Conceptualization of toll road pavements assessment with non-destructive deflectometric testing

Toll pavements are an important part of highways, whose condition is not necessarily assessed according to strict monitoring procedures. So, they are almost overlooked when planning maintenance and rehabilitation measures. In addition, the particular nature of the concrete material typically used for toll plaza, makes it much more difficult to maintain healthy and functional structures. Examples of this include the propagation of cracks to full depth and more complex rehabilitation measures that require a complete replacement of the pavement slab, both of which are due to the brittle nature of concrete.

 

However, to ensure a resilient and sustainable road infrastructure, an accurate assessment of the condition of concrete pavements on site is crucial. Non-destructive testing enables non-invasive field inspections, and the Falling Weight Deflectometer (FWD) is the most convincing example of rapid defect detection and is a method that outperforms conventional core drilling. With this in mind, deflectometric testing was primarily used in this study to evaluate five toll plazas with in-service concrete pavements on a PPP highway for which no long-term monitoring data was available. A testing campaign was set up to evaluate the condition of each pavement slab or lane, assess the durability of the slabs, and determine the effectiveness of load transfer across joints and cracks.

 

The observed deflection variability of the slabs prompted a distribution fitting analysis to estimate characteristic values and thresholds for common deflectometric indicators, which were then verified against input data from pavement design. It is proposed to use the developed conceptual approach to establish evaluation criteria for individual slabs or damaged joints of concrete pavements, which could assist responsible decision makers in managing pavements and maximizing their resilience during their service life.