Assessment of phase formation in lime-based mortars with added metakaolin, Portland cement and sepiolite, for grouting of historic masonry

Lime-based mortars containing pozzolanic additions of metakaolin, sepiolite and white Portland cement are studied in order to determine their performance as historic masonry conservation mortars. Hydration products on metakaolin – lime blended mortars include stable and metastable phases. The presence of such products has been studied by means of DTA and XRD analysis, concluding that the selection between them is mainly related with the water – lime ratio. Sepiolite addition to metakaolin – lime mortars has shown to inhibit C 4 AH 13 formation. Therefore, the in fluence of phase distribution on the mechanical resistance is considered. Finally, compounds production on blended lime–white Portland cement was compared to natural hydraulic lime ones, and as a result, no remarkable differences appeared, apart from traces of possible cement Portland addition to the latter, usually not mentioned in the nominal composition supplied by the manufacturers of lime binders

Influencia de las adiciones puzolánicas en los morteros de restauración de fábricas de interés histórico-artístico

En los morteros de restaruración de fábricas históricas, se pueden destacar dos requisitos fundamentales por encima del resto: una cierta hidraulicidad, que garantice el fraguado en tiempo y condiciones razonables, y una cierta afinidad con los conglomerantes calcáreos históricos, siempre que no haya riesgo de un colapso estructural inminente. Dado que los morteros hidráulicos, y los materiales que los componen, se estudian a menudo para otras prestaciones con requisitos opuestos a conservación y restauración del patrimonio, donde existen grandes lagunas en este campo, el objetivo de la tesis es favorecer el diseño de morteros de restauración mediante el empleo de cal con adiciones hidráulicas, puzolánicas y tixotrópicas, y estudio de su relación con las cales hidráulicas naturales (NHL). Para ello, primero se estudió la activación puzolánica de productos, en cuanto a: temperatura y tiempo de cocción, y su análisis por métodos químicos (Fratini), por métodos térmicos (TG/ATD) y por métodos mecánicos, con o sin aceleración del curado. Posteriormente se fabricaron varias series de morteros de cal aérea (control), de cal-MK, de cal-CPO, de NHL y de cal-MK-sepiolita, en los que se estudiaron sus propiedades físico-mecánicas (densidad, porosidad, absorción, resistencia, elasticidad), mediante balanza hidrostática, transmisión de ultrasonidos y prensado con medida de los desplazamientoss mediente LVDT, y se caracterizaron las fases de fraguado presentes, mediante el uso combinado de ATD/TG, DRX, MEB/DEX y espectrometría de masas. De donde, entre otras conclusiones, se establecieron las ventajas dudosas de los morteros de cal hidráulica natural frente a los de cal-cemento, los riesgos de las puzolanas altamente reactivas como el MK, las ventajas e inconvenientes de las arcillas plastificantes o tixotrópicas como la sepiolita, la inadecuación del clásico ensayo de Fratini para medir la puzolanicidad de materiales no cementícios, los problemas del curado en agua caliente de los morteros de cal y el interés del uso de puzolanas semi-reactivas, sobre lo que se proponene líneas de investigación futuras. Pero sobre todo, se comprobó la necesidad de una normalización rigurosa de los morteros de restauración. PALABRAS CLAVE: Morteros de restauración, morteros de cal aérea, morteros de cal hidráulica, puzolanas, metacaolín, sepiolita, fábricas históricas. ABSTRACT There are two main requirements which stand out over the rest on restoration mortars for historic masonries, as far as it won't be an imminent danger of structural collapse. Some hydraulicity, that guarantees a reasonable setting time in usual conditions, and affinity with historic lime binders. Hydraulic mortars and its constituent materials are usually tested for field. That's why the aim of this thesis is to contribute to designing restoration mortars made of lime mixed with hydraulic, pozzolanic and tixotropic additions. And to study its relation to natural hydraulic limes (NHL). Pozzolanic activation was first studied, concerning to burning time an temperature. Moreover, chemical analysis (Fratini), thermal analysis (TG/DTA) an mechanical tests of pozzolanic activity (with and without speeding up of curing time), were compared and checked. Afterwards, several mortars series were made of pure lime (control), MK-lime, OPC-lime, NHL, an MK-lime with sepiolite. Their physical-mechanical properties (density, porosity, absorption, strenghth, elasticity) were studied using hydrostatic balance, ultrasonic transmission, and loading with displacement registry by LVDT. Existing setting phases were characterized by means of combined use of TD/DTA, XRD, SEM/XED and mass spectrometry. Amongst other things, it was concluded that natural hydraulic lime mortars behaviour compared to cement-lime ones have doubtful advantages, and using high reactivity pozzolans like MK in restoration mortars, may be dangerous too. Advantages and disadvantages of using plasticizing or tixotropic clays, like sepiolite, were commented. Misappropriation of the classic Fratini test for pozzolanity measuring in non cementitious materials, was established. Difficulties of hot water curing for lime mortars, and semi-reactive pozzolans interest, were also analysed. And future investigation lines about all this things were proposed. Finally, this work brings out the need for an accurate normalization on restoration mortars. KEYWORDS: Restoration mortars, lime mortars, hydraulic mortars, pozzolans, metakaolin, sepiolite, historic masonries

Efficiency and effect of consolidation and water repelent treatments on stone materials. Case study: building restoration at Almudena Cemetery(Reumen)

En este trabajo se ha realizado un estudio experimental de la eficacia y efectos de diferentes productos consolidantes con base silicato de etilo o siloxanos. Se han aplicado sobre un material de naturaleza caliza y sobre ladrillos cerámicos pertenecientes a la fachada de edificios del Cementerio de la Almudena de Madrid en los que se realizaron trabajos de restauración. El objetivo es determinar el producto idóneo a utilizar para cada material. La selección del tratamiento de conservación se ha realizado en base al análisis de los resultados de los ensayos en laboratorio y atiende a su eficacia, idoneidad y compatibilidad con los materiales existentes. Estudiando la profundidad de penetración, la modificación de interfases, la posible alteración estética y la penetrabilidad de agua

Efficiency and effect of consolidation and water repelent treatments on stone materials. Case study: building restoration at Almudena Cemetery(Reumen)

En este trabajo se ha realizado un estudio experimental de la eficacia y efectos de diferentes productos consolidantes con base silicato de etilo o siloxanos. Se han aplicado sobre un material de naturaleza caliza y sobre ladrillos cerámicos pertenecientes a la fachada de edificios del Cementerio de la Almudena de Madrid en los que se realizaron trabajos de restauración. El objetivo es determinar el producto idóneo a utilizar para cada material. La selección del tratamiento de conservación se ha realizado en base al análisis de los resultados de los ensayos en laboratorio y atiende a su eficacia, idoneidad y compatibilidad con los materiales existentes. Estudiando la profundidad de penetración, la modificación de interfases, la posible alteración estética y la penetrabilidad de agua

Almallutx: A renovation proposal in a vernacular architecture example in sierra de Tramuntana (Mallorca)

The importance of the Built Vernacular Heritage is unquestionable as well as its uniqueness, due to the different techniques and materials used to adapt it to the site conditions. Because of its historical, social and cultural conditions, it is about protected goods whose conservation is a need understood by society and its institutions. This Thesis focuses on a renovation proposal in a vernacucular architectural example of a traditional Mallorcan architecture, studying a house located in the Sierra de Tramuntana, next to the Gorg Blau reservoir and known as the Finca de Almallutx. Initially, the traditional architecture of the area is analyzed to understand how it originally was and to identify the changes supported. This study is completed with the characterization of the current materials and systems. Taking into account all the above information, a renovation project is drawn up combining different needs: respect for traditional architecture, current technical solutions to the endemic problems of their original systems, the necessary adaptation to their current use and respect for the natural environment that surrounds it, which was awarded as World Heritage Site

Rheological and thermal properties of aerated sprayed mortar

This paper studies the rheological properties in aerated cement pastes in order to develop an aerated sprayed mortar with low thermal conductivity. For this purpose, different mixtures of cement with additions of metakaolin (MK) and sepiolite (SP) were tested. In addition, influence of yield stress on build-up thickness, as well as expansion speed and pore network were studied using cement pastes aerated with aluminum powder. At the same time, the volume increase during expansion, water retention and yield stress of the fresh foamed cement pastes were studied to characterize the fresh mortar. Results obtained show that the incorporation of siliceous fly ashes (SFA) in ordinary Portland cement together with additions of MK or/and SP provided the largest expansion speed increase and the lowest density of the aerated mortar. Pastes with greater yield stress show higher thermal conductivity but are better to be pneumatically gunited due to its bigger build up thickness. The most suitable paste from all them was selected, sprayed and aerated over ceramic bricks, checking the results on site. Results obtained by means of these tests confirm that is possible to spray an aerated mortar over vertical surfaces. In addition, this mortar has acceptable thermal insulation properties to be used in chambers of building façades and for external wall thermal insulation systems (EWIS).Sin financiación3.485 JCR (2017) Q1, 10/62 Construction & Building Technology, 11/128 Engineering, Civil; Q2, 72/285 Materials Science, MultidisciplinaryUE

Characterization of historic mortars: techniques used to establish a construction chronology. Case study: “Aragoneses’ Mill” as it belongs to popular architectural heritage

Restoration actions in building construction require complete preliminary studies. It is essential to perform tests for the characterization and identification of materials. In this work, mortars and bricks characterization as a method of dating constructive techniques have been used. A case study for the “House of Aragoneses”, an ancient watermill sited in Monachil, Granada, is presented. According to the building historical studies, there was an oil mill on that place that worked due to the Huenes River waterflow from the 15th to the 16th centuries. It may have disappeared because of the ravages of the Monachil Moorish properties in the riots prior to 1570. But from the documentary information existing in the archives, the construction works from XV to XVI century are not clear. The building underwent changes throughout history but there is not any documentation related to these interventions. By means of different tests and characterization techniques, dating and identification of existing masonry works at the “House of Aragoneses” has been accomplished

Characterization of historic mortars: techniques used to establish a construction chronology. Case study: “Aragoneses’ Mill” as it belongs to popular architectural heritage

Restoration actions in building construction require complete preliminary studies. It is essential to perform tests for the characterization and identification of materials. In this work, mortars and bricks characterization as a method of dating constructive techniques have been used. A case study for the “House of Aragoneses”, an ancient watermill sited in Monachil, Granada, is presented. According to the building historical studies, there was an oil mill on that place that worked due to the Huenes River waterflow from the 15th to the 16th centuries. It may have disappeared because of the ravages of the Monachil Moorish properties in the riots prior to 1570. But from the documentary information existing in the archives, the construction works from XV to XVI century are not clear. The building underwent changes throughout history but there is not any documentation related to these interventions. By means of different tests and characterization techniques, dating and identification of existing masonry works at the “House of Aragoneses” has been accomplished