Test methods for concrete durability indicators

Durability of concrete structures is primarily dependent on the environmental influences, i.e. the penetration of aggressive substances in the structural element from the environment. Penetrability is an important durability indicator of concrete and by specifying different classes of penetrability of concrete it should be possible to design a structure with the required resistance to environmental loads. This chapter covers descriptions of the available and commonly applied in situ and laboratory, non-invasive and semi-invasive test methods for evaluating concrete penetrability properties.

Principles of the performance-based approach for concrete durability

In general, design approaches for durability can be divided into prescriptive design concepts and performance-based design concepts.

The Complete Works of John Milton: Volume III: The Shorter Poems (826pp.)

Stephen B. Dobranski, Milton Quarterly 49.3 (October, 2015), 181-4:

'By addressing classical and neo-Latin works with which Milton's poems appear to engage, Haan has pursued something unattempted yet. Her erudite and engaging commentary on the Poemata is the most extensive and impressive that I have encountered in any edition ... Haan's discussion of Milton's Poemata - including the Testimonia, the one Italian and four Latin encomia by the poet's acquaintances published in 1645 and 1673 - is remarkably detailed and well-researched. In these sections, readers learn, for example, how Milton's Epitaphium Damonis borrows from both classical writers (Theocritus, Moschus) and contemporary models (Castiglione, Zanchi) while transcending all of them through a pattern of resurrection motifs. Or, readers can discover affinities between Milton's lament on the death of the Bishop of Ely and a poem by the Italian humanist Hieronymo Aleander, Jr., or learn about the connections between Milton's Elegia Quinta and George Buchanan's Maiae Calendae ... The Shorter Poems is a scholarly achievement of the highest order.'

Noam Reisner, Review of English Studies 65 (2014), 744-5:
‘Haan shines with her Neo-Latinist expertise by offering a vivid separate introduction to the Latin poems, which sets up Milton’s poemata specifically within the Neo-Latin contexts of the seventeenth century, thereby dispelling any remaining view of these poems as juvenilia (a view which results from reading the poems chronologically). … The present volume will instantly establish itself as the definitive resource for any reader interested in Milton’s shorter poems, and it is scarcely imaginable that it will ever be eclipsed or be in need of replacing. Its contribution is important in all areas, especially in providing for the first time in a single volume truly valuable documents which can teach us a lot more about Milton’s poetic development than simply reading the poems in chronological sequence. But perhaps, this edition’s greatest achievement is the way in which it succeeds in giving Milton’s Latin poems the pride of place they have long deserved as fully integral to Milton’s complete poetic imagination. Haan’s specific achievement in this regard is less in updating the translations than in providing a different context through which to look at the Latin poems themselves. Haan’s detailed commentaries set the Latin poems in a completely fresh light which looks beyond the obvious classical references and allusions, noted by Carey and many other editors, to Milton’s complex engagement with the Neo-Latin literary culture of his time. It is this aspect of the volume, more than anything else, which vindicates its essentialness.'

Concrete damage plasticity model for modeling FRP-to-concrete bond behavior

The technique of externally bonding fiber-reinforced polymer (FRP) composites has become very popular worldwide for retrofitting existing reinforced concrete (RC) structures. Debonding of FRP from the concrete substrate is a typical failure mode in such strengthened structures. The bond behavior between FRP and concrete thus plays a crucial role in these structures. The FRP-to-concrete bond behavior has been extensively investigated experimentally, commonly using a single or double shear test of the FRP-to-concrete bonded joint. Comparatively, much less research has been concerned with numerical simulation, chiefly due to difficulties in the accurate modeling of the complex behavior of concrete. This paper presents a simple but robust finite-element (FE) model for simulating the bond behavior in the entire debonding process for the single shear test. A concrete damage plasticity model is proposed to capture the concrete-to-FRP bond behavior. Numerical results are in close agreement with test data, validating the model. In addition to accuracy, the model has two further advantages: it only requires the basic material parameters (i.e., no arbitrary user-defined parameter such as the shear retention factor is required) and it can be directly implemented in the FE software ABAQUS.

Finite element modelling of FRP-to-concrete bond behaviour using the concrete damage plasticity theory combined with a plastic degradation model

The technique of externally bonding fibre reinforced polymer (FRP) composites has been becoming popular worldwide for retrofitting existing reinforced concrete (RC) structures. A major failure mode in such strengthened structures is the debonding of FRP from the concrete substrate. The bond behaviour between FRP and concrete thus plays a crucial role in these structures. The FRP-to-concrete bond behaviour has been extensively investigated experimentally, commonly using the pull-off test of FRP-to-concrete bonded joint. Comparatively, much less research has been concerned with the numerical simulation of this bond behaviour, chiefly due to difficulties in accurately modelling the complex behaviour of concrete. This paper proposes a robust finite element (FE) model for simulating the bond behaviour in the entire loading process in the pull-off test. A concrete damage plasticity model based on the plastic degradation theory is proposed to overcome the weakness of the elastic degradation theory which has been commonly adopted in previous studies. The model produces results in very close agreement with test data. © Tsinghua University Press, Beijing and Springer-Verlag Berlin Heidelberg 2011.

Closure to “Concrete Damage Plasticity Model for Modeling FRP-to-Concrete Bond Behavior” by Y. Tao and J. F. Chen

The authors appreciate the discusser’s interest in the original paper and for the valuable discussion, which provides the opportunity to clarify and reiterate a few points made in the original paper. The comments and questions raised by the discusser are addressed in the following sections.