History - 1994

Data Acquisition

HVS testing only becomes valuable if the responses of the pavement to traffic loading and environmental changes are accurately recorded, analysed and interpreted. The HVS test data are obtained through careful measurement of pavement response, which is evaluated and interpreted. The system allows for the recording of 256 data points measured with the RSD, or on each of the levels of the MDD, or, in the case of the CAM, 256 points in each of the vertical or horizontal crack movement directions.

The same process is followed with the HVS Laser Profiler and the SOPT or PAST gauges. This facilitates intensive analysis of the data. The raw data are processed using the HVS standard data processing software and then stored in the HVS database. The specially developed data acquisition hardware and software allows high accuracy (10 microns) combined with the ability to measure permanent deformation of up to 150 mm. deformation of up to 150 mm.

The data recorded over the past 20 years of HVS testing are contained in a 4 000 Mbyte database. In addition to information recorded related to the HVS tests conducted, such as applied load and number of repetitions, etc., the data include plastic deformation and elastic deflection basins measured on the surface, as well as in-depth during testing. The deflection basins each contain 256 measuring points and are measured at different levels in the pavement structure. Information such as crack movements, pavement structure, temperatures during testing, traffic category and location of the tests is also recorded. The table below indicates the types of pavement tested in South Africa (as percentages), categorized into base and subbase types.