Properties of Portland Cement Mortar with Substitutions of Natural and Expanded Perlite

The present research deals with the feasibility of using high-temperature pozzolans such as Natural Perlite (NP) and Expanded Perlite (EP), different dosagues of additions were made to mortars in order to perform their mechanical properties. Mortars were subjected to destructive tests in hardened state: compression, tension, flexion and adhesion strength; as well as non-destructive tests in hardened state: ultrasonic pulse velocity (UPV), electrical resistivity (ER), density (ρ) and total porosity (PT); in addition to attack by sodium sulfate at 90 days. The percentages of the substitutions were 5%, 10%, 15%, 20% and 30% by weight of Portland cement mass (PC) relative to a control mortar (cement-sand-water). With the partial replacement of the cement and according to the tests carried out, it can be observed that the problem of durability and CO2 emissions is significantly reduced and, consequently, an energy saving and a lower environmental impact are promoted

Contribución del aplanado de morteros de cal para restauración sobre muretes de mampostería

Los morteros con base cal, han sido materiales descritos en los tratados antiguos de arquitectura, permitidos en muchos documentos que rigen los trabajos de restauración de bienes inmuebles patrimoniales y actualmente son los materiales más empleados en la restauración y conservación del patrimonio de mampostería natural en muchos sitios del mundo. La cal puede ser normalizada o bien puede ser apagada en sitio como describe Vitrubio en sus Libros de Arquitectura; los áridos pueden ser ígneos, metamórficos o sedimentarios; para modificar las propiedades físicas y mecánicas básicas de los morteros de cal suelen agregarse aditivos orgánicos e inorgánicos. La restauración y conservación de los edificios de mampostería coloniales es un reto en México. Tenemos 9 ciudades coloniales cuyos centros históricos están en el listado de Patrimonio de la Humanidad de la Unesco. Todas edificadas con mamposterías de rocas naturales y aplanadas con morteros de cal y aditivos orgánicos. Inicialmente se recubrían las rocas que carecían de labrado, cánones dictados por la arquitectura en boga. Con la modernización y masificación del transporte, los residuos vertidos a la atmósfera han deteriorado la calidad del aire ambiental resultando en pátinas, costras negras, daño antropogénico en superficies expuestas, devitrificación de la matriz de las rocas. Del uso sugerido de emplear morteros como protección en los monumentos arquitectónicos coloniales, método relativamente simple y económico, se ha revisado también su efecto sobre la resistencia mecánica. Este trabajo hace una comparación entre pilas de mampostería de arcilla recocida adheridas con mortero de cal adicionado con fibras desecadas y pulverizadas de nopal cactus opuntia y pilas con las mismas características, pero recubiertas en ambas caras con el mortero mencionado.Tópico 4.- Morteros de cal, materiales cálcicos y cementíceos. Evaluación de propiedades y composición. Mampostería de ladrillos. Caracterización. Evaluación de patologías y Refuerzo

Use of Audiovisual Methods and Documentary Film for the Preservation and Reappraisal of the Vernacular Architectural Heritage of the State of Michoacan, Mexico

The State of Michoacan has a wide and rich architectural heritage which is represented by different vernacular typologies which employ different materials and techniques according to the local resources. However, this wide knowledge and cultural heritage are disappearing, with several monuments and buildings being abandoned due to new dynamics and social changes. The traditional techniques have been substituted for modern and industrial construction systems since they are associated with obsolete ways of life. Through international cooperation for development and research projects, many activities were carried out to analyze the durability of local materials and vernacular constructions of the state. The main ones included the architectural survey and inspection of these buildings, photographic and drone surveys, characterization in the laboratory and oral interviews with local users. During the field work, these interviews with the local population, the creation of multimedia content and the use of audiovisual methods had crucial importance in the documentation of this local knowledge and culture, being great methods for scientific communication and dissemination. The main product is the documentary Xirangua, which means ‘roots’ in the Purépecha language, the main indigenous ethnicity in the state. This documentary explores the traditional architecture and construction of Michoacan, showing the reality within the loss of this vernacular heritage and portraying the importance of its conservation through the perspective of the local population, users and artisans. The use of these audiovisual techniques has demonstrated to be a suitable option to promote and preserve cultural heritage and educate, include the local actors in the process, and make the general public aware of the current issues, with this being one of the first works which explores this approach

<i>Mycobacterium tuberculosis</i> Cell Wall Antigens Induce the Formation of Immune Complexes and the Development of Vasculitis in an Experimental Murine Model

Tuberculosis (TB) of the central nervous system (CNS) presents high mortality due to brain damage and inflammation events. The formation and deposition of immune complexes (ICs) in the brain microvasculature during Mycobacterium tuberculosis (Mtb) infection are crucial for its pathobiology. The relevance of ICs to Mtb antigens in the pathogenesis of CNS-TB has been poorly explored. Here, we aimed to establish a murine experimental model of ICs-mediated brain vasculitis induced by cell wall antigens of Mtb. We administered a cell wall extract of the prototype pathogenic Mtb strain H37Rv to male BALB/c mice by subcutaneous and intravenous routes. Serum concentration and deposition of ICs onto blood vessels were determined by polyethylene glycol precipitation, ELISA, and immunofluorescence. Histopathological changes in the brain, lung, spleen, liver, and kidney were evaluated by hematoxylin and eosin staining. Our results evidenced that vasculitis developed in the studied tissues. High serum levels of ICs and vascular deposition were evident in the brain, lung, and kidneys early after the last cell wall antigen administration. Cell wall Mtb antigens induce strong type III hypersensitivity reactions and the development of systemic vasculitis with brain vascular changes and meningitis, supporting a role for ICs in the pathogenesis of TB