The behaviour of flexibly bedded concrete paver pavements
The growth in the international usage of flexibly bedded pavers since World War II has brought about the need fully to understand how pavers bedded in sand function. The design methods are based upon the concept of making pavers and their bedding sand equivalent to conventional pavement construction materials. Experience has shown that pavers do not behave as a collection of individual units but rather interlock so that they behave in a manner close to that of flexible materials. The nature of a pavement surfaced with pavers is therefore depending on the pavers, the joints, and the way in which the two relate as well as the foundation on which the pavers rest. In this Thesis, a way in which pavers distribute stresses resulting from rolling loads has been investigated and an understanding of the interlocking process thereby developed. This Thesis explains the theoretical analysis and demonstrates how it can be used to establish the nature and value of interlock. Chapter 1 concentrates on this process by starting to introduce concrete paver pavements and goes on outlining the principles upon which the remainder of this Thesis is based. The achievement of full interlock in the surface level of a paver pavement is an essential part of any successful paver pavement. It is important to understand the principles and specifications for the materials and construction process in order to satisfy the requirements of paver pavement components. Because of this reason, Chapter 2 outlines the major contents of UK specifications for the materials and construction methods likely to be used for the construction of paver pavements. Chapter 3 is concerned with the existing structural design of concrete paver pavements carrying vehicular traffic ranging from trucks to heavy industrial vehicles and aircrafts. Design criteria for such pavements are established and a range of methods for their analysis and design are reviewed. Chapters 4 and 5 show how the variations of patch loading on the surface of pavers can be calculated. Chapter 6 presents the bedding sand stress calculation method which can be used to determine the patterns of stress within the bedding material and it shows how these patterns develop as a patch loading rolls across pavers. All possible eccentric load patches on the surface and their all vertical compressive stress distributions in bedding sand were calculated for chamfered rectangular pavers (with and without interlock), non-chamfered rectangular and nine proprietory shaped pavers. The nine proprietory shaped pavers analysed in this Thesis are commercially important on a worldwide basis. Chapters 7,8 and 9 explains how the bedding sand stress calculation method can be applied to proprietory shaped pavers. A common proprietory shaped paver has been selected as an example in Chapter 7 to show how all possible vertical compressive stress regimes of proprietory shaped pavers can be calculated for all realistically possible load patches. The remaining proprietory shaped pavers are analysed in Chapter 8. The results of the analyses presented in Chapters 5,7 and 8 are shown in Chapter 9. The results are being used in the development of paver jointing systems and it is now possible to assess more effectively the tolerances required in paver installation. Although paver pavements appear to be very simple structures they are in reality very complicated, possibly one of the most complicated of all civil engineering structures. In order to predict the future performance of paver pavements, a vast number off simplifications must therefore be made. One of the most promising approaches to this is to apply accurate modelled Finite Element Analysis obtaining the data related with systematic behaviour of paver pavements on the surface level from the results of this Thesis.