Interlocking Concrete Pavements also known as block pavements are one of the integral parts of the pavement system in Europe. The use of ICP slowly extended to other countries including North America. As the usage increased the need for more scientific research was developed which resulted in the study of ICP design and analysis methods, construction practices and materials specifications. This thesis presents a research project involving the design, construction, instrumentation, performance modeling and other field tests of eight ICP crosswalks with four different design assemblies. The research projects were constructed at the Centre for Pavement and Transportation Technology (CPATT) Test Track and at the University of Waterloo Ring Road. Each of the test sections is instrumented with structural and environmental sensors of sensors to monitor the pavement performance under heavy truck traffic, typical municipal loadings and to quantify environmental effects. A database is generated and the measured stress, strain, temperature and moisture measurements are analysed to evaluate the expected long-term performance of the structural components of ICP crosswalk designs.

No description available.

No description available.

No description available.

No description available.

A modern road pavement is a highly complex structure. Paving materials can exhibit non-linear and time dependent material properties whilst subjected to complicated three-dimensional loading conditions that are functions of the specific construction of each pavement. Nevertheless, empirical or linear elastic techniques, which cannot fully describe such factors, are often used in road engineering to assess pavement deterioration. An alternative approach is the use of finite element techniques, incorporating more complex constitutive models, to describe the response of asphalts and other paving materials. This thesis is concerned with the experimental determination of the model parameters necessary for the characterisation of two UK asphalt mixtures, for use in a dynamic plasticity based constitutive model to simulate paving material response. The constitutive model is under development at Delft University of Technology in the Netherlands, where it will be implemented in a three-dimensional finite element code. The thesis describes the constitutive framework for the material response model. It also details the experimental work and numerical verification undertaken in the study to enable the determination of the basic model parameters required to describe a 10 mm dense bitumen macadam and 30/10 hot rolled asphalt mixture, for use in the constitutive model. The characterisation of the mixtures has been undertaken through a series of quasi-static uniaxial compression and tension tests, which due to the significant influence of strain rate and temperature on the response of the asphaltic materials, were undertaken over a range of displacement rates and temperatures. Through specification of key model parameters as functions of material strength, temperature and strain rate, and the development of relationships describing the hardening and softening characteristic of the mixtures, the constitutive model has been successfully utilised to simulate the temperature and rate dependent stress-strain response of the asphalt mixtures to compressive loads.

Current available methods for the design of unpaved roads, with and without geosynthetics, were used for sixteen full-scale test sections which were constructed at the Bothkennar Soft Clay Site, Airth, Scotland. The full-scale trials consisted of twelve pavements including geosynthetics and four control pavements incorporating two types of aggregate and two design life expectancies. The test pavements were instrumented to monitor the transient stress and strain distribution, permanent strain distribution, geosynthetic temperature and ground water level during the trafficking operation. Traffic loading was provided in two stages by a standard road-going vehicle. The vehicle used for Phase One applied an 80kN axle load and in Phase Two a 126kN axle load. Failure of the pavements was defined as a rut depth of 150mm. The passage of 2115 axles resulted in failure of three sections and significant deformations in many others. Back-calculation to compare predicted and measured performance was performed and hence the existing design methods were critically assessed. Where possible the measurements obtained from field trials were used to examine the assumptions made within the design methods. The existing design methods were found to be essentially static in approach and did not model transient stresses and strains or permanent strain development adequately. Pointers towards a new approach ensuring strain compatibility between the elements of the system are suggested. This should enhance the ability of the engineer to assess the value of differing products used in this application.

Alternative materials represent an important potential source of aggregates for road construction. At present, their use remains limited owing to the abundance and low cost of high quality natural aggregates, low costs of landfill disposal and generally restrictive specifications for pavement materials. Nevertheless, their influence in relation to the primary aggregates is likely to increase in the future with the enforcement of more strict environmental regulations at national and European levels. The objective of this research project was to investigate a wide range of alternative materials and provide a practical framework for their assessment enabling pavement engineers to deal with most applications in road construction. Initially secondary materials were assessed according to the present UK specifications and were found to fail the requirements in most cases. However, the current approach does not assess fundamental properties such as stiffness, resistance to permanent deformation, tensile strength, resistance to fatigue and the development of these with time, leading to an inadequate assessment of these materials. To advance towards the development of performance-based specifications repeated load triaxial and indirect tensile tests were used. For their performance the Nottingham 150x300 mm triaxial apparatus was used and an indirect tensile apparatus developed which evolved from the Nottingham Asphalt Tester used for bituminous materials. In triaxial testing, models used to study the resilient behaviour of granular materials were found to give good results for unbound but not for lightly-treated secondary materials. For these, a new resilient model was developed. Testing and specimen preparation techniques together with performance classification systems were developed for both tests and recommendations for an overall methodology for the evaluation of secondary materials are presented. An application of this methodology was made to the study of thirteen mixtures to be considered for full-scale trials. The application of secondary materials in pavements was evaluated using analytical methods of pavement design which demonstrated the potential of these at levels in the pavement as high as the roadbase and the overall thickness reduction that may result.

In order to achieve the goals of 'Sustainable Development', alternative (secondary) materials are being increasingly used as bulk-fill aggregate within pavement construction as substitutes for traditional aggregates. This finds an end-use for stockpiles of industrial by-products (and hence the allowing the land on which they stand to be reclaimed for other uses) and protects finite, natural resources which they replace from over-extraction. Previously, there has been very little research concerned with the leaching of contaminants from alternative materials in pavement construction and the subsequent risks to water bodies from pavement drainage. It is this topic which is addressed here. Two flow regimes within a pavement have been studied in order to predict contaminant movement: (1) vertical flow through the aggregate and pavement and then vertically through the natural subgrade to ground water below and (2) horizontal flow through the aggregate to be discharged through pavement sides drains. Using these analyses a generic user-friendly risk assessment guide by which contractors may assess an aggregate prior to use is presented. A case-study is provided to illustrate some of the issues of concern. Guidelines in the risk assessment guide recommend the suitability of different physical parameters of a potential aggregate at a proposed pavement construction site for both water flow directions. If the subgrade at the site does not allow sorption by the soil to enable any contaminants in vertical flow to be below Water Quality Standards (WQS), the use of a geotextile clay liner to further increase sorption is recommended. If the concentrations of contaminants in water discharged from side drains is not below WQS for horizontal flow, guidelines determine whether the site rainfall and surface runoff allow sufficient dilution. In most situations alternative materials appear to be acceptable for use if pavement construction is on clay subgrades, with an exception of sites where the subgrades are shallower than those recommended or where they are close to areas of higher sensitivity, such as those in close proximity to protected groundwater.

The main aim of this research was to improve laboratory test methods for describing pavement foundation materials so that analytical design based on appropriate mechanical parameters of materials could be performed in practice. The study started by assessing the relevance of currently available methods to describe materials in pavement foundations and reviewing factors influencing the responses of these materials to repeated loading. Two simplified repeated load triaxial apparatuses of different sizes have been developed and their capabilities in characterizing materials in sub-base and sub grade layers have been examined. The large one is for specimens of size 280 mm diameter and 560 mm high and is suitable for full scale Department of Transport Type 1 sub-base granular materials. The small one is for cohesive soil specimens, either recompacted or undisturbed, with a diameter of 103 mm and height of 206 mm. Both apparatuses are equipped with simple loading mechanisms, user-friendly computer data acquisition systems and high precision on-sample, but easy to fix, instrumentation to monitor axial and radial displacements. A complete testing method necessitated the provision of the associated testing techniques. The whole test, including aggregate and soil preparation and testing, was designed to be conducted by one person. Development of the test procedures is detailed. Evaluation of the simplified repeated load apparatuses and the testing techniques involved testing 13 aggregate specimens and more than 26 soil specimens. Furthermore, comprehensive preliminary tests have been performed on the tested materials to provide background information which enabled results from the simplified repeated load triaxial apparatuses to be assessed in detail. For unbound granular materials, the tests included a series of particle examinations and shear box testing. For soils, besides classification tests, the soil suctions and the permanent deformation development under wheel loading were examined. To check the reliability of the two simplified facilities, tests were also carried out on pre-existing sophisticated repeated load triaxial apparatuses. Comparison of aggregate test results has enabled further understanding of the effects on resilient strain, permanent deformation and compressive strength of grading, density, shape, surface profile, surface friction and material type to be gained. Effects from waveform and frequency of load pulses were also discussed. For-soils, sufficient test results not only allowed different materials to be compared but also permitted models to describe resilient strain behaviour and permanent deformation development to be developed.