In Situ Measurement of the Capillary Pressure in Concrete Road Construction

Concrete pavements are vulnerable to cracking already in the plastic material stage, i.e., before the concrete has reached a significant strength. Due to the evaporation of water at fresh concrete surfaces, a capillary pressure is built up in the pore system of the material. This underpressure leads to the so-called capillary or plastic shrinkage and possibly to cracking. Since the capillary pressure provides direct information on the response of the concrete to the water loss by evaporation, it may be used to estimate the cracking risk in situ and to control curing procedures. At the examples of an on-site measurement, the applicability of capillary pressure sensors is demonstrated and discussed.