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8.3.1 Frost Heave — Introduction Frost heave occurs in roads having fine graded, so called frost susceptible material, at a depth to which the freezing front reaches during the winter. The frost heave typically causes an uneven road surface and results in reduced travelling speed and comfort. The main problem though usually arises upon thawing […]

Calculated stiffness values, based on measured deflections under loading of a pave­ment surface, for a thin pavement structure are given in Fig. 8.6, along with the water content. One can see that the spring-thaw period started in early April as the water content at the three probes increased from 4%-7% to 12%-16% in a very […]

Accelerated load testing of pavements was done with the HVS-NORDIC at VTI in Sweden in 1998 (Wiman, 2001). Figure 8.5 shows the rut depth measurements for a weak pavement comprising a 49mm thick asphalt layer over a bitumen sta­bilised granular base of thickness 89mm over a sand subgrade 2.5 m thick (mean thicknesses). After 500 […]

In the last ten years, significant progress has been made in the measurement of in-situ water contents in pavements, using in particular TDR probes (see Chapter 3, Section 3.2.2). These measurements have shown that, often, significant amounts of water infiltrate in to pavements through the pavement surface and from the shoulders. Low traffic pavements are […]

Changes in water content, especially excess moisture, in pavement layers com­bined with traffic loads and freezing and thawing can significantly reduce pavement service life. Failures associated with moisture are detected on roads all over the Europe. There is some evidence to suggest that water has less impact on thick and well-construced pavements than it does […]

Most actual pavement design methods are based on the same principles. Linear elas­tic calculations are used to determine the stresses and strains in the pavement layers, under a reference traffic load, and then the calculated stresses and strains are com­pared with maximum allowable values, depending on the nature and characteristics of the pavement materials. Most […]

8.2.1 Different Types of Road Structures Versus Sensitivity to Water Road pavements are multilayer structures (see Fig. 1.5) generally comprising a sur­face course and one or more asphaltic or granular base layers, resting on a pavement foundation. Chapter 1 introduced the major pavement layers — the foundation, the sub-base, the pavement base and a surfacing […]

and Pavement Performance: Field Observations Robert Charlier[20], Pierre Hornych, Mate Srsen, Ake Hermansson, Gunnar Bjarnason, SigurSur Erlingsson and Primoz Pavsic Abstract This chapter presents a mechanical behaviour study, i. e. the bearing capacity as a function of the moisture degree. The field point of view is expressed and the chapter summarises a number of observations […]

Despite most regulatory constraints being based on physico-chemical analysis, the hazard toward the natural environment represented by a contaminated solution or matrix cannot simply be assessed on the basis of the single analytical approach. The latter supposes that the contaminants can all be identified and are not too numerous (which is not always the case), […]

Historically, chemical analysis of water was achieved by titration methods. It is, practically, impossible to use these on water containing a pollutant at a low con­centration due to the need to collect a very large volume of water that can be con­centrated to permit a weighable amount of chemical to be obtained at the end […]