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<p>This research investigates as chemical and mineralogical properties can affect degradation of concrete, made using secondary aggregates derived from recycled, in the enforcement of Waste Framework Directive (WFD) 2008/98/EC. High volumes of C&D require the use of waste in various productive contexts. The utilisation of secondary materials derived from CDW recycling in flooring of industrial warehouse can reduce the environmental impacts of quarrying extractions. In recent years, the use of waste in the packaging of mortars and conglomerates has been increased and many companies offer the incorporation of waste glass as aggregate for concrete and mortars. There is still scientific debates on the opportunity to use glass related to the influence on workability and there are some concerns on the durability and resistance to degradation of products made with non-natural aggregates in conditions of interaction with alkali-rich waters.</p><p>In this work mineralogical-petrographical analyses have been carried out on sample and have shown that:</p><p>- use of glass influences compaction factors, therefore there is an increase in the air content also due to the involvement of numerous small particles. This produces high macroscopic and nanometric porosity, observed both on thin sections microscope observations and on SEM-EDSanalyses, which affects compressive, tensile and flexural strength of mortars and concrete in proportion to the content of waste glass used.</p><p>- microcracks in glass aggregates, produced by crushing, increase aggregate water interaction surface, so it tends to degrade more easily by hydrolysis, moreover the greater permeability to air and water accelerates carbonation processes.</p><p>- smooth surface of the waste glass decreases the adhesion force between glass surface cement.</p><p>- addition of waste glass to natural aggregates produces an improvement in workability due to the non-absorbent nature of the glass.</p><p>- In the short time inclusion of glass aggregates effectively improves the surface resistivity and the attack on sulphate but in the long time a secondary porosity for hydrolysis intervenes and the resistance decreased, and the carbonation rate increases.</p><p>- contraction from drying of the concrete decreases with the content of glass aggregates increasing, but subsequently the swellings by hydrolysis can produce a secondary porosity giving an intimate and widespread fracturing of the matrix</p><p>Petrographical both on thin sections and on crushed samples observation and SEM-EDS microanalysis have shown that degradation is due to the use of crushed natural aggregate mixed with recycling aggregate rich in common glass. This degradation has provided that alkaline elements interact with cement and with siliceous aggregates of the screed. It has been also noted that degradation is accelerated by the widespread presence of sulphur, sometimes in high concentrations and due to the use of recycled material, and the presence of iron. Degradation differences depend on a heterogeneous distribution of the C&D waste aggregate, so in the areas where it is less abundant, the phenomenon is less striking.</p>

Bron: https://doi.org/10.5194/egusphere-egu2020-13887

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Following World War II, the swift economic growth in construction and the soaring demand in urban regions led to the excessive extraction of natural resources like fossil fuels, minerals, forests, and land. To tackle significant global challenges, including the consumption of natural resources, air pollution, and climate change, radical changes have been suggested over the past decades. As part of this strategic initiative, prioritizing sustainability in construction has emerged as a crucial focus in the design of all projects. In order to identify the most environmentally sustainable reinforced concrete (RC) slab system, this research investigates the carbon emissions associated with various slab systems, including solid, voided slabs and precast floor systems. The results demonstrate that beam and slab floor and solid slabs have the highest embodied carbon due to the significant use of concrete and related materials, whereas voided slabs and two-way joist floors exhibit lower carbon emissions. The results indicate that the two-way joist system is the most environmentally advantageous option. For precast floor systems, post-tensioned concrete and hollow-core slabs demonstrate the lowest embodied carbon levels. This research provides practical recommendations for architects and engineers aimed at enhancing sustainable design methodologies. It emphasizes the importance of incorporating low-carbon materials as well as pioneering flooring technologies in upcoming construction initiatives to support the achievement of global sustainability objectives.

Bron: https://doi.org/10.20944/preprints202502.0687.v1

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Flooring materials and adhesives can be degraded by high pH moisture from e.g. concrete. One way to avoid this degradation, is to dry the concrete and the screed to a sufficient moisture state prior to application of the flooring material. One way to evaluate the moisture state in the materials sensitive to high pH moisture is to calculate the redistribution of moisture in the flooring system from application and onwards. The calculations require substantial knowledge in both moisture related material properties and mass transport calculations in porous materials. The availability of more user-friendly calculations tools stresses the need for a common methodology for both performance and documentation of the calculations. Several input parameters are needed for the calculation, such as boundary conditions, initial moisture distribution and material properties. The most important material properties are the water vapor sorption isotherms (desorption, absorption and scanning) and moisture transport coefficients. This study is investigating the sensitivity of the moisture redistribution calculations to different input parameters, and assumptions needed for the calculation. It is also clarifying what relative humidity intervals that are relevant for different materials in the system and identifying a required accuracy in the different material properties. A first part of round-robin studies with selected cases has been performed to evaluate difference between calculations tools and users.

Bron: https://doi.org/10.1051/e3sconf/202017204008

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Due to new environmental trends and restrictions and due to more interest in using renewable materials with circularity, wood has become an important group of building materials. In Scandinavia, wood is a preferred building material where wooden laminates and parquet flooring are extremely popular in housing. Since wood contain terpene compounds and the flooring materials use a lot of adhesives to obtain different structures depending on if it is a parquet or a laminate flooring, it is of interest to investigate how such materials influence the indoor air quality (IAQ) and if the emitted compounds may contribute to health problems. In this study, primary emissions from several commercially available wooden flooring materials such as parquet and laminated flooring are presented. Since indoor air climate is very much dependent on the emission of volatile organic compounds from the building materials, we investigated such materials from the point of view of emission of volatile organic compounds and aldehydes. Since aldehydes are more toxic, it is of interest to review some of such data for aldehydes in this paper, which are necessary to obtain good indoor air quality. Health risks may mainly arise from the emission of terpene compounds and aldehydes from such flooring materials. According to international Occupational Exposure Limit levels (OEL), aldehydes are very hazardous for health at relatively low concentrations. They are also classified as human carcinogens according to EPA. Aldehydes are mainly formed from the oxidation of terpenes and from urea formaldehyde (UF) adhesives that are mainly present as adhesives in the flooring materials. In this paper I shall also review the standards that are used to approve such flooring products and the mechanisms behind the emission of aldehydes from UF adhesives. Our studies show that the levels of primary emissions are relatively high in such flooring materials and varies depending on if it is a parquet or laminate. These emissions may influence the indoor air quality and thereby may cause serious health problems. We have found that even an eco-labeled flooring material showed relatively high emission levels. This study reveals further that the standard used for the certification of building materials is not relevant to IAQ because they do not measure the total amount of free volatiles present in the flooring materials. The study reveals that to assure IAQ it is extremely important that the building materials are analyzed and specially when it concerns wooden materials.

Bron: https://doi.org/10.26434/chemrxiv-2022-116hx

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Finishing, or screeding, the hot mix asphalt or rapid-setting concrete surface of a crater repair is important for rapid airfield damage recovery (RADR) since it determines the aircraft ride surface quality. The objective of RADR repairs is to expediently produce a flush repair, defined as ±0.75 in. of the surrounding pavement surface, with minimal logistical and personnel burden. Multiple screeds were previously evaluated; the most recent project proposed a prototype design of a telehandler-operated integrated screed for both small and large repairs using asphalt or concrete. This project’s objective was to finalize the prototype design and fabricate and test the prototype RADR screed. The prototype RADR screed was successful for small repairs (8.5×8.5 ft). Large repairs (30×30 ft) were generally successful with modest repair quality criteria (RQC) issues being the only notable deficiencies. Large concrete repair RQC issues were attributed to plastic formwork movement, and large asphalt repair RQC issues were attributed to compaction issues or improper roll-down factors. Methods to mitigate these factors were investigated but should be further evaluated. Overall, the RADR screed was successful from technical perspectives but, functionally, is 600-800 lb overweight. Weight reduction should be considered before entering production.

Bron: https://doi.org/10.21079/11681/45406

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Floor screed with different amount of pozzolanic admixture was studied. There were designed 3 mixtures with different amount of the pozzolana. The basic physical properties, mechanical properties and frost resistance were determined. The water /cement coefficient was decided to be taken according to the consistence of the mortar. The mixtures were designed with respect to their application as screed. The properties of developed low-cost pozzolanic screed exceeds the reference material.

Bron: https://doi.org/10.4028/www.scientific.net/msf.824.77

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Nowadays, there is a tendency to use as much of waste products as possible to produce building materials. Every waste product used eliminates the inconvenience associated with the waste disposal process. Consequently, the waste recovery process becomes not only ecological but also economical. Many waste materials, which have not been sufficiently used so far, could very well substitute materials that would otherwise have to be elaborately prepared.

Bron: https://doi.org/10.4028/www.scientific.net/amr.1100.166

Onderzoeksrecord VV-0057 — Wat maakt een vloer glad? Een experimentele studie naar de slipweerstand van keramische tegels

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