The primary work reported in this thesis is concerned mainly with the effects of different mixing methods and RAP materials on homogeneity and mechanical properties of hot recycled asphalt mixtures. The recycled asphalt mixture conforms to the requirement of BS 4987-1 (2005) for dense bitumen macadam size 10 mm (DBM 10 mm). The proportion of RAP in the recycled mixture is 40%. RAP materials are artificially aged and processed in the laboratory to prevent the variability of RAP gradation, bitumen content, and the origin. Laboratory RAP is also used to assure that every single RAP particle is an agglomerate of RAP aggregate and binder. The mixing procedures include Black Rock (BR), Complete Blending (CB), the SHRP procedure, and a newly developed field simulation method (FS). The primary difference between these methods is the mixing mechanism. The BR case implies the situation in which there is completely no interaction between RAP and virgin binder. On the contrary, RAP and virgin binder are fully interacted in the CB case. The mixing procedures for BR and CB cases conform to those for conventional asphalt mixtures. However, the bitumen for BR case is pure virgin bitumen. In addition, the bitumen for CB is the blend between RAP and virgin binder. The RAP/virgin binder proportion is 4/6. In the SHRP method, RAP is preheated at 110oC for two hours before being mixed with virgin aggregate and binder for 2 minutes at 130oC. In the FS method on the contrary, the mixing procedure duplicates what occurs in the asphalt mixing plant. RAP is mixed with superheated virgin aggregate (215oC) for different durations before this combination is blended with virgin bitumen for 2 minutes at 130oC. The RAP/superheated virgin aggregate mixing duration starts from short mixing time where RAP still exists at approximately original size and gradually increases until the change in RAP lump size is insignificant. Depending on the size of RAP used, RAP/superheated virgin aggregate mixing duration varies from 1 to 8 minutes. The homogeneity of hot recycled asphalt mixture is examined by using virgin binder with a different colour from that of RAP binder. The colour of virgin binder is obtained by mixing clear binder (Shell Mexphalt C 160/220 Pen) with iron oxide pigment. The proportion of pigment is 10% by weight of the binder making this binder red. The use of virgin binder with different colour from that of RAP binder helps to clearly differentiate the locations of RAP and virgin materials. Surfaces of slices cut from compacted recycled specimens are photographed by digital camera. The analysis of these surfaces in vertical order allows the locations of RAP material to be qualitatively identified in a 3D manner. Stiffness modulus values of samples for homogeneity assessment are also determined by indirect tensile stiffness test. The stiffness test is carried out in four directions along the circumference of each specimen with 45o angular increments. The experimental results show that the stiffness measurement in four directions can indicate the heterogeneity of recycled mixture. The variation in stiffness values in different measured directions will be substantial for heterogeneous mixtures and minor in the case where recycled mixtures are homogeneous. The results indicate there are mutual relations between mixing effort, homogeneity, and stiffness values of recycled asphalt mixtures. The longer mixing time will enhance the homogeneity and reduce the variation in stiffness values of recycled mixture. In addition, as more RAP and virgin binder are incorporated, the stiffness values of recycled mixture generally increase once the mixing time is extended. As the clear binder is dyed red by 10% by weight of iron oxide, the proportion of the pigment certainly alters the flow characteristic of binder. This might affect the mixing process and rejuvenating effect between virgin and aged binder. Therefore, the effects of mixing methods and RAP sizes on mechanical performance of hot recycled asphalt mixtures are further investigated using normal straight run bitumen 160/220 Pen as virgin binder. The assessment indicators include stiffness modulus, resistance to fatigue damage, and resistance to permanent deformation. The experimental results indicate that the conventional laboratory mixing method (SHRP) tends to overestimate the mechanical properties of recycled asphalt mixture. The long RAP preheating time that never exists in the industry coincidentally enhances the reaction between RAP and virgin binder. The long RAP preheating time also slightly alters the properties of RAP binder. For the FS method, the increase in mixing duration significantly improves the homogeneity level of recycled mixtures. The homogeneity level is also substantially affected by the size of RAP material. For the same mixing effort, the mixtures comprised of small RAP are generally more homogeneous than those made from larger RAP. The more homogeneous the mixture, the more interaction between RAP and virgin binder. Therefore, recycled mixtures become stiffer and have better resistance to permanent deformation and fatigue failure. A slightly linear increase in stiffness can result in an exponential increase in fatigue life of the recycled mixture. The mechanical properties including stiffness modulus, resistance to fatigue damage, and resistance to permanent deformation of hot recycled asphalt mixtures are not similar to those of the BR or CB mixtures, even at the favourable condition where RAP is preheated for 2 hours at 110oC in the SHRP method and 8 minutes mixing duration in the FS method. This implies that RAP does not act as Black Rock. In addition, the assumption that RAP and virgin binder are fully blended also never exists in the recycled asphalt production process.

This thesis describes the investigation and development of damage modelling techniques for woven long glass fibre reinforced polypropylene matrix composites. The objective of the work was to develop and validate predictive models for the intralaminar damage behaviour of these materials, with the aim of applying the results to an industrial demonstrator component. Two damage modelling methods were investigated. The first, based on ply-level failure criteria and implemented in an implicit finite element code, was developed and validated using a range of coupon tests for a balanced weave 60% weight fraction commingled glass/polypropylene composite. The second method utilised a model previously implemented in the commercial explicit finite element code, PAMCRASH. This model was calibrated and validated using the same coupon tests as the first model. The models were subsequently used to simulate an industrial demonstrator component, during a two-phase design and development programme. The demonstrator, an automotive side intrusion beam, was designed and predictively modelled using the two damage modelling techniques investigated. Finally, the composite component was compared to a steel side intrusion beam, using a quasi-static vehicle test to a current legislative standard. This test showed comparable performance in terms of strength and stiffness for the two beams. It was concluded that the implicit finite element damage modelling technique can account for the damage and failure modes observed in a woven glass fibre reinforced polypropylene composite, but is limited when considering high levels of material nonlinearity and damage development, due to the stability of the implicit finite element method. It was also concluded that the explicit finite element technique was more suited to the simulation of damage development in thermoplastic matrix composite components, although the research showed that the model investigated was limited when considering shear damaging behaviour in a woven fibre reinforced composite.

The study investigates experimentally and theoretically the behaviour of an internal precast concrete beam-column connection, where both the column and beam are discontinuous in construction terms. The aim was to modify the behaviour mechanisms within the connection zone by introducing a beam hogging moment resistance capacity under dead loads and limiting the damage within the connection. This is to offer permanent dead load hogging moments that could counterbalance any temporary sagging moment generated under sway loads, enhance the rotational stiffness, balance the design requirements for the beam-end and beam mid-span moments, provide efficient continuity across the column, and reduce the deflection at the beam mid-span. Three full-scale beam-column connection tests subjected to gravity loads were conducted taking the connection reinforcement detail as the main variable. The configuration of the three main interfaces within the connection was based on the experimental results of small-scale tests. The results of the full-scale tests showed that, by using the strong connection concept, it was possible to produce equivalent monolithic behaviour, control the crack width within the connection zone, and force the final damage to occur outside of this zone, which comprises the interfaces and parts of the adjoining elements. The strong connection consisted of using additional short steel bars crossing the connection at the top of the beam, horizontal U-shaped links at the beam-ends, and additional column links. In addition, the experimental programme included two full-scale tests to investigate the behaviour of the connection under sway loads using two different connection reinforcement details. The results of this study showed that the proposed modification in the reinforcement details was able to mobilise the beam sagging moment through the dowel action of the column main bars but it was also accompanied by large relative beam-column rotations (low rotational stiffness). The evaluation of the behaviour of the connections was carried out by incorporating the experimental rotational stiffnesses in semi-rigid frame analyses using the ANSYS software package and a Visual Basic program based on the conventional semi-rigid analysis approach. In addition, a simplified technique has been validated against these two methods to replicate the semi-rigid behaviour. In the same respect, the study is proposing a new approach for classifying precast concrete beam-column connections as rigid by relating the connection fixity factor with the moment redistribution. It has been shown that the connection could be classified as rigid if the fixity factor is not less than 0.73 and the available moment redistribution from the midspan to the supports is not less than the required moment redistribution resulting from semi-rigid frame analysis. In the theoretical part, an analytical tool has been calibrated to predict the rotational stiffness of the specimens with semi-rigid behaviour under gravity loads. The model showed a reasonable agreement with the experimental results. To help the modelling, two pull-out tests were conducted to determine the bond-slip relation of steel bars embedded in cement-based grout. Moreover, a finite element numerical simulation model using the ANSYS software package was carried out to replicate the experimental results of the semi-rigid specimens tested under gravity loads. In spite of providing results close to experimental values prior to yielding, the FE model was not able to predict the failure mode and consequently the correct ultimate load. This is due to the simplified way of modelling the interaction between the corrugated sleeves and the surrounding concrete as perfect bond. The research concludes that the precast beam-column connection investigated in the current study can be treated as an emulative monolithic connection under gravity loads through using the strong connection concept; however, it is not suitable to resist beam net sagging moments. Besides, the study concludes that to consider a precast concrete beam-column connection as rigid, it is required to correlate the fixity factor with the moment redistribution.

Wind action is particularly important for tall buildings, both in providing a significant contribution to the dynamic overall loading on the structure and by affecting its serviceability. Whereas low and medium-rise buildings are fairly rigid, tall structures are characterized by a greater flexibility and a lower natural frequency, which is more likely to be in the frequency range of wind gusts. In addition, wake effects, such as vortex shedding, can become a significant problem for flexible structures when the vortex shedding frequency is close to the natural frequency of the building. The aim of the present thesis is to assess the validity of commercial CFD codes for modelling the wind flow around a high-rise building, including the consideration of the coupled dynamic response of the building to turbulent wind loading. Three intermediate objectives are set. The first is to develop a tool to couple fluid and structure in a sequential manner. The equations for the air flow are solved using the commercial CFD program ANSYS-Fluent. The response of the structure is found from solving the structural response with a modal approach, the response in each vibration mode being treated as a SDOF problem. This fluid-structure interaction tool is applied to model a 180 m building, allowed to move in the across wind direction. The second objective is to investigate and find a method to generate fully turbulent inflow for LES in order to reproduce an accurate wind spectrum. The chosen method is tested and validated in an empty fetch. Ultimately, both tools are brought together and applied to model a 180 m building, which is allowed to bend in the along wind and across wind directions. Finally, the third intermediate objective brings together the tools developed in the first and second intermediate objective to model the dynamic response of a 180 m building to dynamic wind loading, within a turbulent inflow, using LES.

This thesis presents a crystallographic orientation determination technique which is based on a laser ultrasonic method: spatially resolved acoustic spectroscopy (SRAS). Surface acoustic waves (SAW) propagate on a solid surface with a phase velocity that is frequency independent, but which varies with the crystallographic orientation. By comparing the SRAS results with the calculated SAW velocities, the orientation of crystal can be determined. The SRAS technique allow the SAW velocity to be recorded in two slightly different approaches. According to the formula v=λf, the velocity v can be obtained by varying the k-vector (λ) or frequency f of the wave while the another multiplier is fixed. K-SRAS is implemented by firing a laser beam with a fixed intensity modulation frequency through a spatial light modulator (SLM); the SAW velocity is determined by varying the fringe spacing of the SLM image. F-SRAS uses a broadband (sharp pulse) laser, the beam passes through a chrome photomask with fixed fringe spacing, and the peak frequency is used to determine the SAW velocity. Scans are performed on single or multiple-grain titanium alloy, aluminium and nickel samples by both methods. The contrast of the velocity maps give adequate information of grain size and location. A SAW velocity model is developed according to the elastic constants and mass density of the material. The orientation of crystals can be determined by comparing the SRAS results and the SAW velocity model. The SAW velocities in different propagation directions are measured on nickel, aluminium and titanium α samples with known orientations, and agree well with the predicted velocities from the model. An overlap function is introduced as a search algorithm to link the SRAS results to the SAW velocity model. The results are compared with measurements taken using the Laue back-reflection technique; they gave very close crystallographic orientation with acceptable error within the industrial limit. At the end of the thesis, consideration is given to further research in the acoustic modelling and data processing algorithms that would improve the technique in the future.

This thesis examines the effects that containerisation had on the growth in world trade between the years 1962 and 1990. Containerisation is a technological change that arises from shipping goods via containers rather than through the traditional break-bulk method which characterised international shipping since antiquity. This thesis makes many contributions to the literature. This is the first quantitative and econometric study into the effects of containerisation in economics. We collect data from a specialist business publication and construct container variables which are used for the first time in economics. We also use a scientific classification from 1968 to classify products as containerisable or non-containerisable. Another contribution is that the econometric models employed in this thesis allow for a "horse race" between the technology variable and the policy variables: free trade agreements, General Agreement on Tariffs and Trade membership and currency unions. We make use of the cross-sectional and time series variation available to us in the adoption of the technology across 157 countries to identify the effects of containerisation on world trade. We employ several specifications and try different trade flow dimensions to pin down the right way to model containerisation. In doing so, we deal with several econometric problems that arise in similar econometric studies such as omitted variable bias and endogeneity bias. The effects of containerisation are felt 10 to 15 years after bilateral adoption of the technology. We estimate that containerisation led to an increase of 380% in North-North containerisable trade 10 to 15 years later. We find no evidence for endogeneity in this specification and we can be confident to make a causal statement. We also find evidence that containerisation affected North-South trade the most, followed by North-North and then South-South containerisable trade although we cannot be as confident about making causal statements in the case of North-South and South-South trade. The evidence is however suggestive of strong effects on containerisable trade in the two subsamples. In all cases, the effects of containerisable are found to be multiple times the size of the effects of the individual policy variables - 2 to 10 times as large depending on the subsample and the variable in question.

Modern demands in power generation call for higher efficiencies from every area of the power plant. One aspect of this is a drive to increase plant operating temperatures placing higher demand on structural materials. P91 and P92 are two steels commonly used in steam pipes. In order to accurately predict the service lifetime of components, mechanical properties at operating temperatures are critical. In particular properties of material around weld fusion joints are of interest as it is in these regions where failures occur. Conventional techniques such as Vicker’s hardness testing and uniaxial tensile testing are used to characterise the mechanical properties and creep behaviour of bulk materials. These techniques are often used to determine the properties of P91 and P92 parent and weld materials, the limitation of these techniques is that they require large volumes of material. They are therefore unable to determine differences in properties through the heat affected zone of the parent material which is typically only a few millimetres across. Nanoindentation is a technique which offers a potential solution to this problem. It was developed in order to examine the properties of thin films and small material volumes. In recent years several approaches have been developed to perform nanoindentation experiments at elevated temperature. These approaches have been examined in order to establish which provides the best thermal stability for high temperature nanoindentation measurements. This technique has then been used to perform high temperature nanoindentation experiments to determine the mechanical properties and creep behaviour of P91 and P92 steel. The correlation between nanoindentation measurements on bulk materials and those obtained using conventional methods is examined. In particular the significance of creep stress exponents calculated from nanoindentation dwell data is discussed. Nanoindentation is then used to characterise the heat affected zone of a weld, giving clear indications of the effects of microstructural differences on the material properties.

Plant fibres, perceived as environmentally sustainable substitutes to E-glass, are increasingly being employed as reinforcements in polymer matrix composites. However, despite the promising technical properties of cellulose-based fibres and the historic use of plant fibre composites (PFRPs) in load-bearing components, the industrial uptake of PFRPs in structural applications has been limited. In developing PFRPs whose mechanical properties are well-characterised, optimised and well-predicted, this thesis addresses the question: Can PFRPs replace E-glass composites (GFRPs) in structural applications? Ensuring that the highest reinforcement potential is exploited, this research examines the mechanical properties of aligned PFRPs based on bast fibre yarns/rovings and thermoset matrices. Although aligned GFRPs are found to outperform aligned PFRPs in terms of absolute mechanical properties, PFRPs reinforced with flax rovings exhibit exceptional properties, with a back-calculated fibre tensile modulus of up to 75 GPa and fibre tensile strength of about 800 MPa. To identify the processing window which produces composites with useful properties, the minimum, critical and maximum fibre volume fraction of PFRPs have been determined, and compared to that of synthetic fibre reinforced composites. The effect of fibre volume fraction on the physical and tensile properties of aligned PFRPs has also been investigated. Furthermore, micro-mechanical models have been developed and experimentally validated, to reliably predict the effect of (mis)orientation, in the forms of yarn twist/construction and off-axis loading, on the tensile properties of aligned PFRPs. To provide a complete set of fatigue data on aligned PFRPs, the effect of various composite parameters on PFRP cyclic-loading behaviour has been illustrated through S-N lifetime diagrams. A constant-life diagram has also been generated to enable the fatigue design and life prediction of a PFRP component. At each stage, the fatigue performance of PFRPs has been compared to that of GFRPs. Finally, in directly addressing the main theme, this thesis adopts a novel comparative case study approach to investigate the manufacture and mechanical testing of full-scale 3.5-meter composite rotor blades (suitable for 11 kW turbines) built from flax/polyester and E-glass/polyester. The study claims that under current market conditions, optimised plant fibre reinforcements are a structural, but not low-cost or sustainable, alternative to conventional E-glass reinforcements.

Instrumented indentation techniques at micro or nano-scales have become more popular for determining mechanical properties from small samples of material. These techniques can be used not only to obtain and to interpret the hardness of the material but also to provide information about the near surface mechanical properties and deformation behaviour of bulk solids and/or coating films. In particular, various approaches have been proposed to evaluate the elastic-plastic properties of power-law materials from the experimental loading-unloading curves. In order to obtain a unique set of elastic-plastic properties, many researchers have proposed to use more than one set of loading-unloading curves obtained from different indenter geometries. A combined Finite Element (FE) analysis and optimisation approach has been developed, using three types of indenters (namely, conical, Berkovich and Vickers), for determining the elastic-plastic material properties, using one set of ‘simulated’ target FE loading-unloading curves and one set of real-life experimental loading-unloading curves. The results obtained have demonstrated that excellent convergence can be achieved with the ‘simulated’ target FE loading-unloading curve, but less accurate results have been obtained with the real-life experimental loading-unloading curve. This combined technique has been extended to determine the elastic and visco-plastic material properties using only a single indentation ‘simulated’ loading-unloading curve based on a two-layer viscoplasticity model. A combined dimensional analysis and optimisation approach has also been developed and used to determine the elastic-plastic material properties from loading-unloading curves with single and dual indenters. The dimensional functions have been established based on a parametric study using FE analyses and the loading and linearised unloading portions of the indentation curves. It has been demonstrated that the elastic-plastic material properties cannot be uniquely determined by the test curves of a single indenter, but the unique or more accurate results can be obtained using the test curves from dual indenters. Since the characteristic loading-unloading responses of indenters can be approximated by the results of dimensional analysis, a simplified approach has been used to obtain the elastic-plastic mechanical properties from loading-unloading curves, using a similar optimisation procedure. It is assumed that the loading-unloading portions of the curves are empirically related to some of the material properties, which avoids the need for time consuming FE analysis in evaluating the load-deformation relationship in the optimisation process. This approach shows that issues of uniqueness may arise when using a single indenter and more accurate estimation of material properties with dual indenters can be obtained by reducing the bounds of the mechanical parameters. This thesis highlights the effects of using various indenter geometries with different face angles and tilted angles, which have not been covered previously. The elastic-plastic material parameters are estimated, for the first time, in a non-linear optimisation approach, fully integrated with FE analysis, using results from a single indentation curve. Furthermore, a linear and a power-law fitting scheme to obtain elastic-plastic material properties from loading-unloading indentation curves have been introduced based on dimensional analysis, since there are no mathematical formulas or functions that fit the unloading curve well. The optimisation techniques have been extended to cover time-dependent material properties based on a two-layer viscoplasticity model, has not been investigated before.

Discontinuous fibre composites are under increasing investigation for structural and semi-structural components as they are easily automated, making it possible to remove costly hand labour based steps typically associated with advanced fibre reinforced composites. Directed fibre preforming (DFP) is one possible process which has several advantages when compared with competing techniques. Low material and process costs coupled with short cycle times means the process is suited to medium volume production (typically <10,000 ppa). Predicting mechanical performance remains a major obstacle to industrial adoption however, due to the stochastic nature of fibre distribution. This is of particular importance for structural applications where minimum property requirements and a greater certainty of performance must be achieved. This thesis employs a stochastic macroscale modelling approach to predict fibre locations during the reinforcement deposition stage. This is achieved through process characterisation studying the effects of key microstructural and process-specific parameters on fibre distribution and orientation. The proposed DFP simulation software can generate realistic fibre networks for complex three-dimensional component geometries providing feedback on preform quality. This information is used to optimise the preform structure via process input parameters such as robot trajectory and material properties with validation tests conducted to assess model accuracy. An interface between the simulation software and commercial finite element code facilitates mechanical property analysis for full-scale components using realistic load cases. The complete software package is intended to streamline the route to manufacture for DFP processes from a conceptual design stage.