The research explores aspects of road surface measurement and monitoring, targeting some of the main challenges in the field, including cost and portability of high-speed inertial profilers. These challenges are due to the complexities of modern profilers to integrate various sensors while using advanced algorithms and processes to analyse measured sensor data. Novel techniques were proposed to improve the accuracy of road surface longitudinal profiles using inertial profilers. The thesis presents a Half-Wavelength Peak Matching (HWPM) model, designed for inertial profilers that integrate a laser displacement sensor and an accelerometer to evaluate surface irregularities. The model provides an alternative approach to drift correction in accelerometers, which is a major challenge when evaluating displacement from acceleration. The theory relies on using data from the laser displacement sensor to estimate a correction offset for the derived displacement. The study also proposes an alternative technique to evaluating vibration velocity, which improves on computational factors when compared to commonly used methods. The aim is to explore a different dimension to road roughness evaluation, by investigating the effect of surface irregularities on vehicle vibration. The measured samples show that the drift in the displacement calculated from the accelerometer increased as the vehicle speed at which the road measurement was taken increased. As such, the significance of the HWPM model is more apparent at higher vehicle speeds, where the results obtained show noticeable improvements to current techniques. All results and analysis carried out to validate the model are based on real-time data obtained from an inertial profiler that was designed and developed for the research. The profiler, which is designed for portability, scalability and accuracy, provides a Power Over Ethernet (POE) enabled solution to cope with the demand for high data transmission rates.

The aim of this research has been to characterise the behaviour of a variety of locally available naturally occurring and artificially prepared aggregates in a form suitable for use in pavement analysis. The materials chosen are commonly used in developing countries as capping layers, subbases and road bases with a maximum size of 38 mm. A review of previous work is presented and details of some improved, simple and practical new experimental techniques developed for both static and dynamic testing of materials are included. The maximum proportion of volume occupied by solids (MPVS) for a granular mixture when compacted to refusal in a dry state was taken as a measure of laboratory compactability. Also the water required to saturate at this MPVS has been found to correspond with the optimum moisture content (OMC). Significant correlations were obtained between MPVS values against coefficient of uniformity on logarithmic scale, MPVS values against fines content (fraction passing 0.075 mm sieve) and MPVS values against angularity number. These correlations indicate that MPVS values obtained in the dry state provide a reliable measure of the combined effects of particle shape, texture, grading and degradation upon compactability. Laboratory testing of materials has been carried out according to the following modes of test: California Bearing Ratio (CBR), Modified Bearing Ratio (MBR), large direct shear box, simple impact hammer test (as developed in Australia) and in both dynamic bearing and triaxial apparatus capable of applying repeated stress in the axial directions. To simulate actual pavement conditions more closely, tests were carried out both on wet and dry mixes using three different gradings namely a normal Fuller grading, a coarser 'lower limit of DT ' grading and a finer Lees' grading.

The lifespan of asphalt surfacing materials can vary from a very short duration, when temporary surfacing is considered, to up to 25 years for permanent surfacings. Throughout their lifespan the surfacings are expected to contribute to the provision of adequate levels of friction. The purpose of this research is to examine the variation of friction characteristics of road surfacing materials with time. The asphalt industry has undergone considerable change over the past two decades. This has seen the dominance of hot rolled asphalt and bituminous macadams (now asphalt concrete) being replaced by a spectrum of asphalt mixes specifically designed to offer a wider range of enhanced characteristics. Skidding resistance has remained as a priority requirement. Research has highlighted that there are distinct periods during the life of asphalt road surface materials. The existing standards are based on an equilibrium period during which there is seasonal variation with an overall downward trend to a value at which the surface warrants investigation prior to possible resurfacing or some other type of treatment. For some materials, there is an initial period of lower than expected skidding resistance found to last from a number of days, weeks to months and is termed early life. The majority of laboratory studies undertaken in this thesis were designed to reflect either real or hypothetical scenarios that could be encountered on an in-service highway surface. The programme of work considered the development of skid resistance for a range of surfacing materials from initial compaction until they have reached their equilibrium and are failing for different reasons. There were distinct generic relationships and the development of friction properties has different timelines depending on factors such as aggregate type, asphalt type, bitumen type and stressing conditions. The findings of the research will necessitate the revision of current Irish standards that will bring it closer in line with other European countries. This will probably involve the use of smaller stone size mixes and lowering the requirements for texture depth. It is anticipated that the improved understanding of the implications of poor practise will lead to better quality road surfaces in Ireland.

No description available.

No description available.

Efficient road networks are an integral aspect of the transport infrastructure of any modern economy and sound pavement design, along with effective maintenance programmes, are crucial to the continued quality and value of these assets. Polymer modification of the asphalt is frequently used to enhance the pavement durability performance. However, the benefits of polymer modification are not always clear to the designing engineer. Laboratory tests to assess asphalt performance often require large quantities of material, highly specialised test equipment and considerable amounts of time. Whilst the advantages of polymer modification on deformation resistance are well accepted, its impact on cracking and fatigue is less well defined. This research was therefore undertaken to quantify the effect of polymer modification on the cracking and fatigue performance of asphalt, and to develop methods to minimise the time and materials required to perform the laboratory assessments. A novel technique to analyse the performance of full asphalt mixtures utilising a standard laboratory dynamic shear rheometer (DSR) was developed using very small sample sizes. The technique was validated by comparing the results to existing testing geometries, with the new method shown to depict the viscoelastic behaviour of the asphalt. The asphalt’s fundamental fracture mechanics properties were investigated via the semi circular bending geometry, with the improved performance of the polymer modified asphalts in terms of fracture toughness and strain energy release rate demonstrated. A crack growth law based on the generalised J-integral was developed and used to determine characteristic material parameters which were used to predict pavement service life. Crack propagation of the semi-circular bending geometry under monotonic loading was modelled using the Extended Finite Element Method with the time dependent viscoelastic properties within the model determined using the small sample size technique, and modelled using a fractional viscoelastic element. ii The calibrated model was used to predict the load-displacement behaviour of specimens, and the improved crack resistance of the polymer modified asphalts verified. Binder fatigue behaviour was analysed using the DSR and the improved damage resistance of increasingly polymer modified binders verified. Asphalt fatigue was assessed using traditional large scale trapezoidal two point bending, cyclic semi-circular bending and small specimen sized tests on the DSR with the effect of polymer modification evaluated. Viscoelastic Continuum Damage (VECD) theory was successfully applied to the results with the potential for significant reductions in test durations using this approach demonstrated.

No description available.

An effective pavement management system (PMS) is one that is guided by a software program that ensures that all pavement sections are maintained at adequately high serviceability levels and structural conditions with a low budget and resource usage, without causing any significant negative effect on environment, safe traffic operations and social activities. PMS comprises of section classification; performance prediction; and optimisation for decision-making. For section classification, this research presents a fuzzy inference system (FIS), with appropriate membership functions for section classifications and for calculating the pavement condition index (PCI). The severity and extent of seven distress types (alligator cracking, block cracking, longitudinal and transverse cracking, patching, potholes, bleeding and ravelling) were used as fuzzy inputs. The result showed a good correlation for fuzzy model. A sensitivity analysis showed a pavement crack has the greatest influence on section classification compared to the other distress types. A novel network level deterministic deterioration model was developed for flexible pavement on arterial and collector roads in four climatic zones considering the impact of maintenance, age, area and length of cracks, and traffic loading. The prediction models showed good accuracy with high determination coefficient (R2). The cross-validation study showed that the models for arterial roads yield better accuracy than the models for collector roads. A sensitivity analysis showed that the area and length of cracks have the most significant impact on the model performance. A novel discrete barebones multi-objective particle swarm algorithm was applied for a discrete multi-objective problem. Conventional particle swarm optimisation (PSO) techniques require a manual selection of various control parameters for the velocity term. In contrast, the bare-bones PSO has the advantage of being velocity-free, hence, does not involve any parameter selection. The discrete barebones multi-objective PSO algorithm was applied to find optimal rehabilitation scheduling considering the two objectives of the minimisation of the total pavement rehabilitation cost and the minimisation of the sum of all residual PCI values. The results showed that the optimal maintenance plan found by the novel algorithm is the better than found by conventional algorithm. Although the results of performance metrics showed that the both algorithms perform on a par, the novel algorithm is clearly advantageous as it does not need parameter selection.

The aim of this study was to break through current limits with cement substitutes in concrete paving block and introduce high levels of cementitious constituents. As well as meeting the current strength and durability requirements stated in BS EN 1338:2003 the study reported on the effect of materials variability and leaching properties. The cementitous materials used to replace Portland cement (PC) were Pulverised Fuel Ash (PFA also known as Fly Ash), Ground Granulated Blast Furnace Slag (GGBS), Metakaolin (MK), Silica fume (SF), Glass Powder (GP), Basic Oxygen Slag (BOS) and By Pass Dust (BPD). The first phase of the study analysed 11 groups of ternary cement paste blends using Minitab, a statistical programme to help determine mix designs and optimised mix. Analysis of ternary cement pastes in the first phase concluded that mixes containing GGBS over PFA produced greater strengths at early ages. Mixes confirmed that PC-GGBS-GP provided good strengths due to the SiO2 content within GP providing secondary CSH gel. PC-GGBS-BPD provided good strengths due to SO3 within BPD activating the GGBS through sulphates. The best results in forms of strength were found in PC-GGBS-SF and PC-GGBS-BOS ternary pastes. The fine particles along with the high SiO2 content of SF provided greater pozzolanic reactivity and a greater matrix densification. Fourteen of the best mixes were then taken into the second phase. This is when concrete paving blocks were made from these mixes with the method that was developed at Coventry University. The two mixes with the greatest splitting tensile strength consisted of varying levels of PC-GGBS-SF and were known as the candidate mixes. The durability criteria set out in BS EN 1338:2003 was met, however the minimum strength requirement was not. The candidate mixes were still chosen to be produced in the factory as the manufacturing and curing procedure in the factory was more effective and efficient in comparison to the laboratory procedure. The site trial successfully achieved the minimum requirements for the mechanical properties and durability performance stated in BS EN 1338:2003 and reduced the cement content of concrete paving blocks by 40% wt of PC, with a ternary blend consisting of 60% PC, 25% GGBS and 15%SF. Analysis of material variability was conducted on PFA (regulated commercially available replacement) and BPD (replacement waste material). Results showed that when using regulated commercially available cementitious constituents the chemical composition of the material should be within a given range (For replacement by weight of 10%, 20%, 30%, difference in main oxide should be no greater than 1%, 2.5% and 3.5% respectively) and for the waste material the chemical composition (Limits as stated for regulated commercially available material) as well as fineness (Replacement by weight of 5% and 10% should not have a variability in average particle size of more than 15μm) should be within a range. The two candidate mixes were finally tested for their leaching properties against a leachate that was derived from used oil concentrations. The increase in permeability with the use of GGBS and SF lead to the block absorbing less of the leachate in comparison to the control mix. The study set out to introduce high levels of cementitious constituents in concrete paving blocks. Although it is known that high levels of replacement would cause deterioration, this was done in order for the study to create a database in which the company could refer to and determine which constituents performed well and what the maximum level of replacement could be. The study successfully replaced PC by 40% with 25% GGBS and 15% SF. With blocks actually producing greater strengths than the control mix (100% PC) at 28 days and meeting all the minimum requirements that were set out in BS EN 1338:2003.

Renewable energy combined with energy efficiency can offer a viable and influential solution to minimise the harmful consequences of both fossil fuel depletion and increases in the cost of power generation. However, in most cases renewable energy technologies require high initial investments that may deter potential users. Pavement Energy Systems (PES) potentially offer a low-cost solution to sustainable and clean energy generation by utilising the thermo-physical properties and design features of new/existing pavement infrastructure. Within the PES, fluid-filled pipes are buried in the pavement at varying depths and transfer heat to and from the surrounding material, for application as a solar energy collector and/or thermal storage media. The fluid in the pipes can absorb/reject heat to the pavement and deliver useful energy to nearby buildings as well as benefiting the pavement structure and pavement users (in terms of reduced rutting, winter road maintenance, etc.). A significant advantage of such systems is that the pipes can be installed within pavements that are already needed for structural reasons and need not to be installed as single-function elements, as do conventional thermal utilisation systems. In this project, the effect of pavement materials and layer design optimisations on the performance of PES was investigated both theoretically and experimentally. The thermo-physical properties and load-bearing performance of concrete and asphalt pavements, consisting of conventional and unconventional components, were determined. In addition, pseudo 3D transient explicit finite-difference software was developed for modelling and performance analysis of the PES under various operating conditions and configurations. This software is capable of predicting the outlet fluid temperature and temperature distributions within the pavement structure. Furthermore, large-scale physical models of the PES were designed and constructed to compare the performance of the thermally modified pavement structures with those of conventional ones and also to validate the model. The physical model consisted of copper pipes embedded in pavements which were irradiated (causing surface heating) using halogen lamps. The results of thermo-physical optimisation of pavement materials, coupled with mechanical testing, showed that it was possible to achieve a wide range of thermally-modified pavements that can also meet the rigorous functional requirements of an airfield pavement. The experimental comparison between the thermally modified and unmodified concrete pavements revealed that there was potential to enhance both the heat collection and storage capability of concrete pavement structures. In addition, the model’s predicted temperatures in concrete pavements were in good agreement with the experimental ones with a mean error of less than 1°C. A similar comparison on asphalt pavements showed that although the surface temperature was lowered by asphalt modification, there were significant discrepancies between the measured and predicted surface temperatures for both modified and unmodified pavements. Further study was conducted on the pipe/pavement interface using X-Ray Computed Tomography (XRCT). The X-ray images revealed improper bonding between the pavement’s matrix and the pipe that was evidenced by the presence of air voids accumulation around the pipe perimeter, and could explain the significant discrepancy in the modelled temperatures. Furthermore, the validated model was used, for genuine temperature patterns, to simulate the relative influence of both the thermo-physical properties of pavement materials and the pavement layer sequences on the performance of the PES and to determine the implications for pavement design. It was concluded that the enhancements could allow pipes tobe installed deeper within the pavement without having any negative effect on their thermal performances. Pipe installation deeper in the pavement is expected to reduce ‘reflective cracking' under traffic loading as well as enabling future resurfacing of the pavement without damaging the pipe network.