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

Effectiveness of Concrete Reinforcement with Recycled Tyre Steel Fibres

The role of searching for industrial waste management solutions in construction is key for environmental protection. Research in recent years has focused on solutions aimed at reducing the carbon footprint. This paper presents the results of tests conducted on concrete reinforced with treated recycled tyre steel fibres (RTSFs) compared to the same amount of manufactured steel fibres (MSFs). The effectiveness of concrete reinforcement with RTSFs was analysed using the fracture mechanics parameters of cementitious composites. Rheological tests, residual flexural tensile strength tests, work of fracture measurements, toughness indices, examinations of the fibre distribution in the concrete, and SEM observations of the concrete fractures with fibres were performed. Determining the work of fracture and toughness indices was an innovative aspect of this paper. As the amount of RTSFs increased, a decrease in the consistency was observed, although the distribution of fibres in the concrete was uniform, as proven by the results of computer tomography tests. Concrete reinforced with RTSFs that is purified and refined during the recycling process might have better properties than concrete reinforced with the same amount of MSFs. The application of RTSFs in construction has environmental and economic benefits in addition to the strengthening of cementitious composites

Ammonia in Fly Ashes from Flue Gas Denitrification Process and its Impact on the Properties of Cement Composites

The paper presents the results of research on the properties of fly ashes from the process of flue gas denitrification by selective non-catalytic reduction (SNCR), consisting of dosing urea into the coal combustion chamber. The research was carried out on two types of fly ash: Silica fly ash from flue gas denitrification and ash from a traditional boiler without the flue gas denitrification process. The scope of comparative studies included physicochemical and structural features of ashes, as well as slurries and mortars with the addition of ashes. Fly ash from denitrification, whose ammonia content at the time of sampling was 75 mg/kg at the maximum, was examined. Our own research has shown that fly ash from flue gas denitrification is characterized by a higher value of losses on ignition and ammonia content in comparison to ashes without denitrification. It was shown that the ammonia content in the analyzed range does not limit the use of fly ash as an additive to cement and concrete

The Role of Spontaneous Flora in the Mitigation of Particulate Matter from Traffic Roads in an Urbanised Area

Particulate matter (PM) is a serious air pollutant that poses significant health risks. One solution to reduce PM concentrations in these areas is through phytoremediation, a process that involves using plants to remove contaminants from the environment. In this study, we investigated the capacity of spontaneous flora—herbaceous plants, shrubs, and trees growing in five zones from the road—to absorb PM on their foliage. The study found significant differences in the accumulation of PM, with the highest PM accumulation recorded in Zone V, which boasted a blend of the three mentioned vegetation types together. In contrast, Zones I and II, which were located close to the road and comprised solely herbaceous plants, exhibited 14.3% and 43.4% less PM accumulation, respectively. Similarly, Zone IV, with a mix of herbaceous plants and shrubs, showed 64.5% less PM accumulation, while Zone III, with only herbaceous plants, had a staggering PM accumulation reduction of 76.8%. The sum of Si+Al+Ca displayed a similar pattern. Furthermore, the findings highlighted the valuable role of plants in decreasing PM concentrations in the air, resulting in reductions of 76%, 39%, and 47% for PM10, PM2.5, and PM1.0, respectively. The results indicate that various spontaneous flora can work in unison to reduce PM, providing a multifaceted approach to combating air pollution

The Water Flow Regime in the Weir Area for Vascular and Rush Plant Species Composition

The hydrotechnical construction, damming up the riverbed, creates two zones of hydraulic conditions, which affect the water discharge and sediment transport routes, as well as plant species composition, as a habitat answer to the hydraulic regime. This study examined the diversity of the vascular and rush plant species upstream and downstream of the weir. The Świder River, a small lowland river in Central Poland, was chosen as a study area. An examined river reach was located at 21 + 340 kilometers of the Świder River. Vegetation properties, plant species, and granulometric fraction composition were recognized at chosen cross-sections along the riverbed where specific hydraulic conditions could be met. The spatial distribution of vortices, smooth or rapid flow areas, and velocity pulsations influence the biotic environment, thereby affecting the species composition, quantity, and plant diversity. In the headwater zone, an environment more favorable to grain accumulation could be met, which was mixed with organic components in an agricultural catchment area. This phenomenon leads to creating favorable conditions for increased biodiversity. The present study demonstrated that small weirs could positively affect the composition of vascular and rush plants

Not Only Trees Matter—Traffic-Related PM Accumulation by Vegetation of Urban Forests

In terms of the process of air purification, a lot of attention has been devoted to trees and shrubs. Little attention has been paid to herbaceous vegetation from the lower forest layers. Urban forests are often located on the outskirts of cities and surround exit roads where there is heavy traffic, generating particulate matter (PM) pollution. The aim of this study was to investigate the spread of PM from the road traffic in the air and to investigate how individual layers of urban forests accumulate PM. We conducted comparative analyses of PM accumulation on plants in five zones away from the road, into the forest, in the air, and in four vegetation layers: mosses, herbaceous plants, shrubs and trees. The results show that all forest layers accumulate PM. We show that PM is very efficiently accumulated by herbaceous plants growing along roadsides, and that the PM that was not deposited on herbaceous plants was accumulated by trees and shrubs. With increasing distance from the road into the forest, the PM content on herbaceous plants decreased and the accumulation on trees and shrubs increased. We estimated that PM concentration in the air dropped significantly in the front line of the trees, but it was still detectable up to 50 m into the forest. The results presented herein show that meadow vegetation and urban forests play a very important role in air purification. Our results provide a better understanding of the complexity of urban forest interactions and provide the basis for better planning of urban greenery

Impact of Forest Landscape on the Price of Development Plots in the Otwock Region, Poland

Building plots, understood as land properties intended for development, are an important object of commercial transactions. Their prices are determined by several factors, such as location, state of development, distance from important urban centres, and proximity to green areas. It is certain that, especially with regard to building plots intended for single-family housing, the proximity of natural areas, especially forest areas, is becoming increasingly important. The Otwock region, with a forest cover of more than 30%, has numerous undeveloped lands that are or could be development plots. This article concerns an analysis of transactions involving undeveloped development land of selected communes in the Otwock region. On the basis of an analysis of prices of real estate transactions from 2011 to 2016 from four municipalities of the Otwock region and a spatial visualisation of the plots, the relationship of price (m2) with physical characteristics (technical development, shape, area), distance from a large city (Warsaw), and distance from a railroad line stop and landscape values (landscape type, distance to the forest, number of landscape components) was determined. Statistical analyses used regression and correlation analysis. The preferences of 519 people interested in buying/selling real estate in the Otwock region were also investigated, and for this purpose, we cooperated with real estate offices and municipal offices. The results of the survey strongly indicate that forest landscapes increase the attractiveness of building plots, which in turn leads to higher prices on the market. The results of the study show that there is a relationship between the price of a property and its distance to the forest, the nature of the forest boundary, and the number of landscape elements. The forest landscape is one of the most important factors determining the attractiveness of a building plot. Proximity to a forest, especially forests under a form of protection, is an important value for prospective land plot buyers. The views of respondents varied considerably due to socio-demographic characteristics, mainly the age and education of respondents

Impact of Forest Landscape on the Price of Development Plots in the Otwock Region, Poland

Building plots, understood as land properties intended for development, are an important object of commercial transactions. Their prices are determined by several factors, such as location, state of development, distance from important urban centres, and proximity to green areas. It is certain that, especially with regard to building plots intended for single-family housing, the proximity of natural areas, especially forest areas, is becoming increasingly important. The Otwock region, with a forest cover of more than 30%, has numerous undeveloped lands that are or could be development plots. This article concerns an analysis of transactions involving undeveloped development land of selected communes in the Otwock region. On the basis of an analysis of prices of real estate transactions from 2011 to 2016 from four municipalities of the Otwock region and a spatial visualisation of the plots, the relationship of price (m2) with physical characteristics (technical development, shape, area), distance from a large city (Warsaw), and distance from a railroad line stop and landscape values (landscape type, distance to the forest, number of landscape components) was determined. Statistical analyses used regression and correlation analysis. The preferences of 519 people interested in buying/selling real estate in the Otwock region were also investigated, and for this purpose, we cooperated with real estate offices and municipal offices. The results of the survey strongly indicate that forest landscapes increase the attractiveness of building plots, which in turn leads to higher prices on the market. The results of the study show that there is a relationship between the price of a property and its distance to the forest, the nature of the forest boundary, and the number of landscape elements. The forest landscape is one of the most important factors determining the attractiveness of a building plot. Proximity to a forest, especially forests under a form of protection, is an important value for prospective land plot buyers. The views of respondents varied considerably due to socio-demographic characteristics, mainly the age and education of respondents