Science Behind Pavement Analysis & Design
Interlocking concrete pavement systems have been proven to be a durable and effective alternative, even in vehicular applications; but, as with any proper concrete pavement design, construction and maintenance procedures are required. ASCE 58-16 was created by the ASCE/T&DI Structural Design of Interlocking Concrete Pavement Standards Committee to provide guidelines for interlocking concrete paver design and developing appropriate pavement structures for various Traffic Load Index and subgrade conditions.
This standard guideline was developed based on the 1993 AASHTO Guide for Design of Pavement Structures, which calculates the thickness of a road cross section required to withstand the traffic load index for the given lifespan based on the native soils bearing capacity. ESALs (Equivalent Single Axle Loads) express the equivalent damage created by each type of vehicle as compared to an 18,000-pound axle load. For example, passenger cars have a Vehicle Load Factor (VLF) of 0.0004 (it would take 2,500 cars to create the same damage as one ESAL) while full fire trucks range from 0.21 to 6.87.
In terms of selecting an acceptable paver for the given traffic load, both the paver thickness and aspect ratio have to be considered. The heavier the expected traffic, the thicker the paver needs to be to prevent it from flipping (rotating) out of place. Controlling the aspect ratio, which is the longest length divided by the thickness, helps to prevent the flexural loads expected from the given traffic type from exceeding the limitations of the concrete.
Paver Thickness – How to Select the Right Paver
Paver shape and thickness must be selected based on the application. Most long planks and large slabs are not suitable for vehicular applications. Concrete segmental units should be evaluated based on site-specific conditions. The project pavement engineer should confirm that the product can meet expected performance for vehicular loading conditions.
HOW THICK SHOULD A PAVER BASE BE?
