Pavement Design for Large Element Paving Slabs

Segmental paving slabs are seeing increased use in the U.S. and Canada in municipal,
commercial and residential vehicular applications. Currently, there are no structural design
guidelines in North America for such applications. In addition, there are no structural
guidelines for precast concrete ‘planks’ (long, thin units), thin paving units (sometimes called
tile pavers), or large‐format units (sometimes called mega‐slabs). The lack of rational design
data likely places manufacturers, contractors and purchasers at risk, increasing the probability
of failures.

This paper outlines the results of a literature survey and finite element modelling that was
completed for a series of combinations of experimental variables that induced tensile stresses
and slab deflections resulting from the combination of material properties, slab dimension, and
support structure for typical vehicle/loading levels. The stresses were compared to various
flexural strengths to determine a stress ratio matrix. The matrix provides design guidance for
the use of large element paving slabs for both flexible (slabs over a granular base) and
composite (slabs over a lean concrete base) for pedestrian, low, moderate and higher traffic
levels. Details on the modelling method and parameters including a parametric study of load
positioning are provided. Design charts are provided for various configurations of square,
rectangular and plank paving elements.

The results of this study provide a logical and defendable approach to the structural design of
pedestrian and roadway designs surfaced with large element paving slabs and tiles. While the
approach taken is considered to be conservative, the validity of the designs would benefit
through validation based on field observation or accelerated load testing.