Performance of the University of Newcastle high capacity tensiometers

New high capacity tensiometers have been developed at the University of Newcastle, Australia, for the direct measurement of soil matric suction. Consistent with other high capacity tensiometers found in literature, the design was based on a high air entry ceramic, water reservoir and pressure transducer. Different geometries (size of water reservoir), materials (stainless steel and perspex) and pressure transducers were considered when designing the tensiometers in order to investigate the significance of each parameter. The performance of the different configurations for the new high capacity tensiometers were assessed and discussed in terms of minimum pressure range and response time. The results show that all tensiometers read comparable values of suction, regardless of their inherent specificities. In particular, for all design types, the maximum suction was measured to be equal or greater than the nominal air entry value of the ceramic. This suggests that the measuring range does not depend on the size of the water reservoir.