Activity: Talk or presentation › Oral presentation
In the Netherlands the drinking water network comprises over 120,000 km of infrastructure. Nearly 50% of the pipes is made of polyvinyl chloride (PVC) and just about 30% is made of cementitious materials. The condition of the majority of these assets remains unknown. Maintenance budget destination and decision-making on replacement of assets is challenging without information on the condition of the network. Inspecting the water network improves the management of assets and leads to an efficient replacement plan of the faulty pipes. Therefore, an inspection methodology is proposed which enables the detection and the measurement of degradation in the water pipes.
The long term interaction of the pipes with the conveyed drinking water and surrounding soil induces a layer of deterioration on both surfaces of cementitious pipes. The ultrasonic signature of these layers can be determined with ultrasonic pulseecho (PE) technique. Leaching of calcium is the main degradation mechanism of cement-based pipes. For this reason, mortar specimens were partially submerged in Ammonium Nitrate solution at different exposure times. Four degradation depths were induced: 2.45, 3.2, 3.8 and 5.6 [mm]. Results show that by calculating the overall speed of sound in the material it is possible to detect degradation as small as 2.45 [mm]. This method has enabled higher sensitivity to thin degraded layers which was still a limitation from previous research. Furthermore, the reflected amplitude from the water-degraded mortar interface can be used for detecting early stage degradation as well. Moreover, the generation of images from full scan of the specimens facilitates the detection and localization of different degradation levels.