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A new facility for accurate measurement of viscosity and density of CO2-rich mixtures relevant for CO2 Capture and Storage (CCS) has been constructed. The facility includes a two-capillary viscometer with several novel solutions to enable high performance over a range between 213.15 K and 473.15 K (-60 and 200 °C) in temperature and up to 100 MPa (1000 bar) in pressure. There are currently very little data available on viscosity of liquid CO2-rich mixtures relevant for CCS, needed for instance in simulations of injection processes and reservoirs. Integrated in the setup is also a densimeter which is controlled to the same temperatures and pressures. Apart from providing density data, this enables accurate conversion between kinematic and dynamic viscosity. The total uncertainty target of the facility is 0.1 % (95% confidence level), except close to the critical point.

In the present paper the nonlinear response of fiber reinforced concrete (FRC) material is investigated in the framework of the micromechanics of heterogeneous materials. In fact, FRC is regarded as a composite with fibers embedded into a concrete matrix. A 2D unit cell, with a single fiber, subjected to tensile strain in the fiber direction is considered. To model the progressive FRC damage, i.e. the fiber debonding and pull-out and the concrete cracking, fibermatrix elastoplastic and matrix-matrix damaging interfaces are introduced. Then, numerical analyses are performed to investigate the interaction between the fiber debonding and the crack propagation, and to derive the overall macroscopic response of the FRC composite material. The numerical results obtained allow to verify the accurancy of the model adopted for the computation and its limits. Furthermore, several different analyses are performed in order to investigate on the role played by the fundamental material and geometric parameters.

Chloride ion diffusion coefficient in concrete is estimated very often by using electromigration tests, among which the Rapid Chloride Migration (RCM) test is becoming more and more popular. Nevertheless, this test receives much criticism due to lacks in its scientific background. In this paper the theoretical background of the RCM test is critically evaluated in order to show the weak points. Chloride concentration profiles measured after the migration tests give serious evidence of oversimplification of the chloride transport model adopted in the RCM test as they are substantially different from the theoretical ones. Besides this, foregoing research unveils that the chloride ion diffusion coefficients obtained from the traditional non-steady-state diffusion test and from the RCM test are correlated but not identical. As concluded in this paper, the chloride transport model currently adopted for the RCM test should be modified with the non-linear chloride binding isotherm and nonequilibrium between the concentrations of free and bound chlorides. With these phenomenon included, the diffusivity of chlorides obtained from the RCM test should have a new and correct meaning.

Chloride attack is the main cause of structural damage in reinforced concrete buildings exposed to marine environments. When a certain threshold concentration of chlorides is reached at the concrete-reinforcement interface, the corrosion of the steel rebars is initiated. A part of the intruding chloride ions will be retained by the hydration products of the binder in concrete, either through chemical binding or by physical adsorption. Therefore, chloride binding can delay the achieving of the threshold chloride concentration at the level of the reinforcement by removing chloride ions from the pore solution. Quantifying the chloride binding process helps predict the service-life of reinforced concrete structures exposed to chloride attack, and allows for a better planning of their maintenance and repair periods. Another important purpose of studying chloride binding is the design of new cement mixes that are able to slow down chloride intrusion, thus improving the durability of future marine structures. Since the hydration products of cement are responsible for the chloride binding in concrete, this study will focus on the chloride binding in hardened cement paste. A new reaction model will be used in order to predict the hydration products and their relative amounts in an OPC hardened paste. The final scope is to develop an algorithm in order to evaluate the chloride binding capacity of a given cement paste. Two main chloride binding mechanisms – through physical adsorption and through chemical reactions- were taken into account. The model also estimates the amounts of capillary and gel water, thus permitting the calculation of the maximum amount of free chloride ions in the pore solution.

The major results of Phase 2 of a project concerning the development of new design methods for wind turbine blades are summarised. Finite element models were used for studying the buckling behaviour of a box girder, tested to failure in Phase 1 of thisproject. The deformation behaviour of a box girder section subjected to transverse forces was investigated experimentally and by modelling. Buckling-driven delamination of planar specimens was studied on experimentally and by modelling. A novel approachwas proposed for the determination of mixed mode cohesive laws for large-scale crack bridging problems. The normal and shear stresses of the cohesive laws were obtained from data of the fracture resistance and the normal and tangential displacements ofthe cohesive zone. Delamination of a thin layer bonded to an elastic substrate close to corners and edges was also analysed. Results for the shape of the interface crack front and critical stress for steady-state delamination were obtained. The major results of Phase 2 of a project concerning the development of new design methods for wind turbine blades are summarised. Finite element models were used for studying the buckling behaviour of a box girder, tested to failure in Phase 1 of this project. The deformation behaviour of a box girder section subjected to transverse forces was investigated experimentally and by modelling. Buckling-driven delamination of planar specimens was studied on experimentally and by modelling. A novel approach was proposed for the determination of mixed mode cohesive laws for large-scale crack bridging problems. The normal and shear stresses of the cohesive laws were obtained from data of the fracture resistance and the normal and tangential displacements of the cohesive zone. Delamination of a thin layer bonded to an elastic substrate close to corners and edges was also analysed. Results for theshape of the interface crack front and critical stress for steadystate delamination were obtained.

The state-of-the-art in micromechanical modeling of the mechanical response of HPFRCC is reviewed. Much advances in modeling has been made over the last decade to the point that certain properties of composites can be carefully designed using the models as analytic tools. As a result, a new generation of FRC with high performance and economical viability, is in sight. However, utilization of micromechanical models for a more comprehensive set of important HPFRCC properties awaits further investigations into fundamental mechanisms governing composite properties, as well as intergrative efforts across responses to different load types. Further, micromechanical models for HPFRCC behavior under complex loading histories, including those in fracture, fatigue and multuaxial loading are urgently needed in order to optimize HPFRCC microstrcuctures and enable predictions of such material in structures under realistic loading conditions.