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The application of curved Insulating Glass Units (IGUs) in facades has emerged as a novel solution to meet aesthetic and energy performance objectives. Due to improved stiffness, curved IGUs cannot equalise internal and atmospheric pressure changes by pillowing, as flat IGUs do. Thus, the climatic loads in curved IGUs may be several times higher than those in flat units. This paper deals with experiments and numerical simulations of cylindrically curved IGUs. It presents the results of an experimental campaign designed to collect data that validate the numerical model of a curved IGU developed within this study. The model is sequentially used to analyse a case study that compares the resulting internal pressure, displacement, and stress in glass in a flat and curved IGU subjected to the characteristic climatic actions given by DIN18008-1. [ABSTRACT FROM AUTHOR]

Alkali-activated materials (AAMs) are a group of environmentally friendly binders considered alternatives to conventional cementitious binders. They utilise industrial wastes such as slag and fly ash to reduce cement production and related CO2 emissions. Despite the strong interest of researchers, the application of alkali-activated concrete (AAC) in constructions is still very limited. Given the difference in the process of producing the AAC and ordinary Portland cement concrete (OPCC), some of the testing methods need to be adjusted to a new type of binder. The increased sensitivity of AAM to high temperatures leads to discussions on the results achieved in the gas permeability tests that require the samples to be dried first. In this paper, the influence of drying temperature applied to the samples on the gas permeability will be presented. The binders' precursors are blends of fly ash (FA) and ground granulated blast furnace slag (GGBFS) in slag proportions of 5%, 20%, and 35%, expressed by the mass of FA. Materials are denoted AAC5, AAC20, and AAC35, respectively. Measurements of the gas permeability of concretes were conducted by the RILEM–CEMBUREAU method, with lab adaptation for gas flow measurements. The comparison of results obtained shows the increase in gas permeability values with the temperature. However, the corresponding effect of temperature on permeability is driven by, on the one hand, the binder composition, and on the other hand, the aggregate's nature. [ABSTRACT FROM AUTHOR]

Diatomites are mineral resources formed from diatoms. They are widely used in sorption processes, medicine, cosmetology, and in protecting animals from parasites. Attempts are being made to incorporate them into concretes and construction binders to improve various performance properties. This paper presents the results of analyses (particle size analysis, XRD, and SEM) of a fine fraction of non-calcined and calcined diatomite as an additive to geopolymers made from fly ash from lignite combustion. The fly ash was also analyzed in the same way. Diatomite was introduced in its calcined and non-calcined form at 10%, 15%, and 30% by weight, replacing parts of the filler sand. The geopolymer mixtures were activated with 10 and 14 M aqueous sodium hydroxide solution with sodium water glass. As a result, it was found that it was possible to obtain geopolymers with diatomite additives with a compressive strength of about 34 MPa. In addition, after the strength tests, the microstructure of the obtained geopolymers was analyzed by scanning electron microscopy. [ABSTRACT FROM AUTHOR]

The significant reduction in CO2 emissions arising from the cementitious composites industry is one of the highest priorities for the construction sector's movement towards climate neutrality and sustainable development. One of the approaches to cope with this issue is to partially substitute cement with supplementary cementitious materials. Recently, various oil refinery wastes (ORW) have attracted researchers' attention in terms of being investigated for such an application. As such, the present paper shows the preliminary results of investigations conducted on cement pastes with the addition of a spent fluid catalytic cracking catalyst derived from a Polish oil refinery company. It is worth mentioning that the incorporation of ORW in cementitious composites might enable the production of more environmentally friendly construction materials without sacrificing quality, whilst, simultaneously providing an opportunity for recycling petrochemical wastes. [ABSTRACT FROM AUTHOR]

Geopolymers are new environmentally friendly cementitious materials that may offer an alternative to Ordinary Portland Cement. Not only do they have excellent mechanical properties, but they also have high temperature resistance. This research focuses on the high temperature exposure effect on geopolymer mortars. Two types of geopolymer mortars were prepared and exposed to different temperatures (20, 200, 400, 800 °C). The main goal of this work is to assess the changes in the mechanical and physical properties of geopolymer mortars after being exposed to a high temperature. Two types of mixtures were tested: one containing 100% fly ash (M0-K) and the other one containing 50% fly ash and ground Granulated blast furnace slag (M50-K). The paper presents an evaluation of compressive and tensile strength, density, porosity, and ultrasonic pulse velocity for both M50-K and M0-K after exposure to high temperatures. [ABSTRACT FROM AUTHOR]

Geopolymers are new environmentally friendly cementitious materials that may offer an alternative to Ordinary Portland Cement. Not only do they have excellent mechanical properties, but they also have high temperature resistance. This research focuses on the high temperature exposure effect on geopolymer mortars. Two types of geopolymer mortars were prepared and exposed to different temperatures (20, 200, 400, 800 °C). The main goal of this work is to assess the changes in the mechanical and physical properties of geopolymer mortars after being exposed to a high temperature. Two types of mixtures were tested: one containing 100% fly ash (M0-K) and the other one containing 50% fly ash and ground Granulated blast furnace slag (M50-K). The paper presents an evaluation of compressive and tensile strength, density, porosity, and ultrasonic pulse velocity for both M50-K and M0-K after exposure to high temperatures. [ABSTRACT FROM AUTHOR]

This publication presents the results of a study of the effect of partial replacement of cement with waste and natural materials: ground blast furnace slag, fly ash and lime meal on the strength properties of mortars compared to a reference mortar without these additives. In subsequent tests, these materials were gradually replaced with up to 10% CEM I cement. Their effects on consistency and compressive and flexural tensile strengths after 28 days of maturation were investigated. The tests were carried out on blocks measuring 40 mm × 40 mm × 160 mm according to the standard. In the range of tests analysed, the results obtained make it feasible to consider the possibility of partially replacing cement with silica fly ash and ground granulated blast furnace slag in cement mortars. [ABSTRACT FROM AUTHOR]

The article discusses the possibility of improving the properties of concrete made with composite ash-containing cement (CC) by introducing complex chemical additives. The pozzolanic activity of CC and its degree of hydration increases with the increasing dispersion of cement resulting from the introduction of a complex additive in the form of a polyfunctional modifier (PFM) during grinding, including a grinding intensifier-propylene glycol and a superplasticizer. The analysis of mathematical models of water demand and strength of concrete made with the PFM additive showed that a significant reduction in water demand and an increase in the strength of concrete based on the ash-containing CC is possible with the introduction of the PFM additive. For concrete based on CC with the addition of PFM, it has been demonstrated that it is possible to design concrete mixes on the basis of the obtained models. Relevant examples are provided. [ABSTRACT FROM AUTHOR]

Bricks consume a massive quantity of clay. Using clay bricks causes erosion, lowers the water table, and harms the environment. This research examined various waste materials, including fly ash, quarry dust, marble dust, eggshell powder (ESP), and rice husk ash (RHA), in varying percentages to avoid using clay in manufacturing bricks. Compressive strength and water absorption tests were conducted, and the results were compared with the specifications for traditional clay bricks. It was observed that the compressive strength and water absorption values met the relevant standards needed for standard construction bricks. Furthermore, the cost of manufacturing bricks from waste materials was estimated, and the findings show that manufacturing bricks from waste materials cost less than conventional bricks. Finally, it was concluded that the brick industry could become more sustainable and economically feasible by using specific waste materials in manufacturing bricks. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing applications have emerged as a new production method in the construction industry. The materials that are to be used in 3D production process play an important role for a sustainable built environment. The main objective of this study is to design a suitable mixture to produce 3D printed concrete paving stones. In this respect, a unique 3D printer was also developed. The results show that the setting time of cement-based mortars was shortened by increasing the ratio of the added accelerator admixture. However, the optimum mixture proportions for 3D printed concrete paving stones were not reached. The results of the study are expected to develop a sustainable method of paving stone production. [ABSTRACT FROM AUTHOR]

Geopolymer materials are attracting increasing interest from scientists due to their specific properties and the possibility of using waste materials from the power industry for their production. The most common raw material for their production is fly ash from the combustion of hard coal in pulverized coal boilers, but it is also possible to use ash from the combustion of lignite for this purpose. This article presents the results of a study of geopolymers produced with the use of ashes from lignite combustion at the Bełchatów Power Plant. It includes characterization of the ashes (laser particle size analysis, SEM/EDS morphology, XRD phase composition) and the strength properties of geopolymers made from these ashes and activated with 10 M and 14 M aqueous sodium hydroxide solution with water glass. As a result of this study, it was found that it is possible to obtain geopolymers characterized by flexural strength of almost 3 MPa and compressive strength of 30 MPa. A comparison of activators with concentrations of 10 M and 14 M made it possible to conclude that, due to the lack of significant differences in the properties of the obtained geopolymers, from an economic point of view, it is more advantageous in this case to use activators with a lower concentration. [ABSTRACT FROM AUTHOR]

In the study, cement mixtures containing granulated blast furnace slag (GBFS) and siliceous fly ash (SFA) were tested, including those corresponding to special cements according to the PN-B-19707: 2013 standard. Measurements included the period of development of standard strength (up to 28 days) and concerned the compressive strength, linear changes and phase composition of cement mixtures. Furthermore, an evaluation of the microstructure of cement mortar was carried out by SEM. The mixture of composition CEM II/C-M (S-V) satisfies the requirements of the 32.5R or 32.5N strength class, whereas that of CEM VI (S-V) is of the 32.5N strength class, as opposed to stronger mixtures richer in Portland clinker. [ABSTRACT FROM AUTHOR]

In this study, three industrial by-products (ultrafine fly ash, ground granulated blast-furnace slag (ggbs) and circulating fluidized bed co-fired fly ash) were used to produce ternary cementless composites without using alkali activators. The finenesses of ultrafine fly ash, ggbs and co-fired fly ash were 33,800, 5830 and 5130 cm2/g, respectively. The composite material was developed by mixing supplementary cementing materials of different particle sizes and exploiting the high-alkaline properties of the co-fired fly ash to develop a substantial hardening property like cement. The test specimens were made in the form of pastes and the water-to-cementitious-material ratio for the test was fixed at 0.55. The test results show that the flowability of the six different mixtures could be up to 120% and the setting time could be controlled within 24 h. At 60% of the ggbs proportion, the setting time could be held for 8 h. The compressive strength of each proportion reached 7 MPa at 7 days and 14 MPa at 28 days. The water-cured specimens exhibited better strength behavior than the air-cured specimens. Scanning electron microscopy found the main components of strength growth of the specimens to be hydrated reactants of C-A-S-H or ettringite. The results of the XRF analysis show that the specimens responded to higher compressive strengths as the Ca/Si and Ca/Al ratios increased. [ABSTRACT FROM AUTHOR]

One of the measures to reduce the carbon footprint of the Portland cement (PC) manufacturing process is through a wider use of supplementary cementitious and waste materials. The main objective of this work was to produce a new binder using two different waste materials: fly ash (FA) from thermal power plants and spent fluid catalytic cracking catalyst (sFCCC) from petrol refineries. In order to improve their reactivity, both FA and sFCCC were mechanically activated prior to the preparation of the binder. The new binder consisted mostly of the waste materials (70 mass %), with PC as a minor component (30 mass %). It was found that using sFCCC as the binder component accelerated cement hydration and the pozzolanic reaction. The new binder had a shorter setting time and a higher early strength than the binder prepared without sFCCC. [ABSTRACT FROM AUTHOR]

This review presents a mineralogical and physicochemical comparison of coal seams located in the regions of Northwest and Central Greece. The comparison extends to the fly ash derivatives from the coal combustion for energy production, in the cases where data are available. Coal occurrences from Northwest Greece tend to exhibit higher content of rare earth elements (REE) compared to those of Central Greece. Moreover, fly ash products show similar trends in Light-REE compared to their coal parent rocks. The observed REE distribution seems to be correlated with the occurrence of specific minerals such as allanite, monazite, as well as with Fe-contents. [ABSTRACT FROM AUTHOR]

This publication presents the results of a study of the effect of partial replacement of cement with waste and natural materials: ground blast furnace slag, fly ash and lime meal on the strength properties of mortars compared to a reference mortar without these additives. In subsequent tests, these materials were gradually replaced with up to 10% CEM I cement. Their effects on consistency and compressive and flexural tensile strengths after 28 days of maturation were investigated. The tests were carried out on blocks measuring 40 mm × 40 mm × 160 mm according to the standard. In the range of tests analysed, the results obtained make it feasible to consider the possibility of partially replacing cement with silica fly ash and ground granulated blast furnace slag in cement mortars. [ABSTRACT FROM AUTHOR]

Geopolymer composites provide an environmentally friendly alternative to cement-based composites in the construction industry. Due to their distinctive material composition, geopolymers also exhibit electrically conductive properties, which permit their application as a functional material. The current work aims to study the distinctive electrical properties of fly-ash-based geopolymer composites. Varying dosages of graphene oxide (i.e., 0, 0.1, 0.2, 0.3, 0.4% (by wt. of binder)) were introduced into the geopolymer matrix to enhance electrical conductivity. While GO (graphene oxide) is typically less conductive, the interaction of GO sheets with the alkaline solution during geopolymerisation reduced the functional groups and produced cross-linked rGO (reduced graphene oxide) sheets with increased mechanical and electrical conductivity properties. Solid-state impedance spectroscopy was used to characterize the electrical properties of geopolymer composites in terms of several parameters, such as impedance, electrical conductivity and dielectric properties, within the frequency ranging from 101 to 105 Hz. The relationship between the electrical properties and graphene oxide reinforcement can effectively establish geopolymer composite development as smart materials with desirable functionality. The results suggest an effective enhancement in electrical conductivity of up to 7.72 × 10−13 Ω⋅mm−1 and the dielectric response performance of graphene-reinforced fly-ash-based geopolymer composites. [ABSTRACT FROM AUTHOR]

Bricks consume a massive quantity of clay. Using clay bricks causes erosion, lowers the water table, and harms the environment. This research examined various waste materials, including fly ash, quarry dust, marble dust, eggshell powder (ESP), and rice husk ash (RHA), in varying percentages to avoid using clay in manufacturing bricks. Compressive strength and water absorption tests were conducted, and the results were compared with the specifications for traditional clay bricks. It was observed that the compressive strength and water absorption values met the relevant standards needed for standard construction bricks. Furthermore, the cost of manufacturing bricks from waste materials was estimated, and the findings show that manufacturing bricks from waste materials cost less than conventional bricks. Finally, it was concluded that the brick industry could become more sustainable and economically feasible by using specific waste materials in manufacturing bricks. [ABSTRACT FROM AUTHOR]

According to European Union regulations regarding the storage and disposal of industrial waste, waste generated during the treatment of municipal sewage should be managed in an environmentally friendly manner. In order to reduce environmental risks and minimise volume, sewage undergoes thermal treatment. The resulting ash contains toxic components, so it is essential to properly dispose of it. For this reason, the possibility of utilising this type of waste in cement composites has been subject to preliminary verification. To this end, so far, basic tests regarding the parameters such as water demand and setting time have been performed for cement pastes containing ash from the incineration of sludge produced from municipal sewage (Sewage Sludge Ash—SSA). The main purpose of this article is to describe the chemical shrinkage of cement pastes containing this additive. CEM I Portland cement and fly ash obtained at the Thermal Sludge Disposal Station at the Płaszów Sewage Treatment Plant were used in this study. Cement was replaced with ash in the rates of 10%, 20%, and 30%. The results confirm that with an increase in the SSA additive, a reduction of chemical shrinkage of 9.5%, 21.4%, and 31% is observed at 10%, 20%, and 30% content of the additive, respectively. The presented results confirm the possibility of using this material as a cement replacement in cement composites. [ABSTRACT FROM AUTHOR]

Geopolymer materials are attracting increasing interest from scientists due to their specific properties and the possibility of using waste materials from the power industry for their production. The most common raw material for their production is fly ash from the combustion of hard coal in pulverized coal boilers, but it is also possible to use ash from the combustion of lignite for this purpose. This article presents the results of a study of geopolymers produced with the use of ashes from lignite combustion at the Bełchatów Power Plant. It includes characterization of the ashes (laser particle size analysis, SEM/EDS morphology, XRD phase composition) and the strength properties of geopolymers made from these ashes and activated with 10 M and 14 M aqueous sodium hydroxide solution with water glass. As a result of this study, it was found that it is possible to obtain geopolymers characterized by flexural strength of almost 3 MPa and compressive strength of 30 MPa. A comparison of activators with concentrations of 10 M and 14 M made it possible to conclude that, due to the lack of significant differences in the properties of the obtained geopolymers, from an economic point of view, it is more advantageous in this case to use activators with a lower concentration. [ABSTRACT FROM AUTHOR]

The article discusses the possibility of improving the properties of concrete made with composite ash-containing cement (CC) by introducing complex chemical additives. The pozzolanic activity of CC and its degree of hydration increases with the increasing dispersion of cement resulting from the introduction of a complex additive in the form of a polyfunctional modifier (PFM) during grinding, including a grinding intensifier-propylene glycol and a superplasticizer. The analysis of mathematical models of water demand and strength of concrete made with the PFM additive showed that a significant reduction in water demand and an increase in the strength of concrete based on the ash-containing CC is possible with the introduction of the PFM additive. For concrete based on CC with the addition of PFM, it has been demonstrated that it is possible to design concrete mixes on the basis of the obtained models. Relevant examples are provided. [ABSTRACT FROM AUTHOR]

One of the measures to reduce the carbon footprint of the Portland cement (PC) manufacturing process is through a wider use of supplementary cementitious and waste materials. The main objective of this work was to produce a new binder using two different waste materials: fly ash (FA) from thermal power plants and spent fluid catalytic cracking catalyst (sFCCC) from petrol refineries. In order to improve their reactivity, both FA and sFCCC were mechanically activated prior to the preparation of the binder. The new binder consisted mostly of the waste materials (70 mass %), with PC as a minor component (30 mass %). It was found that using sFCCC as the binder component accelerated cement hydration and the pozzolanic reaction. The new binder had a shorter setting time and a higher early strength than the binder prepared without sFCCC. [ABSTRACT FROM AUTHOR]

In the study, cement mixtures containing granulated blast furnace slag (GBFS) and siliceous fly ash (SFA) were tested, including those corresponding to special cements according to the PN-B-19707: 2013 standard. Measurements included the period of development of standard strength (up to 28 days) and concerned the compressive strength, linear changes and phase composition of cement mixtures. Furthermore, an evaluation of the microstructure of cement mortar was carried out by SEM. The mixture of composition CEM II/C-M (S-V) satisfies the requirements of the 32.5R or 32.5N strength class, whereas that of CEM VI (S-V) is of the 32.5N strength class, as opposed to stronger mixtures richer in Portland clinker. [ABSTRACT FROM AUTHOR]

In this study, three industrial by-products (ultrafine fly ash, ground granulated blast-furnace slag (ggbs) and circulating fluidized bed co-fired fly ash) were used to produce ternary cementless composites without using alkali activators. The finenesses of ultrafine fly ash, ggbs and co-fired fly ash were 33,800, 5830 and 5130 cm2/g, respectively. The composite material was developed by mixing supplementary cementing materials of different particle sizes and exploiting the high-alkaline properties of the co-fired fly ash to develop a substantial hardening property like cement. The test specimens were made in the form of pastes and the water-to-cementitious-material ratio for the test was fixed at 0.55. The test results show that the flowability of the six different mixtures could be up to 120% and the setting time could be controlled within 24 h. At 60% of the ggbs proportion, the setting time could be held for 8 h. The compressive strength of each proportion reached 7 MPa at 7 days and 14 MPa at 28 days. The water-cured specimens exhibited better strength behavior than the air-cured specimens. Scanning electron microscopy found the main components of strength growth of the specimens to be hydrated reactants of C-A-S-H or ettringite. The results of the XRF analysis show that the specimens responded to higher compressive strengths as the Ca/Si and Ca/Al ratios increased. [ABSTRACT FROM AUTHOR]

The current study evaluates the influence of the static compaction pressure applied during the casting process on Carbonated Reactive Magnesia Cement-based mortars. For this purpose, mortars, embodying biomass fly ash as filler, were designed and moulded through static compaction pressures of 10, 30, 50, and 70 MPa. The moulded specimens were submitted to an accelerated carbonation curing period of 24 h under controlled conditions. The devised mortars were evaluated through compressive strength tests, and their microstructure was assessed through Mercury Intrusion Porosimetry (MIP), Thermogravimetry and Derivative Thermogravimetry (TG-DTG), and Fourier-transform Infrared Spectroscopy (FTIR) analyses. The results showed that the increment in the static compaction pressure during the specimens' casting process not only led the mortars to reduce their porosity by up to ~30% and increase their compressive strength by up to ~58% (from 19.8 MPa to 31.2 MPa) but also that such a change seems to hinder the CO2 diffusion into the specimens' core, thus resulting in a lower content of carbonated products. In addition, the MIP analyses demonstrated that the static compaction pressure applied in the mortar casting process changes the pores' characteristics, while TG-DTG and FTIR analyses provided evidence that the devised mortars were carbonated to a certain degree. Therefore, this work demonstrated that Carbonated Reactive Magnesia Cement-based mortars are highly influenced by the static compaction pressure applied during the casting process, at least up to a certain value. [ABSTRACT FROM AUTHOR]