The concept of water balance is frequently used to describe the main hydrological processes occurring in natural catchments. It can also be applied to urban catchments and in this paper the water balance principle is applied to small-scale samples of various paving materials. In particular, the relative importance of runoff, evaporation and infiltration is studied. This paper discusses these processes and describes some experimental measurements of water balance on various paving materials and the moisture content distribution within the materials.

This paper concerns an investigation of evaporation, infiltration and detention storage on paved surfaces and the effect of surface texture and microtopography on these processes. A numerical model has been developed which represents the evaporation and infiltration processes on a nominally impervious surface as well as the depression storage due to the surface microtopography. The model was applied to semi-randomly generated surfaces and the results show the relationship between surface microtopography and initial storage losses.

The use of ultrasound is recognised as a means to obtain information about concrete with nondestructive testing. Various aspects of the material can be characterised. However, the scientific literature in this area is quite sparse. The present paper therefore addresses the issue of moisture content, and related compressive strength, in a systematic experimental manner. The moisture content profiles of 24 concrete cubes under constant simulated precipitation over 24 h were investigated using ultrasonic methods. Different values of water/cement ratio, duration of pre-curing vibration and curing regime were used. The propagation time of ultrasonic compression wave pulses gave a good correlation with gravimetric moisture content and it was found that the type of curing and the amount of vibration had the greatest impact on the propagation time of the ultrasonic wave. The moisture diffusion coefficient was estimated using a simple finite difference model and good agreement was achieved with experimental measurements.