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• Single and dual nanoparticle-based treatments are used for preserving materials. • Hardness and erosion properties were improved using these nanoparticles (NPs). • A new C-S-H cementing gel is formed when Ca(OH)2/SiO2 NPs are combined. • The NPs did not significantly alter water vapour permeability. • ΔE was suitable in all cases (0.40–3.79), except for Ca-NPS (5.10). This paper studies the effectiveness of four consolidation treatments based on nanoparticles suspensions: calcium hydroxide (Ca-NP), magnesium hydroxide (Mg-NP), a treatment combining calcium hydroxide and magnesium hydroxide (Ca/Mg-NP), and a treatment consisting of calcium hydroxide and silicon dioxide (Ca/Si-NP) that were both applied separately. The suspensions were sprayed on gypsum plasters and lime renders which are common substrates in historical constructions and show a high degree of similarity with the treatments. The consolidation efficiency was evaluated using non-destructive techniques, such as peeling test, Shore-D hardness, water flow using Karsten tube and water vapour permeability tests. In addition, TEM images and XRD tests demonstrated the formation of a new C-S-H cementing phase when Ca/Si-NPs were combined due to a reaction between Ca(OH) 2 with SiO 2. Colour tests (CIE-L*a*b*) showed the consolidants did not produce major colour alterations, although the Ca-NP treatment caused a slight lightness increase. The strengthening effect was greater in lime mortars and water flow was moderately reduced in all treatments, except in mortars coated with Ca/Mg-NP. Finally, the chemical nature of the treatments is similar to the substrates, and they did not significantly alter the water vapour permeability of the studied materials. [ABSTRACT FROM AUTHOR]

Global concerns have been excited by burgeoning electromagnetic pollution and climate change. Paying attention to building materials is one of the best ways to refine electromagnetic pollution and save energy. Herein, a practical nanocomposite has been introduced that not only absorbs microwaves, but also plays a significant role in energy‐saving. Interestingly, the approach related to the selection of a simple experimental procedure, cost‐effective substrates, and building matrix develops the practical applications of the eventual product. Initially, graphite‐like carbon nitride (g‐C3N4) nanosheets are tailored using a conventional sintering route, and then the prepared nanosheets are ornamented by zinc sulfide (ZnS) nanoparticles through a facile hydrothermal scenario. Remarkably, the microwave and optical features of the tailored ZnS/g‐C3N4 nanocomposite are modulated by regulating the mass fraction of ZnS into 2D structures. Interestingly, a novel defecting agent is used to boost the dielectric characteristics of g‐C3N4 through an innovative complementary hydrothermal and combustion scenario. Eventually, the architected structures are blended with gypsum plaster to evaluate energy‐saving and microwave‐absorbing performance. The nanocomposites fabricated by ZnS/defected g‐C3N4/gypsum plaster as building materials have significant microwave‐absorbing and infrared reflection capacity. The presented research opens a new vista for simultaneous development of advanced functional materials for energy‐saving and microwave absorption. [ABSTRACT FROM AUTHOR]

Biomaterials are materials that are used to manufacture devices that interact with biological systems. According to their chemical composition, they can be classified as biometals, biopolymers, bioceramics, biocomposites and semiconductors. Thus, in the present work, the application of bioceramics, enhanced with effective microorganisms, to construction materials (cement mortars and gypsum plasters) was studied in order to see the benefits that its incorporation contributes to construction materials. This first work constitutes the first phase of an experimental campaign in which the influence of bioceramics on the physical and mechanical properties (flexural and compressive strength) of the studied materials was analyzed. Furthermore, scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) techniques were used. According to the results, a slight improvement in the mechanical properties of the new composites was observed. Besides, a more compact matrix was observed when bioceramics were used as an aggregate to the mixtures. [ABSTRACT FROM AUTHOR]

The article presents the influence of the type of substrate and its treatment on the pull-off strength of gypsum plaster. Most of the papers describe the effect of recommended surface treatment. The main target of this study is to show that different approaches of preparing primer have an impact on the properties of gypsum plaster. For the purpose of the article, three different types of concrete substrate were analyzed: aerated, light-weight and ordinary. Samples of the surfaces were treated by applying primer or diluted primer. To compare strength results, one of the substrate surfaces was prepared without the primer. Pull-off strength tests were performed for all the samples. As a result of this study, it has been proved that the optimal substrate surface for gypsum plaster is light-weight concrete. Moreover, it was found that applying primer negatively affects the pull-off strength of gypsum plaster. Using the primer, the gypsum plaster dry-off process is disturbed. This new discovery can be helpful to understand the primer impact on the pull-off strength of the gypsum plaster, and it shows that the primer composition needs to be analyzed and there should be taken actions to improve it properties. [ABSTRACT FROM AUTHOR]

Biomaterials are materials that are used to manufacture devices that interact with biological systems. According to their chemical composition, they can be classified as biometals, biopolymers, bioceramics, biocomposites and semiconductors. Thus, in the present work, the application of bioceramics, enhanced with effective microorganisms, to construction materials (cement mortars and gypsum plasters) was studied in order to see the benefits that its incorporation contributes to construction materials. This first work constitutes the first phase of an experimental campaign in which the influence of bioceramics on the physical and mechanical properties (flexural and compressive strength) of the studied materials was analyzed. Furthermore, scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) techniques were used. According to the results, a slight improvement in the mechanical properties of the new composites was observed. Besides, a more compact matrix was observed when bioceramics were used as an aggregate to the mixtures.

Building retrofitting plays a key-role in energy saving and a growing interest is focused on insulating materials that allow a reduction in heat loss from envelopes with low thickness, by a process of reducing heating and cooling demand. In this context, a complete characterization of the physical properties of Moroccan natural gypsum materials was carried out. Basic information on the mineralogical, microstructure, thermal, mechanical, and acoustic characteristics of the rocks sampled from two Moroccan regions is provided. It was found that mineralogy, porosity, and water content are the main factors governing the development of the structure and the strength of the samples. The measured values of the porosity were 8.94%, the water content varied between 2.5–3.0% for the two studied typologies, coming from Agadir and Safi, respectively. Gypsum powder was used for fabricating samples, which were investigated in terms of thermal and acoustic performance. Thermal properties were measured by means of a hot disk apparatus and values of conductivity of 0.18 W/mK and 0.13 W/mK were obtained for Agadir and Safi Gypsum, respectively. The acoustic performance was evaluated in terms of absorption coefficient and sound insulation, measured by means of a Kundt's Tube (ISO 10534-2). The absorption coefficients were slightly higher than the ones of conventional plasters with similar thickness. A good sound insulation performance was confirmed, especially for Safi Gypsum, with a transmission loss-value up to about 50 dB at high frequency. [ABSTRACT FROM AUTHOR]

The continuous and rapid evolution in the field of computing, and in particular in the field of storage devices, has led to the obsolescence of optical discs in favour of mass storage devices. In that sense, a large number of CDs and DVDs become obsolete each day in the world. In trying to create a recovery solution for those pieces, research in which polycarbonate (PC) waste from recycled discs have been used to develop new gypsum coating materials and products has been conducted. In a previous study, the physical and mechanical properties of new gypsum plasters, with PC waste as aggregate, were studied. Following that study, this article aims at creating new gypsum plaster false ceiling plates, using CD and DVD residues in different scenarios: as crushed aggregate in the gypsum matrix, as full reinforcement pieces of the plates and as a combination of both. The mechanical behaviour and the thermal conductivity of the new pieces have been analysed in this paper. The results showed an important improvement in the mechanical and thermal properties of the plates when the PC waste was used in many scenarios.

Large amounts of wood waste are generated each year in the world. In an attempt to identify a good recovery option for those residues, wood waste from construction and demolition works were used as raw materials in gypsum plasters. However, wood is a biodegradable material which implies that the products or materials that contain it are susceptible to suffering an important deterioration, due to exposure in certain environments. For that reason, the aim of this work was to simulate the effects that, in the long term, the atmospheric exposure of wood waste−gypsum composites would have. To do that, the plasters were subjected to 5, 10, and 15 wetting−drying cycles in a climatic chamber. In this study, the density, flexural and compressive strength, and ultrasonic velocity of these composites were determined by the influence of the aging process on their mechanical properties. Furthermore, in order to detect changes on their internal structure, scanning electron microscopy tests (SEM) were used. The results showed that they were suitable to be used as indoor coverings of buildings. However, a treatment to reduce the moisture absorption of the wood waste must be studied if mixtures with high percentages of wood shavings (WS20) are used in wet rooms.

Building retrofitting plays a key-role in energy saving and a growing interest is focused on insulating materials that allow a reduction in heat loss from envelopes with low thickness, by a process of reducing heating and cooling demand. In this context, a complete characterization of the physical properties of Moroccan natural gypsum materials was carried out. Basic information on the mineralogical, microstructure, thermal, mechanical, and acoustic characteristics of the rocks sampled from two Moroccan regions is provided. It was found that mineralogy, porosity, and water content are the main factors governing the development of the structure and the strength of the samples. The measured values of the porosity were 8.94%, the water content varied between 2.5−3.0% for the two studied typologies, coming from Agadir and Safi, respectively. Gypsum powder was used for fabricating samples, which were investigated in terms of thermal and acoustic performance. Thermal properties were measured by means of a hot disk apparatus and values of conductivity of 0.18 W/mK and 0.13 W/mK were obtained for Agadir and Safi Gypsum, respectively. The acoustic performance was evaluated in terms of absorption coefficient and sound insulation, measured by means of a Kundt’s Tube (ISO 10534-2). The absorption coefficients were slightly higher than the ones of conventional plasters with similar thickness. A good sound insulation performance was confirmed, especially for Safi Gypsum, with a transmission loss-value up to about 50 dB at high frequency.

This paper presents the effective diffusion and convective coefficients obtained for construction gypsum, perlite, and machine plaster pellets by using a dynamic single pellet moment technique at various temperature, and at different pressure drops. The experimental studies were performed by isobaric and non-isobaric conditions across between the upper and lower surfaces of the pellets. The experimental moment values obtained from the experiments carried out were used to calculate desired coefficients such as the effective diffusivity, tortuosity factor, D parameter, and Darcy coefficient. The experimental results for CO 2 diffusion in the pellets with porous at isobaric conditions showed that the effective diffusivity values for all gypsum plasters increase with increasing both pellet porosity and the temperature. It was observed that the tortuosity factor depends on macro porosity of the pellets used. The results indicated that the diffusion mechanism for all gypsum plasters is the transient regime diffusion. The effective diffusivity values decreased with increasing the pressure drop. In the range of pressure drop studied, both diffusive (at low pressure drops) and viscous (at high pressure drops) flows for CO 2 diffusion in construction gypsum and perlite plasters were dominant. But, the diffusion flow type which is important for machine plaster was only the viscous flow at all pressure drops. Finally, the Darcy coefficients of the gypsum plaster pellets were calculated. It was observed that the results were in agreement with the literature results obtained for porous solids similar to porous gypsum plaster pellets used in this study. [ABSTRACT FROM AUTHOR]

The ongoing global climate change and the associated environmental degradation pose a threat to Europe and the rest of the world. Raw materials and energy are required to produce building materials, which are used for construction purposes. Resulting buildings and structures generate waste during construction, operation, and demolition, and they emit potentially harmful substances. Thus, the key to achieving climate goals is to support low-emission materials and technologies in the construction sector, significantly impacting the environment. In the European Union, building materials are not yet subject to mandatory sustainability assessment during the assessment and verification of constancy of performance (AVCP). Objective evaluation of construction materials' environmental impact requires it to be carried out based on production data on an industrial scale. This article presents the environmental impact of premixed gypsum-based plasters, commonly used in modern construction. Nine environmental indicators (global warming potential (GWP), depletion potential of the stratospheric ozone layer (ODP), acidification potential (AP), eutrophication potential (EP), formation potential of tropospheric ozone (POCP), abiotic depletion potential (ADP)-elements, ADP-fossil fuels, renewable primary energy resources (PERT), and nonrenewable primary energy resources (PERNT)) of premixed gypsum plasters based on natural and flue gas desulfurization (FGD) gypsum were estimated and discussed. Knowledge of the construction products' environmental impact is fundamental for creating reliable databases. AVCP of construction materials in the future will use the data collected during the voluntary environmental impact evaluation. [ABSTRACT FROM AUTHOR]

The continuous and rapid evolution in the field of computing, and in particular in the field of storage devices, has led to the obsolescence of optical discs in favour of mass storage devices. In that sense, a large number of CDs and DVDs become obsolete each day in the world. In trying to create a recovery solution for those pieces, research in which polycarbonate (PC) waste from recycled discs have been used to develop new gypsum coating materials and products has been conducted. In a previous study, the physical and mechanical properties of new gypsum plasters, with PC waste as aggregate, were studied. Following that study, this article aims at creating new gypsum plaster false ceiling plates, using CD and DVD residues in different scenarios: as crushed aggregate in the gypsum matrix, as full reinforcement pieces of the plates and as a combination of both. The mechanical behaviour and the thermal conductivity of the new pieces have been analysed in this paper. The results showed an important improvement in the mechanical and thermal properties of the plates when the PC waste was used in many scenarios. [ABSTRACT FROM AUTHOR]

Large amounts of wood waste are generated each year in the world. In an attempt to identify a good recovery option for those residues, wood waste from construction and demolition works were used as raw materials in gypsum plasters. However, wood is a biodegradable material which implies that the products or materials that contain it are susceptible to suffering an important deterioration, due to exposure in certain environments. For that reason, the aim of this work was to simulate the effects that, in the long term, the atmospheric exposure of wood waste–gypsum composites would have. To do that, the plasters were subjected to 5, 10, and 15 wetting–drying cycles in a climatic chamber. In this study, the density, flexural and compressive strength, and ultrasonic velocity of these composites were determined by the influence of the aging process on their mechanical properties. Furthermore, in order to detect changes on their internal structure, scanning electron microscopy tests (SEM) were used. The results showed that they were suitable to be used as indoor coverings of buildings. However, a treatment to reduce the moisture absorption of the wood waste must be studied if mixtures with high percentages of wood shavings (WS20) are used in wet rooms. [ABSTRACT FROM AUTHOR]