M. Rosário Veiga

Bio: M. Rosário Veiga is an academic researcher from Laboratório Nacional de Engenharia Civil. The author has contributed to research in topics: Cement & Mortar. The author has an hindex of 5, co-authored 11 publications receiving 247 citations.

Physico-mechanical and performance characterization of mortars incorporating fine glass waste aggregate

Abstract: The effective management of construction and demolition waste (CDW) is a major challenge for the construction sector. To address such needs, this research work focuses on a specific type of CDW – annealed plate glass – to be incorporated into cementitious renderings. Studies on glass waste are very recent, scarce, and usually limited to the alkali-silica reaction (ASR), but they tend to involve other types of glass. This work characterizes the physical–mechanical and performance of these modified mortars, something that has not yet been done. A main reason for this lack of knowledge is the serious concern that there is an ASR potential. However, a recent study [1] concluded that the approach set out in ASTM C 1260 (accelerated mortar bar test) [2] may be overly conservative for renderings because it significantly increases the cement content. That study concluded that the use of mortars containing waste glass is technically viable in terms of ASR-related durability as long as the cement type and content are controlled, as well as the size of the aggregates, which proved to be the most decisive parameter [1] . In our study, mortars with a cement-to-sand volumetric ratio of 1:4 were produced with a fraction of the sand replaced by fine glass aggregates (0%, 20%, 50% and 100% by volume), while the aggregate’s size distribution in the replacement remained constant so that the material itself was the single factor under analysis. The study reveals significantly improved results, especially at the level of the mechanical performance and physical compatibility with the substrate, when these mortars are compared with similar ones containing other waste types and a conventional mortar (with only natural sand as aggregate).

Methodologies for characterisation and repair of mortars of ancient buildings

Abstract: There is a clear need to de velop and systematise a methodology to approach interventions on ancient renders. In fact inadequate interventions, with systematic resource to modern solutions, originated in Portugal a situation characterised by the disappearing of original lime renderings and finishings and caused several anomalies due to functional incompatibility between pre-existing elements and new materials. The research project Oldrenders, accomplished by researchers from LNEC in collaboration with the construction enterprise STAP - Reparacao, Consolidacao e Modificacao de Estruturas, SA., and partially financed by Agencia de Inovacao , has as main objectives the definition of such a methodology and the preparation of criteria to support the selection of substitutive compatible mortars. This paper synthesises the aims and conclusions of the Project. 1. OBJECTIVES OF THE RESEARCH Interventions on ancient buildings included for too long the systematic remotion of the original renders, plasters and finishings and its substitution by render s and plasters based on Portland cement, painted with products based, first in oil paints and then in acrylic and vinylic resins. In the meantime, the theory of conservation has more and more pointed out the historic and aesthetic importance of preservati on of material evidences and their fundamental part in the definition of formal and material authenticity of historic artifacts.

RILEM TC 277-LHS report: a review on the mechanisms of setting and hardening of lime-based binding systems

Abstract: The main objective of RILEM TC LHS-277 “Specifications for testing and evaluation of lime-based repair materials for historic Structures” is the revision, adaption and, when necessary proposal, of the test methods to accurately study lime-based binding systems and mixtures, such as mortars and grouts. The empiric use of the lime-based composites and the predominant employ of cement in the field of Civil Engineering have led to the widespread application of test methods developed for cement-based composites to test the former. However, the clear differences in composition and performance between modern cement binders and lime-based materials would advise to explore specific test methods for the latter. To undertake this task the previous knowledge on the mechanisms of setting and hardening of these binders must be revised, arranged and synthesized. Processes such as drying, carbonation, hydration and pozzolanic reaction may occur during the setting and hardening of lime-based mortars and competition between them cannot be underestimated. With the aim of underpinning the revision and proposal of test methods for lime-based systems, this review paper reports a comprehensive study of the mechanisms of setting and hardening of these binders, considering the variability of the composition, which includes pure air lime as well as lime with hydraulic properties, lime-cement and lime-pozzolan systems.

Modelling of lime mortar carbonation

Abstract: The carbonation process in lime mortar is influenced by the diffusion of carbon dioxide into the mortar pore system, by the kinetics of the lime carbonation reaction, and by the drying and wetting process in the mortar. All these phenomena depend on the presence of water in the mortar. Water is present in liquid form as well as vapour. Physical models and their mathematical basis are given for the factors influencing carbonation. The mathematical description of the carbonation process in lime mortar completes the information necessary to model the simulation of carbonation in conjunction with the drying process. Simulations at different carbon dioxide concentrations showed a good correlation between experiment and mathematical prediction.ResumeOn donne un aperçu général des différents facteurs qui influencent la carbonatation du mortier à la chaux. On démontre que le contenu d'eau dans le matériau influence la carbonatation aussi bien par un changement de la diffusivité à travers le matériau que par un changement de la réaction entre le gaz carbonique et la chaux. Un modèle mathématique a été développé qui permet la simulation du processus de la carbonatation en tenant compte de l'évolution de séchage du matériau dans son environnement. Des simulations avec des concentrations de gaz carbonique différentes montrent une bonne corrélation entre les expériences et les prédictions mathématiques.

Lime-Based Mortars: Viability for Use as Substitution Renders in Historical Buildings

Abstract: External renders based on air lime are used in historical buildings as decorative and protective coats. They act as sacrificial layers, particularly exposed to climatic actions and mechanical and environmental impact. They generally present good cohesion and adhesion to the background, although often suffer some degradation as detachments, superficial cracks, or 'lacunae'. Render solutions specified today for old buildings repair are frequently incompatible with pre-existent materials and inappropriate for the specific situation, thus producing new pathology. The choice of adequate materials, formulation, and curing conditions of substitution mortars become crucial for the success of the conservation action. These mortars must meet functional and aesthetic requirements, to fulfill the principles of compatibility, maintaining buildings' integrity and durability. An analysis is presented of ranges of results for different lime-based mortars for old buildings external renders, obtained in several studies car...