The iteration stops once a predetermined level of tolerance has been reached between subsequent calculated estimates. The process begins with a hypothesis of a given layer’s modulus, which is repeatedly compared with the FWD’s output using an iterative mathematical model. (71)īackcalculation: An iterative process by which pavement layer moduli, or other stiffness properties, are estimated from FWD deflection data. (72)Īxle load: Load exerted by a vehicle on the pavement surface via an axle.īase: The layer or layers of specified or select material of designated thickness placed on a subbase or subgrade to support a surface course layer directly beneath a PCC slab. Also referred to as hot-mix asphalt (HMA).
![backcalculation of pavement layer properties backcalculation of pavement layer properties](https://www.researchgate.net/profile/Hyung-Lee-2/publication/322509258/figure/tbl8/AS:668599727448068@1536418005180/1-Assumed-Pavement-Properties-for-Backcalculation.png)
(71)Īsphalt concrete (AC): A controlled mixture of asphalt cement and graded aggregate compacted to a dense mass. The analysis period should not be confused with the pavement’s design life (performance period).
![backcalculation of pavement layer properties backcalculation of pavement layer properties](https://www.fhwa.dot.gov/publications/research/infrastructure/pavements/16010/images/fig02.png)
(71)Īnalysis period: The period of time used in making economic comparisons between rehabilitation alternatives. (70)Īlligator cracking: Interconnected or interlaced cracks forming a pattern that resembles an alligators hide.
![backcalculation of pavement layer properties backcalculation of pavement layer properties](https://www.mdpi.com/materials/materials-14-00873/article_deploy/html/images/materials-14-00873-g003.png)
Using Falling Weight Deflectometer Data With Mechanistic-Empirical Design and Analysis, Volume III: Guidelines for Deflection Testing, Analysis, and InterpretationĪggregate: A collective term for the mineral materials such as sand, gravel, and crushed stone that are used with a binding medium (such as water, bitumen, portland cement, lime, etc.) to form compound materials (i.e., asphalt concrete, portland cement concrete, etc.).