Effectiveness of Curing Compounds for Concrete.

Curing compounds are widely used materials that are used in place of other methods of curing fresh concrete. The article presents an overview of the effectiveness of the concrete curing compounds widely used in Europe. Eleven different products have been tested. FTIR spectroscopy identification tests showed that all tested products might be divided into two main groups, depending on the type of their active substance. The water retention efficiency of each curing compound was examined, and the tensile strength of the cured samples was tested using the pull-off method. The dry mass content of the tested products was examined to check for a correlation between their effectiveness and active substance content. The microstructure of mortars treated with the most effective compounds and the reference mortar were examined using SEM techniques. Significant differences in microstructure were found between cured samples with different curing compounds, and also with uncured samples.

Identification of Olfactory Nuisance of Floor Products Containing Bitumens with the TD-GC-MS/O Method.

The adopted TD-GC-MS/O method helps determine the correlation between the odour signals and compounds separated on the chromatographic column, from the analysed gas mixture. It is possible to compare the retention times at which the odour signals were identified with the retention time of eluting compounds, when the test system and matrix are known. The presented study describes the details of representative samples obtained from (1) indoor air samples from a room where floor materials containing bitumen are present, (2) wooden floor staves placed in an emission chamber, and (3) fragments (chips) of the materials mentioned above, placed in glass tubes, exposed to an elevated desorption temperature. The results, presented in the paper, describe the identified odours and their intensity and assign chemical compounds to each odour, indicating their likely source of origin. The results presented in the manuscript are intended to show what methodology can be adopted to obtain intense odours from the tested samples, without losing the sensitivity derived from GC-MS. The manuscript presents representative results-case studies. The results for various types of samples were not very reproducible, related to the complex matrix of bituminous products. The enormity of compounds present in tar adhesives makes it possible to indicate only the groups of compounds that emit from these systems. They include, primarily, aliphatic, aromatic and heteroaromatic hydrocarbons, particularly Naphthalene and Phenol derivatives.

Leaching and VOC Emission Tests of Polymer Composites Produced from Post-Consumer Waste in Terms of Application in the Construction Sector.

One of the existing priorities of the European Union is to search for rational waste management and to keep such waste in the economic cycle, while meeting the highest safety requirements. The paper presents the results of environmental tests of composites based on the polyethylene (rPE) and polypropylene (rPP) matrix and reinforced with cellulose fibres (newsprint, NP). Raw materials were obtained by recycling post-consumer waste such as beverage bottles and newsprint. The composites were tested for their potential use as materials in cladding panels and acoustic barriers. Given that normative documents for these products do not define specific environmental requirements, the composites were tested for the release of dangerous substances, such as anions of inorganic compounds, heavy metals, volatile organic compounds (VOCs), and their impact on the environment. A detailed in-depth analysis of the mechanisms of release of substances (diffusion, dissolution, surface leaching and depletion) from the rPP/NP composite into surface water, groundwater and soil was carried out. In turn, emission of VOCs from the rPE (low-density:high-density (LD:HD)-50:50) and rPE (LD:HD-30:70) composites into indoor air was also carried out. Raw materials in the form of granulates and loose cellulose fibres, used to produce the composites, were also tested for their environmental impact.

Comparison of VOC Emissions Produced by Different Types of Adhesives Based on Test Chambers.

Volatile organic compounds (VOCs) emitted from building materials into the indoor air may cause discomfort associated with a perceptible chemical odour and may irritate the upper respiratory tract. Hence, it is vital to control indoor air pollution sources, such as interior finishing materials, including adhesives. The study involved carrying out a series of experimental tests of VOC emissions of 25 adhesives based on the ISO 16000 series standards. The research concerns three groups of construction adhesives with indoor applications, i.e., flooring (10), finishing walls and ceilings (6), and for other applications such as edge-gluing or gluing tiles or mirrors (9) differing in chemical composition. A series of temperature tests were carried out for a representative floor adhesive at selected temperatures: 25 °C, 35 °C and 45 °C. The theoretical correlation approach was adopted to characterise the relationship between the emission rate and temperature of selected chemical compounds.

Materials Contamination and Indoor Air Pollution Caused by Tar Products and Fungicidal Impregnations: Intervention Research in 2014-2019.

Construction materials containing tar products are a source of indoor air pollution in buildings. This particularly concerns old buildings, in which wooden structures were impregnated with tar compositions (creosote oil and Xylamite oil containing tar products) and buildings in which bituminous seal containing hydrocarbon solvents was used. During the 1970s and 1980s, an impregnant known as Xylamite was commonly used in Polish buildings. This material still emits organic vapors into the building's environment, significantly worsening indoor air quality (IAQ). Xylamites and other impregnating materials are a source of indoor air pollution through toxic organic compounds, such as phenol, cresols, naphthalenes, chlorophenols (CPs), and chloronaphthalenes (CNs), which emit specific odors. TD-GC/MS enables detailed identification of the reasons behind chemical indoor air pollution. The results of laboratory tests on the chemical emissions of bitumen-impregnated materials were presented in 32 case studies. In turn, the results of indoor air pollution by volatile bitumen components were presented on 11 reference rooms and 14 case studies, including residential buildings, office buildings, and others. Laboratory tests of samples of construction products confirmed the main emission sources into indoor air. The research results for the period 2014-2019 are tabulated and described in detail in this manuscript.

Identification of MVOCs Produced by Coniophora puteana and Poria placenta Growing on WPC Boards by Using Subtraction Mass Spectra.

Volatile fungal metabolites are responsible for various odors and may contribute to a "sick building syndrome" (SBS) with a negative effect on the heath of building. The authors have attempted to fill the research gaps by analyzing microbial volatile organic compounds (MVOCs) originating from representatives of the Basidiomycetes class that grow on wood-polymer composite (WPC) boards. WPCs have been analyzed as a material exposed to biodeterioration. Indoor air quality (IAQ) is affected by the increased use of WPCs inside buildings, and is becoming a highly relevant research issue. The emission profiles of MVOCs at various stages of WPC decay have been demonstrated in detail for Coniophora puteana and Poria placenta, and used to set the European industrial standards for wood-decay fungi. Differences in the production of MVOCs among these species of fungi have been detected using the thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) method. This study identifies the production of alcohols, aldehydes, ketones, carboxylic acids and other compounds during one month of fungal growth. The identified level of metabolites indicates a relation between the level of air pollution and condition of the WPC material, which may become part of IAQ quantification in the future. The study points to the species-specific compounds for representatives of brown and white-rot fungi and the compounds responsible for their odor. In this study, 1-Octen-3-ol was indicated as a marker for their active growth, which is also associated with SBS. The proposed experimental set-up and data analysis are a simple and convenient way to obtain emission profiles of MVOCs from microbes growing on different materials.

The ring-stage of Plasmodium falciparum observed in RBCs of hospitalized malaria patients.

Raman spectra of the blood samples obtained directly from hospitalized malaria patients with Plasmodium falciparum (P. falciparum) in the ring-stage were analyzed. Changes observed in the Raman band intensities of the infected patients compared to healthy volunteers are the result of parasite activity inside red blood cells. The obtained spectra were discussed by analyzing differences in particular spectral regions by evaluating changes in the band intensity ratios as well as using PCA analysis. The alterations of erythrocyte membranes caused by parasite penetration are visible by a reduced I1130/I1075 intensity ratio expressing the lowering of the amount of domains arranged in trans conformation. The I2930/I2850 ratio, which is a measure of modifications in structures of membrane proteins and lipids, in infected red blood cells increases, which is caused by malaria protein export to the erythrocyte membrane and expresses the membrane disarrangement. In the pyrrole ring vibration region, the ν4 band marker of the oxygenated-Hb shows at 1371 cm(-1) whereas the ν4 band at 1353 cm(-1) related to the deoxygenated-Hb is observed for malaria patients and is characterized by a higher intensity in infected erythrocytes. The amide I analysis shows the modifications in the secondary structure composition in the infected RBCs. We found that the P. falciparum infection leads to a decrease in the α-helical content and a concurrent increase in undefined (random-coil) structures. It was observed that the Raman spectra changes are also the result of the hemozoin formation process. In the pyrrole ring stretching vibration region, the increase of 1220 cm(-1) (deoxyHb) as against 1248 cm(-1) (oxyHb) may be considered as a signal of hemozoin formation in the RBCs. Relatively intense band patterns at 1560 cm(-1) and also at 1570 cm(-1) and 1552 cm(-1) may be due to the hemozoin that is formed according to parasite activity. The results of medical diagnostic tests had not presented changes in patient RBC parameters. A significant reduction in WBC count was noticed along with a decrease in neutrophil and platelet count when compared with the control group. Although no change is observed in the overall picture of the erythrocytes, pathological changes are evident in the Raman spectrum.