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In this contribution, the modelling of salt crystallization-induced damage in layered porous materials (such as masonry strengthened with composites, glazed earthenware, etc.) is addressed through a staggered multiphysics method. A staggered interchange of data is pursued between a multiphase model (crystallization pressure) and a macro-scale nonlinear mechanical model (material damage). Such method is preliminary applied to layered porous materials through a simple benchmark. Accordingly, the effects of layers with different properties on the crystallized salt distribution and damage pattern are highlighted.

Over the decades, innovative techniques have been introduced and developed in the building heritage which make use of composite materials whose main objectives are bending and shear reinforcement, increasing ductility and limiting cracks. The use of composite materials with steel, carbon, glass and aramid fibers are already codified in the technical standards, now the challenge is the use of more sustainable materials. This paper focuses on a simple and effective bamboo fibers reinforcement of structural and non-structural commercial products such as mortar and plaster with different mechanical characteristics, trying to improve ductility without worsening their strength and mechanical stiffness. In particular, a plaster and a mortar with 2% (by weight) of bamboo fibers of Phyllostachys Iridescens species has been analyzed. A mechanical characterization is carried out evaluating flexural strength, compressive strength and fracture energy. The effectiveness of the reinforcement is shown through the comparison with the unreinforced materials.

The good mechanical performance of bamboo, coupled with its sustainability, has boosted the idea to use it as a structural material. In some areas of the world it is regularly used in constructions but there are still countries in which there is a lack of knowledge of the mechanical properties of the locally-grown bamboo, which limits the spread of this material. Bamboo is optimized to resist to flexural actions with its peculiar micro structure along the thickness in which the amount of fibers intensifies towards the outer layer and the inner part is composed mostly of parenchyma. The flexural strength depends on the amount of fibers, whereas the flexural ductility is correlated to the parenchyma content. This study focuses on the flexural strength and ductility of six different species of untreated bamboo grown in Italy. A four-point bending test was carried out on bamboo strips in two different loading configurations relating to its microstructure. Deformation data are acquired from two strain gauges in the upper and lower part of the bamboo beam. Difference in shape and size of Italian bamboo species compared to the ones traditionally used results in added complexity when performing the tests. Such difficulties and the found solutions are also described in this work. The main goal is to reveal the flexural behavior of Italian bamboo as a functionally graded material and to expand the knowledge of European bamboo species toward its use as a structural material not only as culm but also as laminated material.

A residential building designed by the architect Anna Zanetti and already built in Costa Rica using Guadua angustifolia and Dendrocalamus asper is redesigned, choosing the municipality of Bologna, in the north part of Italy, as the construction site and Moso (Phyllostachys edulis) cultivated in Italy, as structural material. The redesign is performed in the context of Italian standards. The paper demonstrates how it is possible to design a building using European bamboo, geometrically smaller in respect to the tropical one, in compliance with the Italian national standards NTC2018 with the aid of Bamboo International standards (ISO 22156). All the members are multi-culms and the connections are chosen without perforations.

Abstract: A non-isothermal phase field model that captures both displacive and diffusive phase transformations in a unified framework is presented. The model is developed in a formal thermodynamic setting, which provides guidance on admissible constitutive relationships and on the coupling of the numerous physical processes that are active. Phase changes are driven by temperature-dependent free-energy functions that become non-convex below a transition temperature. Higher-order spatial gradients are present in the model to account for phase boundary energy, and these terms necessitate the introduction of non-standard terms in the energy balance equation in order to satisfy the classical entropy inequality point-wise. To solve the resulting balance equations, a Galerkin finite element scheme is elaborated. To deal rigorously with the presence of high-order spatial derivatives associated with surface energies at phase boundaries in both the momentum and mass balance equations, some novel numerical approaches are used. Numerical examples are presented that consider boundary cooling of a domain at different rates, and these results demonstrate that the model can qualitatively reproduce the evolution of microstructural features that are observed in some alloys, especially steels. The proposed model opens a number of interesting possibilities for simulating and controlling microstructure pattern development under combinations of thermal and mechanical loading. [Copyright &y& Elsevier]