Comparative study of Portland cement-based and zeolite-based concretes in terms of hexavalent chromium leaching

The paper presents the results of the leaching study of Portland cement-based and zeolite-based concretes regarding water soluble hexavalent chromium. Three leaching water media (distilled water, rain water, and Britton-Robinson buffer) of various pH values were under investigation. The correlation between pH and leached-out concentrations of chromium was not confirmed. The content of hexavalent water-soluble chromium in leachates of zeolite-based concretes was found to be higher than that in leachates of Portland cement-based samples

Environmental Profile of Building Materials of a Single Family House

A term sustainable is widely used in every branch of human activity including civil engineering. Exploitation of raw materials and natural resources, consuming of energy from non-renewable sources, air, water and soil pollution or creation of massive amounts of waste belong to serious issues of society. Each building process, including extraction of raw material, transportation, production of components, build-up, operation or demolition of buildings poses the negative environment impacts. Besides buildings operation, which is the most energy demanding phase of the life cycle and the phase with the majority of greenhouse and acidifying gasses emissions, selection of material basis is very important. Production of many materials is very non-ecological and requires huge amounts of energy, usually derived from fossil fuels. In this paper materials of a single-family house were analyzed from environmental point of view on the basis of life cycle assessment. Parameters such as amount of used material, global warming potential, acidification potential and primary energy intensity were evaluated. On first occasion the negative influence of build-up was analyzed and the environmental profile of building was created. In the assessed building, amount of primary energy intensity reached 441394.3 MJ, amount of CO2 emissions reached 34953.6 kg CO2eq and SO2 emissions reached 129.9 kg SO2eq. Subsequently, important actions, such as optimization of material base and constructional design should follow to improve the environmental profile of building in terms of used building materials

Characterization of manmade and recycled cellulosic fibers for their application in building materials

The aim of this study was to characterize two types of cellulosic fibers obtained from bleached wood pulp and unbleached recycled waste paper with different cellulose content (from 47.4 percent up to 82 percent), to compare and to analyze the potential use of the recycled fibers for building application, such as plastering mortar. Changes in the chemical composition, cellulose crystallinity and degree of polymerization of the fibers were found. The recycled fibers of lower quality showed heterogeneity in the fiber sizes (width and length), and they had greater surface roughness in comparison to high purity wood pulp samples. The high purity fibers (cellulose content > 80.0 percent) had greater crystallinity and more homogeneous and smooth surfaces than the recycled fibers. The presence of calcite and kaolinite in all of the recycled cellulosic fibers samples was confirmed, whereas only one wood pulp sample contained calcite. The influence of the chemical composition was reflected in the fiber density values. Changes in the chemical composition and cellulose structure of the fibers affected the specific surface area, porosity and thermo physical properties of the fibers. More favorable values of thermal conductivity were reached for the recycled fibers than for the wood pulp samples. Testing the suitability of the recycled fibers with inorganic impurities originating from the paper-making processes for their use as fillers in plastering mortars (0.5 wt.% fiber content of the total weight of the filler and binder) confirmed their application by achieving a compressive strength value of 28 day-cured fiber-cement mortar required by the standard as well as by measured more favorable value of capillary water absorption coefficient.Web of Science7111145112

Comparison of Hexavalent Chromium Leaching Levels of Zeoliteand Slag-based Concretes

In this experiment, the reference concrete samples containing Portland cement as binder and the concrete samples with the addition of ground granulated blast furnace slag (85% and 95%, respectively as replacement of Portland cement) and other samples containing ground zeolite (8% and 13%, respectively as replacement of Portland cement) were analyzed regarding the leachability of chromium. The prepared concrete samples were subjected to long-term leaching test for 300 days in three different leaching agents (distilled water, rainwater and Britton-Robinson buffer). Subsequently, the concentration of hexavalent chromium in the various leachates spectrophotometrically was measured. The leaching parameters as values of the pH and the conductivity were also studied. This experiment clearly shows the need for the regulation and control of the waste addition to the construction materials and the need for long-term study in relation to the leaching of heavy metals into the environment

Leaching of calcium and silicon from cement composites in the aggressive environment

Deterioration of concrete materials exposed to an aggressive solution is often characterized by the leaching of calcium and silicon compounds from the cement matrix. This paper presents the results of the study of concrete composites exposed to the various sulphate environments (sulphuric acid and magnesium sulphate solutions) under laboratory model conditions. The leaching of the calcium and silicon from concrete specimens has been studied during 180 days using X-ray fluorescence method for leachate analysis. As expected, sulphuric acid of pH3 was confirmed to have the most significant effect on the studied ions releasing. The released amounts of analysed ions were 192.2 and 9.6 times higher for calcium and silicon ions, respectively in H2SO4 with pH=3 when compared to fresh water. The concentration of released calcium was 2.6 times highe

Study of thermal analysis of cellulose fibres using into building materials

This paper provides the investigation of thermal analysis of cellulose fibres which will be used into building materials as a partial filler replacement. Cellulosic fibres come from two various sources: bleached wood pulp and unbleached waste paper whereas these natural fibres have different cellulose contents and another manufacturing process. Natural fibres have been widely used as reinforcing fillers in composite materials in recent years. As a result, they are subjected to thermal degradation during composite processing. It is thus of practical significance to understand and predict the thermal decomposition process of natural fibres and the knowledge will help better design the composite process and estimate the influence on composite properties by the thermal decomposition of natural fibres. The results obtained from the thermal analysis of cellulosic fibres showed differences in their thermal decomposition and also differences in the weight loss due to their chemo-mechanical treatment, the presence of impurities and CaCO3 originating from filler in paper making

Study of Thermal Analysis of Selected Cellulose Fibres

This paper provides the investigation of thermal analysis of cellulose fibres which will be used into building materials as a partial filler replacement. Cellulosic fibres come from two various sources: bleached wood pulp and unbleached waste paper whereas these natural fibres have different cellulose contents and another manufacturing process. Natural fibres have been widely used as reinforcing fillers in composite materials in recent years. As a result, they are subjected to thermal degradation during composite processing. It is thus of practical significance to understand and predict the thermal decomposition process of natural fibres and the knowledge will help better design the composite process and estimate the influence on composite properties by the thermal decomposition of natural fibres. The results obtained from the thermal analysis of cellulosic fibres showed differences in their thermal decomposition and also differences in the weight loss due to their chemo-mechanical treatment, the presence of impurities and CaCO3 originating from filler in paper making

Life Cycle Assessment and Environmental Impacts of Building Materials: Evaluating Transport-Related Factors

The construction industry plays a significant role in resource consumption and environmental degradation, making it crucial to analyze the sustainability aspects of construction materials and their transportation processes. This paper focuses on conducting a life cycle assessment (LCA) analysis of building materials, specifically considering the environmental impacts associated with their transportation to construction sites. By incorporating the transport phase into the assessment, a more holistic understanding of the environmental implications of construction materials can be achieved. The study aims to quantify the environmental burdens of both material production and transportation, providing valuable insights for sustainable decision making in the construction industry. The analysis revealed that transport of building materials for the studied house by diesel lorry, covering a distance of 150 km, contributed 16% to climate change and a significant 53.5% to abiotic resource depletion. Additionally, it had a 15–18% impact on acidification and photo-oxidant formation

Impact of calcium ions leaching caused by biogenic acid attack on durability of cement composites

Leaching of calcium ions increases the porosity of cement-based materials, consequently resulting in a negative effect on durability since it provides an entry for aggressive harmful ions, causing corrosion of concrete. Sulphuric acid corrosion of concrete can be caused due to attack of aggressive media naturally existing in the environment. Another possibility of corrosion formation is biogenic acid effect through the agency of microorganisms. The paper is focused on the investigation of the influence of biogenic acid attack on the cement composites affected with bacteria Acidithiobacillus thiooxidans. The concrete specimens with 95% wt. addition of antimicrobial activated granulated blast furnace slag as durability increasing factor as well as without any addition were studied. The experiments proceeded during the nine 7-day cycles. The pH values and chemical composition of leachates were measured and evaluated after each cycle. The higher resistance of concrete samples with the addition of 95% wt. of antimicrobial activated granulated blast furnace slag to the aggressive environment was confirmed. The leaching of calcium ions of concrete sample affected with bacteria Acidithiobacillus thiooxidans was 1.13 times lower (736.6 mg/L of leachate) for concrete sample with antimicrobial activated granulated blast furnace slag addition comparing to concrete sample of ordinary CEM I Portland cement without any additives (832.0 mg/L of leachate)

Rapid Chloride Permeability Test of Mortar Samples with Various Admixtures

This paper is focused on the permeability of cement composite samples with various admixtures. Permeability was examined by the rapid chloride permeability test due to the simple and relatively quick performance among the many methods. Permeability is one of the durability parameters considering the pore system of the composite structure. Ion diffusion provides information about inner pore structure by passing a charge through the sample. In real-life conditions, not only chlorides but also other ions can penetrate into the structure and cause corrosion. Various cement supplements were used as admixtures. The reference sample consisted of cement, fine sand, and water, while the rest of the samples consisted of 20% blast furnace slag, bypass dust, eggshells or recycled glass instead of the cement. The results showed lower permeability in samples containing blast furnace slag and eggshells and a higher charge passage in samples with recycled glass and bypass dust than for the reference sample