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Two different types of modified lime mortars were prepared, namely salt-resisting and salt-absorbing, to determine their chloride binding capacity. The results were compared with reference pure lime mortar. The difficulty of measured chloride binding isotherm presentation was discussed and data confrontation was performed. From that point of view, the salt binding capacity of materials should be considered as relative value depending on the method of data evaluation and assessment. [ABSTRACT FROM AUTHOR]

Measurement and assessment of thermo-physical properties of magnesium oxychloride cement (MOC) with implemented phase change material based on paraffin wax encapsulated in polymer shell, is presented in the paper. The measurement method and mathematical interpretation of thermal conductivity and specific heat capacity assessment was derived from the Thermophysical Transient Tester 1.02 that was developed at the Institute of Physics, Slovak Academy of Sciences. Within the test, thermal responses between two thermal sources were measured during the step wise heat reference source and source generating step wise heat. It was revealed that both investigated thermal parameters depend on the dosage of PCM in composite mixture, thus porosity of prepared materials and thermal characteristics of PCM itself. The obtained data point to the substantial improvement of heat storage capacity of MOC by the use of powdered PCM. [ABSTRACT FROM AUTHOR]

The presented study is focused on a novel approach in the design of composites based on magnesium oxychloride cement (MOC) material as alternative to construction materials widely used in building industry. The base of this approach lies in the enhancement of the MOC-matrix using tannic acid and carbon-based nanomaterials, namely graphene nanoplatelets and multi-walled carbon nanotubes. The use of the carbon nanomaterials in very low content is beneficial for the mechanical and macrostructural parameters of the composite, whereas the tannic acid was added for its possible ability to improve not only mechanical performance, but also the water resistance of the composite. A reference MOC sample, MOC with tannic acid sample and MOC with tannic acid and combination of graphene nanoplatelets and multi-walled carbon nanotubes were prepared and studied. All of the additives proved themselves beneficial for the matrix, resulting in a formation of composite applicable e.g., in construction industry. [ABSTRACT FROM AUTHOR]

Historical masonry structures usually suffer from harmful salt and moisture action that together with environmental conditions negatively affect their performance, functionally, and durability. The results of deterioration processes attributed to salt first appear on the surface of building elements, most often in plastering and rendering mortars. However, as the salt sources are mostly identified in masonry materials themselves, it is necessary to understand salt transport and storage in base materials to get valuable and crucial information for application of repair mortars and other surface treatments. Therefore, transport and accumulation of dissolved chloride ions in materials frequently used in the Europe for historical masonry, i.e. ceramic brick and sandstone, was investigated. The fully water-saturated samples of the studied materials were penetrated by NaCl solution. The transport of chlorides was characterized by diffusion coefficient considering the chloride interaction with the porous system of the studied materials. An inverse approach to experimentally measured chloride profiles was used to calculate the chloride diffusion coefficient, while the transport of chloride ions was described by a simple diffusion and diffusion-advection model. [ABSTRACT FROM AUTHOR]

In order to meet increasing requirements on mechanical strength of lime-based materials, modification by carbon-based nanoadditives seems as the proper enhancement strategy. However, the incorporation technique preventing clusters formation and ensuring proper distribution in fresh mixture is crucial for effective application of nanomaterials in production of construction composites. On this account, the dispersing effect of surfactant combined with antifoaming agent and its impact on mortars based on natural hydraulic lime and enhanced with multiwalled-carbon nanotubes (CNTs), have been analyzed. Dispersing solutions have been tested on foam formation, foam stability and UV-light absorption to evaluate dispersing effect. Impact of the used dispersing solution on hardened mortar samples was evaluated based on the assessment of basic structural and mechanical parameters. While CNTs dispersed in water starts to form clusters immediately after mixing stops, the dispersion stability was greatly enhanced with use of surfactant. On the other hand, surfactant stabilized air bubbles formed during mixing of mortars and resulted in an increased porosity accompanied by a low mechanical strength. The best results were achieved with the use of surfactant increasing dispersion effect in combination with the antifoaming agent which effectively destabilized formed air bubbles. [ABSTRACT FROM AUTHOR]

Masonry, rendering, and plastering mortars are during their lifetime impressed with many harmful factors that negatively affect their functional, technical, and durability parameters. Inorganic salt and water are considered as the most aggressive agents damaging mortars and other inbuilt structural materials. The excessive salt presence and high moisture content are typical especially for older buildings, where water-proof horizontal insulation is missing or in the case of accidents of water or sewage pipeline, flooding, improper restoration treatments, buildings usage, etc. Except salt crystallization, their hygroscopicity represents serious risk for material vulnerable to moisture induced damage. On this account, the analysis of hygroscopic behavior of non-hydrophobized mortars that should find use in masonry repair is the subject of the presented research. The examined mortars were produced from different type of binder: i) lime hydrate, ii) natural hydraulic lime, iii) lime-cement blend, and zeolite, which fully replaced silica sand in reference samples. The basic characterization of mortars was done by the assessment of their structural parameters, mechanical and thermal properties. Specific attention was paid to the analysis of water vapor storage capacity of mortars, which was done by the measurement of sorption and desorption isotherms. The use of zeolite enabled to produce highly porous mortars with sufficient mechanical strength and high sorption capacity for water vapor which can find use in passive control of indoor climate. According to IUPAC classification, the sorption/desorption isotherm were of type IV, i.e. with hysteresis loop and obvious capillary condensation. [ABSTRACT FROM AUTHOR]

With the rapid growth of the population and urbanization, the demand for industrial production has continued to increase, and industrial solid waste has become more and more abundant. Industrial solid waste mainly includes fly ashes, slags, tailings, red mud, bottom ashes and other wastes, which account for approximately 80% of the total waste produced on Earth. Industrial wastes generally contain various heavy metal components such as Pb, Zn, Cu, Cd, Cr, As, Ba and Mn. The low recycling rate of solid waste results in significant land use for disposal, and the heavy metals and alkaline substances contained in solid waste spread pollution through weathering in the form of dust and leaching into soil and groundwater resources, leading to water contamination and land salinization. Heavy metal pollution not only has a negative impact on soil and water quality, but also gradually accumulates in the human body, causing serious health problems and diseases, such as Parkinson's disease, muscular dystrophy, and Alzheimer's disease, while some metals can even cause cancer. Contamination by heavy metals and other solid wastes poses serious consequences for the environment and sustainable development and, in the longer term, essentially threatens the very existence of an industrial and prosperous human society. Coal is the world's most abundant fossil fuel accounting for approximately 70% of the world's total proven fossil fuel resources. Coal combustion produces not only common pollutants such as SOx, NOx and dust, but also highly toxic heavy metal pollutants. As heavy metals in coal have the characteristics of low content, large total emission, easy to migrate and difficult to degrade, which cause a great harm to human body and environment, there is necessary to control the emission of heavy metals from coal combustion and treat them in a safe way. On that ground the use of fly ash (FA) from coal combustion in a cement-based composite intended for the construction industry, combined with the immobilization of heavy metals in the final product, may be a suitable solution to this problem. In this study, the immobilization of As, Ba and Cu contained in fly ash from coal combustion was experimentally investigated. Fly ash was used to replace 10 wt.% and 20 wt.% of Portland cement (PC) and 0-2 mm silica sand was used as an aggregate. The evaluation of the basic physical and mechanical properties was carried out. Special attention was paid to the evaluation of the immobilization of the studied heavy metals in the prepared composites; the leaching test was performed with a liquid/solid ratio of 10 L/kg. The concentration of As, Ba and Cu in the leachates was analysed by atomic absorption spectroscopy (AAS). The results showed that the concentrations of the studied heavy metals in the leachates of the prepared composites were very low, which suggests that they were completely immobilized in the matrices. The mechanical resistance of the prepared mortars was slightly reduced by PC substitution by FA, but from the quantitative point of view it remained high enough for practical use of prepared composites in development of "green" building materials. [ABSTRACT FROM AUTHOR]

In view of the growing population and urbanization, it is necessary to ensure the development of advanced building materials capable of ensuring the quality of living conditions with as low energy consumption as possible. A proven way to achieve this is to create a composite material with a lightweight aggregate. However, the use of lightweight aggregate could also affect other material properties, such as mechanical strength or water absorption. In this study, the silica sand aggregate was partially and completely replaced with foam glass gravel in the composition of natural hydraulic lime plasters in order to reduce thermal conductivity of the material. The use of foam glass is also profitable with regard to the environmental aspect, due to its recyclability. The effect of application of glass gravel on the structural properties, mechanical strength, thermal properties, and water transport parameters was studied for 28-days cured samples. According to the results, the application of foam glass gravel significantly reduced the thermal conductivity of the plaster while maintaining its sufficient strength despite the increase in high porosity, even when the silica sand aggregate was fully substituted. Based on the data obtained, it was concluded that the use of foam glass as a filler is beneficial in improving the thermal properties of plastering mortars. [ABSTRACT FROM AUTHOR]

This contribution deals with design and development of magnesium oxychloride cement (MOC) composites for extraterrestrial application. For the design of the composite, Martian soil simulant MGS-1 was used as a filler, in order to form a composite, which uses materials available at the locality of application. The designed composite contained 5 wt. % of MGS-1 (relatively to the content of MgO) and was prepared with two types of raw MgO powder with different purity. Overall four types of MOC-based material were prepared, analyzed using multiple types of analytical methods and mechanical tests and compared with each other. The influence of the Martian soil simulant on the MOC matrix was assessed, showing the high potential of such material in its intended environment of application. [ABSTRACT FROM AUTHOR]

Rendering and plastering mortars designed for repair of masonry are often exposed to harmful conditions, whereas salt weathering represents serious risk for mortars durability and functional performance. Due to their nature, inorganic salts are highly hygroscopic substances which must be always considered in the case of the salt-contaminated building materials. In the presented research, structural and thermal parameters of lightweight mortars with zeolite aggregate were tested. The assessment of sorption/desorption isotherms which were experimentally measured and analyzed was of the particular importance. Fort the measurement, the static desiccator method combined with precise laboratory balances was used. Before the hygroscopicity analysis, the samples went through the salt crystallization test which was conducted by the use of NaCl water solution. In this way, salinization of samples was reached. The results obtained showed a significant increase in sorption capacity due to the used lightweight aggregate (zeolite) and the presence of salt in the pores of the mortars. [ABSTRACT FROM AUTHOR]

Although the non-hydraulic slaked lime has been already discovered in ancient times, it finds use in repair applications nowadays. However, compared to other generally used binders, i.e., hydraulic lime and Portland cement, slaked lime is characteristic by a low hardness. To improve the overall performance of lime-based materials, the enhancement with graphene nanoplatelets as nanoadditive has been tested. In addition to control lime-based mortar, two mixtures enriched with 0.5 wt.% and 1.0 wt.% of graphene were prepared and tested. Hardened mortars were subjected to variety of tests to analyze their basic structural characteristics, mechanical performance, and water absorption. The particular tests were conducted for 28-days and 360-days samples. Additionally, heat transport and storage parameters of 360-days samples were measured with a hot-disk transient plane source technique (TPS) and the effect of mortars hygroscopicity, thus moisture content, was considered. Before the heat transport and storage testing, the samples were exposed to humid environment using a static desiccator method. The obtained data gave evidence of improvement of mechanical performance of mortars with used nanoadditive. On the other hand, low dosage of graphene nanoplatelets combined with their imperfect distribution had no substantial effect on water absorption and mortars hygroscopicity. Both tested thermal parameters were moderately affected by moisture presence. [ABSTRACT FROM AUTHOR]