Architectural analysis of the Antezana Hospital: a 15th century noble house in the historic city of Alcalá de Henares (Madrid, Spain)

This paper presents a multidisciplinary study of the Antezana Hospital, a former mid-15th century noble house. The aim is to identify the appearance, the construction techniques and the materials of the original house before becoming a hospital, highlighting the historic value of the building The methodology combines four main steps. First, the main historical dates were established based upon historic archives, drawings and photographs. Second, a materials characterization was carried out, analysing several samples of bricks and their associated mortars from different chronology and location. Third, a morphological analysis of the different materials and constructive elements was accomplished. And finally, an architectural analysis of the building was performed, allowing an interpretation of the building chronology and relating historical information with materials and construction techniques. This multidisciplinary approach provided new pieces of information that allow identifying the original construction techniques, which was not described in detail in the literature. According to the results, a link could be established between the Hospital and other contemporary buildings. Some architectural elements were related to other 15th century noble houses located in Toledo, while the materials were found to be similar to those of the original 15th century College of the University of Alcalá, founded by Cardinal Cisneros

Architectural analysis of the Antezana Hospital: a 15th century noble house in the historic city of Alcalá de Henares (Madrid, Spain)

This paper presents a multidisciplinary study of the Antezana Hospital, a former mid-15th century noble house. The aim is to identify the appearance, the construction techniques and the materials of the original house before becoming a hospital, highlighting the historic value of the building The methodology combines four main steps. First, the main historical dates were established based upon historic archives, drawings and photographs. Second, a materials characterization was carried out, analysing several samples of bricks and their associated mortars from different chronology and location. Third, a morphological analysis of the different materials and constructive elements was accomplished. And finally, an architectural analysis of the building was performed, allowing an interpretation of the building chronology and relating historical information with materials and construction techniques. This multidisciplinary approach provided new pieces of information that allow identifying the original construction techniques, which was not described in detail in the literature. According to the results, a link could be established between the Hospital and other contemporary buildings. Some architectural elements were related to other 15th century noble houses located in Toledo, while the materials were found to be similar to those of the original 15th century College of the University of Alcalá, founded by Cardinal Cisneros

Assessment of lime-cement mortar microstructure and properties by P- and S- ultrasonic waves

Lime-cement mortars are used for repairing building walls, improving thermal and acoustic performance through the modification of their composition and, consequently, their microstructure and properties. In order to evaluate the applicability of ultrasonic (US) waves to better understand the relationships among composition-microstructure-properties, an experimental program using transmission P- and S- waves was carried out. The properties of ten mortars were assessed by US parameters as velocity, moduli and attenuation coefficient. Water to binder ratio, porosity and thermal conductivity showed good correlation to US modulus while S-wave attenuation was linked to sound absorption and the incorporation of fibres. Flexural strength correlated to P-wave attenuation, while a combination of S-wave attenuation and moduli was needed to adjust compressive strength. These correlations can be useful tools for predictive models development, composition optimization and US on-site evaluation.The authors wish to acknowledge the financial support for this Research, provided by the Grant for training of Lecturers (FPU-UAH 2013), funded by University of Alcalá. Some of the components were supplied by BASF Construction Chemicals España S.L., Omya Clariana S.L. and Readymix-Asland S.A

Acoustic Assessment of Multiscale Porous Lime-Cement Mortars

Noise pollution is an issue of high concern in urban environments and current standards and regulations trend to increase acoustic insulation requirements concerning airborne noise control. The design and development of novel building materials with enhanced acoustic performance is an efficient solution to mitigate this problem. Their application as renders and plasters can improve the acoustic conditions of existing and brand-new buildings. This paper reports the acoustic performance of eleven multiscale porous lime-cement mortars (MP-LCM) with two types of fibers (cellulose and polypropylene), gap-graded sand, and three lightweight aggregates (expanded clay, perlite, and vermiculite). Gap-graded sand was replaced by 25 and 50% of lightweight aggregates. A volume of 1.5% and 3% of cellulose fibers were added. The experimental study involved a physical characterization of properties related to mortar porous microstructure, such as apparent density, open porosity accessible to water, capillarity absorption, and water vapor permeability. Mechanical properties, such as Young?s modulus, compressibility modulus, and Poisson?s ratio were evaluated with ultrasonic pulse transmission tests. Acoustic properties, such as acoustic absorption coefficient and global index of airborne noise transmission, were measured using reduced-scale laboratory tests. The influence of mortar composition and the effects of mass, homogeneity, and stiffness on acoustic properties was assessed. Mortars with lower density, lower vapor permeability, larger open porosity, and higher Young?s and compressibility modulus showed an increase in sound insulation. The incorporation of lightweight aggregates increased sound insulation by up to 38% compared to the gap-graded sand reference mixture. Fibers slightly improved sound insulation, although a small fraction of cellulose fibers can quadruplicate noise absorption. The roughness of the exposed surface also affected sound transmission loss. A semi-quantitative multiscale model for acoustic performance, considering paste thickness, active void size, and connectivity of paste pores as key parameters, was proposed. It was observed that MP-LCM with enhanced sound insulation, slightly reduced sound absorption.Financial support for this research was provided by Comunidad de Madrid and the Universidad de Alcalá (Spain), as part of the project IndoorComfort (CM/JIN/2019-46) under the Research Program for the Promotion of Young Researcher

A multiscale model for pervious lime-cement mortar with perlite and cellulose fibers

A pervious lime-cement mortar (PLCM) with perlite (P) and cellulose fibers (FC) was studied for better understanding the relationships among mortar composition, microstructure and properties, especially thermal and acoustic performance. Mortar microstructure was studied by optical and scanning electron microscopy, water absorption and nitrogen adsorption/desorption tests. A multiscale model for PLCM with and without P and/or FC was proposed: a three-phase macrostructural model consisting on a gap-graded aggregate, a paste shell and a continuous void network; paste phase was described as a multiphase microstructure. Paste thickness and active void size were identified as PLCM macrostructural parameters. The use of P and FC widened the paste shell, reducing the active void size. While the effect of P depends on particle size rather than the proportion used, the effect of FC depended on fiber amount. The model could be useful for optimizing the design of PLCM and predicting thermal and acoustic performance.Financial support for this research was provided by the Grant for training of Lecturers (FPU-UAH 2013), funded by University of Alcalá. Some of the components were supplied by Omya Clariana S.L. and Cementos Portland Valderrivas S.A

La junta en los sistemas de elementos para fachada : función constructiva, compositiva y estructural

La Tesis presenta el estudio realizado sobre el comportamiento de un Nuevo Diseño de Junta Vertical para paneles de fachada. Comienza con un análisis funcional de las soluciones de junta existentes, determinando las deficiencias que presentan. Asimismo, se detallan las ventajas que ofrecen otras soluciones de juntas entre elementos constructivos superficiales destinados a otros usos diferentes al de cerramiento y el uso de nuevos materiales que se pueden aplicar en las juntas. Los resultados de este estudio preliminar acotan los problemas que se presentan en las jutnas y se utilizan para enunciar criterios de diseño de nuevas soluciones de junta para paneles de fachada. Se tienen en cuenta las funciones Constructiva, Compositiva y Estructural derivadas de su situación en la fachada del edificio. De acuerdo con estos criterios, se propone un Nuevo Diseño de Junta Vertical. Se trata de una junta colaborante, con sección en forma de V y la inclusión de una pieza de junta exterior. El Material de Junta se sitúa en dos planos oblicuos respecto a la fachada y responde a las acciones exteriores combinando esfuerzos normales y de corte, aumentando la capacidad mecánico co_ respecto a otras juntas colaborantes. Se estudia experimentalmente el comportamiento de esta nueva configuración aplicada a paneles de acero y hormigón, con el fin de determinar su capacidad mecánica frente a acciones exteriores y su compatibilidad con los paneles de fachada. Como materiales se junta se utilizan Resina Expoxi Tenaz y Mortero de Cemento Modificado con Látex. Posteriormente se analiza por Elementos Finitos la demanda que produce en las juntas el comportamiento de los paneles sometidos a acciones gravitatorios, de viento y sísmicas. El Nuevo Diseño de Junta con los materiales utilizados se comporta como un Mecanismo Pasivo de Amortiguamiento frente a acciones dinámicas exteriores. Por último, se evalúa el sistema, teniendo en cuenta con aspectos relacionados con la forma de la junta, los materiales utilizados, el procedimiento de ejecución, el comportamiento frente a acciones exteriores y su durabilidad

Long Term Permeability and Acid Resistance of SelfCompacting Concretes with Micro and Nano Mineral Additions

Self-Compacting Concrete (SCC) can incorporate different types of Supplementary cementitious materials (SCM), as filler and other active mineral additions, to increase the amount of paste without increasing the amount of cement. SCM modify the SCC hardened microstructure due to the filler effect, the seeding effect as nucleation points for hydration products and the pozzolanic effect in the case of reactive SCM, as mineral additions (MA). The pore network is also modified which produce changes in the permeability of SCC. It is generally considered that the increase of fine particles improves SCC durability due to the larger compactness of the hardened material. However, MA also modifies the hydration process and consequently the hardened microstructure that could, in some cases, reduce the chemical resistance. Accordingly, the durability of SCC can also be modified by the use of MA due to the combination of permeability and chemical resistance, which mainly depends on the paste phase of the composite. When subjected to chemical attacks, SCC with MA would also modify the microstructure and the permeability properties in the long term. In order to evaluate the effect of different mineral additions, as limestone filler, microsilica, nanosilica and metakaolin, on SCC long term performance and assess their impact on its durability, an experimental study was carried out. Air and water permeability was measured on 5 years old samples SCC with different MA. It was seen that SCC air permeability was similar independently of the MA type and amount used. The samples were then subjected to acetic and sulfuric acid attacks. It was observed that the chemical resistance against acids depended on both permeability, the type of acid and the MA. The particle size and reactivity of the MA also contributed to the chemical resistance and therefore, to SCC durability

Extrusion and structural build-up of 3D printing cement pastes with fly ash, nanoclays and VMAs

3D printing technology (3DP) has provided new design and structural opportunities for cement-based systems (CBS) in architectural construction. However, there are still some issues related to extrudability and buildability of CBS, which can be overcome by using components for CBS rheology control. In this study, three types of nanoclays, a bentonite (BEN), a sepiolite (SEP) and an attapulgite (ATT), and two viscosity modifying admixtures (VMAs), a poly-acrylamide (VMA1) and a methylcellulose ether (VMA2), were added to a reference cement-fly ash 3D printing paste to evaluate their impact on CBS rheological properties and their implications in extrusion and buildability for 3DP. A polycarboxylate-ether based high range water-reducing admixture (HRWRA) was used to reach a target stiff consistency. Four laboratory tests were used to assess paste rheology, extrusion and structural build-up. Proper and deficient material extrusion limits were defined considering cohesion and initial yield stress. It was found that the combination of VMA2 and SEP increased cohesion, enhancing extrusion and avoiding water drainage and frictional behavior of pastes, producing properly extrudable paste. SEP by itself also improved structural build-up. Besides, samples with NC and VMAs required larger amounts of HRWRA, delaying cement setting and compressive strength gain.The authors acknowledge the financial support provided by the project Print3Dcement (PID2019-106525RB-I00) funded by the Spanish Ministry of Science and Innovation (MCIN), project CALTHED (grant number TED2021-132585B-100) funded by the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033) and the European Union “NextGenerationEU”/PRTR, the Grant for training of Lecturers (FPU-UAH 2019) and the trainee Research Personnel Mobility Grant (Movilidad PIF-UAH 2020) funded by University of Alcala. Also, the authors acknowledge the experimental laboratory help of Yohan Jacquet of Universit´e Bretagne-Sud. The authors also thank the materials’ supply of the company TOLSA GROUP S.A

Rheology characterization of 3D printing mortars with nanoclays and basalt fibers

3D printing has become one of the most innovative technologies for cement-based systems (CBS). However, recent studies have shown some issues related to printability and buildability (water drainage, plugs on extruder die, spreading of first layer, etc). To achieve a proper rheology control of CBS, it is essential to adapt the material fresh state properties (initial shear yield stress and structural build-up). In this study, a reference cement-based mortar with fly ash (25%), a 1:1.5 binder to sand ratio and a 0.38 water to binder ratio was used. A polycarboxilate ether-based superplasticizer was added until a consistency of around 1 kPa, measured with the cone-penetration test, was reached. Then, small amounts of several types of nanoclays (NC) in powder and slurry form (sepiolite, attapulgite and bentonite) and natural fibers were added to modify mortar rheological properties. The aim of the study was to characterize the rheological properties of 3D printing mortar samples with NC and basalt fibers (BF) to understand printability and buildability of this material. Cone-penetration test, flow table test and slump test were used to characterize 3D printing capacities. The cone-penetration test was performed in stirred and left at rest samples to assess shear yield stress before and after material deposition. Nanoclays showed a remarkable capacity to retain water and avoid drainage during extrusion but also to increase fresh state strength of material over time. Besides, they increased shear yield stress over time when left at rest. On the contrary, samples stirred over time did not show any increase of shear yield stress, especially samples with slurry nanoclays. Natural fibers also reduced drainage and enhance printability control regarding to reference mortar. BF also enhanced a performance on stirred sample but showed slightly changes on structural build-up at rest, mainly governed by NC effect.This study was partially funded by the Spanish Ministry of Science and Innovation, project Print3Dcement (grant number PID2019-106525RB-I00); by MCIN/AEI/10.13039/501100011033 and the European Union ‘‘NextGenerationEU”/PRTR, project CALTHED (grant number TED2021-132585B-100), and by the University of Alcalá, Grant for training of Lecturers (FPU-UAH 2019) and the trainee Research Personnel Mobility Grant (Movilidad PIF-UAH 2021). The authors acknowledge the experimental help of Sandipan Kaushik of Queen´s University Belfast (QUb). The authors also thank the materials’ supply of the company TOLSA GROUP S.A

Early age behaviour of Self Compacting Concrete with Polypropylene fibers and carbon nanofibers

An experimental study on the performance of a self compacting concrete (SCC) with fibers, during the cement hydration process and the evolution in to a rigid material, was carried out. The aim of this study was to investigate the improvement of the hardened performance due to the use of fibers and the early age cracking control ability of fibers at two different scales: on a nano-structural level with the addition of carbon nano-fibers (CNF) and on a micro-structural level with the addition of polypropylene micro-fibers. The inclusion of nanofibers increased the flexural strength of cement based pastes although some problems concerning early age cracking emerged. As any other concrete, SCC can exhibit problems during the very early ages after mixing, when cement hydration occurs, as shrinkage and early cracking. Although these problems arise during early ages, their effect can seriously compromise the long term performance and durability of the material. SCC samples with and without fibers were monitored through its hardening process using several experimental techniques and considering the effect of water evaporation due to wind exposition during the setting process. The effect of the fibers and different SCC components, as nanosilica, and a high range water reducing admixture (HRWRA), was analysed. Besides, the ability of the applied components to avoid the stress development during the early ages was also evaluated. The influence of the fibers and additional components on the early age shrinkage was assessed, identifying the relationship between shrinkage and early age cracking