Granular base equivalency or granular base equivalence (GBE) is a measure of total pavement thickness. Since pavement is composed of multiple layers with different physical properties, its total thickness is measured by GBE. GBE translates the thickness of different road layers to a number using a set of coefficients. So, to calculate the GBE, the depth of each layer should be multiplied by the granular equivalency factor for the material in that layer. In the next step the sum of the converted layer thicknesses is calculated. This sum is called granular base equivalency, which is a popular and important measure in pavement design and

pavement performance modeling Pavement performance modeling or pavement deterioration modeling is the study of pavement deterioration throughout its life-cycle. The health of pavement is assessed using different performance indicators. Some of the most well-known performanc ...

Example

Here is an example of GBE calculation adopted from Piryonesi (2019). This example belongs to a road in the

LTPP Long-Term Pavement Performance Program, known as LTPP, is a research project supported by Federal Highway Administration (FHWA) to collect and analyze pavement data in the United States and Canada. Currently, the LTPP acquires the largest road p ...

database. This road is made of the following layers: subbase, base, and three layers of hot mixed asphalt concrete. Their thicknesses are given in millimeters in the following table. The total GBE for this road 805.7 millimeters.

References

{{Road types Pavements Pavement engineering