Scanners help to prevent water damage to roads

Initial experiments conducted by Deltares, Miramap and Grontmij have shown that it is possible to measure water in and under asphalt roads and to predict where it will have an impact, both quickly and without causing hindrance. High groundwater levels and water in and under asphalt roads reduce their useful life. The early identification of moisture problems and predictions of the consequences can save road management authorities tens of millions of euros. Using soil moisture scanners and soil radar, road managers can identify problems quickly and simply, and then decide what action to take.

proefbak met scanners om water in asfalt te meten

Two scanners measuring the moisture level of the asphalt in the test vessel

New use of measurement techniques

The launch of the trial is the first step on the way to using the measurement techniques for asphalt roads. Miramap soil scanners are already used to determine moisture levels in and under dikes. ‘The subsurface and the loads on asphalt roads are different than with dikes. To use this technology for roads, you have to take another look at what the data mean, and what they tell you about the condition of the road,’ explains Arjan Venmans, a geo-engineering expert with Deltares. Deltares uses the measurement data from the test array to make improvements in a software model for predicting the impact of water on an asphalt road. The model is then used to give road managers a picture of the maintenance costs and the useful life of the road.

Test array with varying groundwater levels and rain

The new approach to using the measurement technology is being studied in a test vessel measuring roughly two x two metres. The water level in the vessel can be raised or lowered in a controlled way. Long or extreme showers can also be simulated. At a later stage, there will be field experiments on an existing road.
The specially developed soil moisture scanners will be suspended behind a truck, where they will measure the groundwater level and rainwater in the asphalt. The scanners work with passive microwave radiometry (MIRA) and they were developed by Miramap, a company that specialises in remote sensing and Earth observation. Grontmij generates a picture of the subsurface using soil radar. The test array was built by Dibec.

This project was made possible by an innovation voucher from the European knowledge and innovation programme, Climate-KIC.