight
For heavy loads, pavers should be placed on a 1" sand setting bed over a compacted base that has the desired contours for drainage or a underground drainage system in unusual situations.
Hokie66 is correct - The spaced placement method used for larger "garden variety" concrete slabs eliminates the interlock caused by the paver shape, laying pattern and the fine sand that is vibrated into the small space/gaps formed by the spacers on the paver sides. An engineered paver installation is a system and not just a collection of materials.
Clay pavers are different animal and rarely used for higher loads.
Dick
RE: Concrete paver strength with auto weight
RE: Concrete paver strength with auto weight
Most common method of placement is not on concrete but on compacted, stabilized base with 1" sand layer.
As ConcreteMasonry noted, you'll get failures with vehicle loads on these pavers. You can analyze ad nauseum, but pavers need to be governed by shear, not bending. If you have a 24" square paver, you introduce more bending than that small slab section will withstand.
RE: Concrete paver strength with auto weight
The soil was a typical international harbor soil (silt/clay) with a high water table that had a properly compacted base. The 100mm thick pavers (about 4"x8") had a "zig-zag" configuration that were laid in a herring bone pattern for greater unidirectional strength. This is very typical of many international installations that American engineers are not familiar with. Concrete pavement would not have been practical since flexible pavement was more realistic. This was similar to other applications in K-L and other SE Asia ports.
The construction was not that different than that used on many street areas that serve the large dual steering axle buses in Europe.
Dick
RE: Concrete paver strength with auto weight
The Interlocking Concrete Paver Institute has some good info on pavers.
www.icpi.org