Submit to Materials Review for Materials Propose a Special Issue

Journal Menu

Journal Browser

Environmentally Friendly Materials in Construction

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Benefits of Publishing in a Special Issue
Published Papers

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Construction and Building Materials".

Deadline for manuscript submissions: closed (20 March 2022) | Viewed by 40312

Share This Special Issue

Special Issue Editors

Prof. Dr. Nadezda Stevulova

E-Mail Website
Guest Editor

Institute of Environmental Engineering, Faculty of Civil Engineering, Technical University of Kosice, Vysokoskolska 4, 042 00 Kosice, Slovakia
Interests: sustainable building materials; hemp hurds utilization in new lightweight composites; waste materials utilization in cement and concrete production; particle matter/powder characterization
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Adriana Estokova

E-Mail Website
Guest Editor

Institute for Sustainable and Circular Construction, Faculty of Civil Engineering, Technical University of Kosice, Košice, Slovakia
Interests: heavy metals’ leachability from concrete; durability of materials; environmental evaluation of materials; environmental chemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Older buildings consume an excessive amount of energy and produce too much waste. Their operation is also linked with the consumption of about 25 percent of the world’s water and 40 percent of its resources, while creating one-third of all waste and 40 percent of global carbon emissions. Despite these statistics related to buildings’ unsustainability, buildings have a huge untapped potential to become a key part of the solution to urgent sustainability challenges. One of the important ways to improve the sustainability of buildings is to produce environmentally friendly materials and to design new eco-friendly building constructions. New eco-friendly designs of buildings based on the construction of environmentally friendly materials can improve human health, safety, comfort, and productivity in the current conditions of climate change. Environmentally friendly materials must become part of a sustainable world building design because their production and use could provide minimization of the negative environmental impacts. These impacts are representing by climate change, ozone layer depletion, acidification of soil and water, resource exhaustion or human toxicity in connection to indoor and outdoor air pollution. Therefore, it is very important to include sustainability ideas into products, operations, and research and development in order to apply the best available technologies and produce materials/products leaving a smaller negative environmental footprint in the process. Life cycle analysis (LCA) offers a useful and widely accepted methodology for assessment of ecofriendly sustainability and environmental performance of buildings. We invite you to submit high-quality research or review papers to this Special Issue, with an emphasis on new environmentally friendly building materials (concrete, mortars, plasters, bricks, insulating, and hybrid materials) and technologies. Some areas of interests for this Special Issue include but are not limited to environmental benefits of composites incorporating alternative substances and fiber-reinforced biocomposites. Papers aimed at environmentally acceptable composition of materials in construction, designing environmentally friendly construction buildings and environmental assessment of building materials, constructions, and buildings will be welcome. Papers will be accepted for this Special Issue after going through a rigorous peer-review procedure.

Prof. Dr. Nadezda Stevulova
Prof. Dr. Adriana Estokova
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

building materials with a low carbon footprint
environmentally safe building materials
low energy building materials
low-emitting building materials
new environmentally friendly technologies
composites with incorporated alternative substances
recycled and waste-incorporated building materials
optimization design of environmentally friendly construction
advanced building strategies in creating environmentally friendly structures
environmental assessment of building materials, structures, and buildings

Benefits of Publishing in a Special Issue

Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (14 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

13 pages, 4076 KiB

Open AccessArticle

Enhancement of Confinement in Scaled RC Columns using Steel Fibers Extracted from Scrap Tyres

by Izaz Ahmad, Mudasir Iqbal, Asim Abbas, Yasir Irfan Badrashi, Arshad Jamal, Shahid Ullah, Ahmed M. Yosri and Moustafa Hamad

Materials 2022, 15(9), 3219; https://doi.org/10.3390/ma15093219 - 29 Apr 2022

Cited by 10 | Viewed by 1856

Abstract

Steel fibers are widely extracted from scrap tyres, causing environmental concerns. This paper presents the use of steel fibers in variable proportions extracted from scrap tyres. The enhancement of the confinement was envisaged through the addition of steel fibers obtained from scrap tyres. The study included an experimental program for the development of constitutive material models for ordinary Portland cement (OPC) concrete and concrete with added steel fibers. A mix design was carried out for OPC, targeting a compressive strength of 3000 psi. Steel fibers were added to OPC in ratios of 1.0% to 3.0%, with an increment of 0.5%. Concrete columns, with cross-sectional dimensions of 6 × 6 inches and a length of 30 inches, were cast with both OPC and fiber-reinforced concrete. The column confinement was evaluated with a different spacing of ties (3- and 4-inch center-to-center). Compression tests on the concrete columns indicate that the addition of steel fibers to a concrete matrix results in an appreciable increase in strength and ductility. Overall, increasing the percentage of steel fibers increased the compression strength and the ductility of concrete. The maximum strain in the concrete containing 2.5% steel fibers increased by 285% as compared to the concrete containing 1% of steel fibers. An optimum percentage of 2.5% steel fibers added to the concrete resulted in a 39% increase in compressive strength, accompanied by a significant improvement in ductility. The optimum content of steel fibers, when used in confined columns, showed that confined compression strength increased with the addition of steel fibers. However, it is recommended that additional columns on the basis of the optimum steel fiber content shall be tested to evaluate their effectiveness in reducing the stirrup spacing. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

16 pages, 5804 KiB

Open AccessArticle

Degradation of Tetracycline on SiO₂-TiO₂-C Aerogel Photocatalysts under Visible Light

by Jian Wei, Pinghua Zhu and Peixin Chen

Materials 2022, 15(5), 1963; https://doi.org/10.3390/ma15051963 - 7 Mar 2022

Cited by 6 | Viewed by 2740

Abstract

SiO₂-TiO₂-C aerogel photocatalysts with different carbon loadings were synthesized by using sol-gel chemistry. The anatase crystal and nonmetal carbon dopant were introduced during the sol preparation and formed by hydrothermal treatment, which can simultaneously enhance the adsorption ability and visible light photo-activity. A high surface area (759 g cm⁻³) SiO₂-TiO₂-C aerogel composite can remove up to 80% tetracycline hydrochloride within 180 min under visible light. The characterization of the gel structures shows that the homogeneous dispersion of O, Si, Ti and C in the skeleton, indicating that hydrothermal synthesis could provide a very feasible way for the preparation of composite materials. n(C):n(Ti) molar ratio of 3.5 gives the best catalytic performance of the hybrid aerogel, and the cyclic test still confirms over 60% degradation activity after seven use cycles. All catalysis reaction followed the pseudo-first-order rate reaction with high correlation coefficient. The electrons and holes in the compound could be effectively restrained with doping proper amount of C, and ESR results indicate that the oxidation process was dominated by the hydroxyl radical (•OH) and superoxide radical (•O₂⁻) generated in the system. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

14 pages, 46759 KiB

Open AccessArticle

An Effective Expanded Graphite Coating on Polystyrene Bead for Improving Flame Retardancy

by Minjung Bae, Hyunhwa Lee, Gyeongseok Choi and Jaesik Kang

Materials 2021, 14(21), 6729; https://doi.org/10.3390/ma14216729 - 8 Nov 2021

Cited by 2 | Viewed by 2855

Abstract

Although foamed plastic insulation is widely used in construction in the Korean market, it is vulnerable to fire. To improve the flame retardancy, the method of flame-retardant coating with the EG in water-soluble state on the surface of expanded polystyrene (EPS) beads has been widely used. However, polystyrene beads coated with a water-soluble flame retardant easily separate the coated flame retardant in manufacturing. In this study is devised a flame-retardant coating and two steps of coating process for adhering the flame-retardant coating film evenly to the surface of the polystyrene bead without exfoliation. It was analyzed whether a flame-retardant EPS (FR-EPS) with excellent flame retardancy could be manufactured using polystyrene beads coated in this way. Ten FR-EPS samples satisfied the HF-1 and V-0 levels in horizontal and vertical burning tests, respectively. The THR of eight FR-EPS samples for ten minutes did not exceed 8 MJ∙m⁻² and the maximum HRR did not exceed 200 kW∙m⁻² for more than ten consecutive seconds. FR-EPS passed the building material standard of semi-nonflammability in Korean regulations, in contrast to commercial EPS, which have not passed the semi-nonflammability standard. It was also analyzed how effective the designed coating is in this study, comparing it with composites that were planned to improve the flame resistance of polystyrene, as reported in the literature. Flame Retardancy Index (FRI) values of FR-EPS proved the “excellent” level and had higher values compared with other polystyrene composites. These results demonstrated that the coated EPS containing a water-soluble flame retardant manufactured from EG and two steps of application with the coating solution achieved fire safety standard regulations. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

17 pages, 7482 KiB

Open AccessArticle

Renovation Effect of Flax FRP-Reinforced Cracked Concrete Slabs under Impact Loadings

by Wenjie Wang, Zonglai Mo, Nawawi Chouw and Krishnan Jayaraman

Materials 2021, 14(20), 6212; https://doi.org/10.3390/ma14206212 - 19 Oct 2021

Cited by 5 | Viewed by 1986

Abstract

The impact behaviour of flax fibre-reinforced polymer (FFRP) renovated coconut fibre-reinforced concrete (CFRC) slabs was investigated through two series of experiments and theoretical analysis. The first experiment was carried out to find out the effectiveness of FFRP retrofitted method for the partly damaged concrete structure and its performance under impact loadings. The renovation process was applied on the pre-cracked rectangular CFRC slabs of 600 mm × 300 mm × 50 mm with FFRP laminates, before the repeated impact tests. Then, the parameters of these slabs, i.e., impact force history, deflection history and damage pattern, were discussed in detail. Another experiment was conducted on the FFRP-CFRC square slabs with a dimension of 600 mm × 600 mm × 50 mm. Based on test results, the effect of different FFRP configurations was discussed to find out the effective reinforcement method. In addition, the two-degree-of-freedom spring-mass model was applied to predict the impact force. Results demonstrate that FFRP composites have a good potential to be utilised as renovated construction materials under dynamic load conditions. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

22 pages, 37105 KiB

Open AccessArticle

Effects of a Real Exposure Class XC4 Mediterranean Climate Environment in the Behavior of Mortars Made Using Ternary Binders with Addition of Slag, Fly Ash and Limestone

by Javier Ibáñez-Gosálvez, Teresa Real-Herraiz and José Marcos Ortega

Materials 2021, 14(19), 5848; https://doi.org/10.3390/ma14195848 - 6 Oct 2021

Viewed by 1411

Abstract

For improving the contribution of the cement industry to mitigate global warming, many strategies have been put into practice, such as the use of eco-friendly cements with the incorporation of additions substituting clinker. Nevertheless, the use of ternary binders for the production of commercial cements is still reduced, particularly in Spain. The purpose of this research is to characterize the long-term influence produced by the exposure to a real in situ inland Mediterranean climate condition in the pore network, parameters related to durability and mechanical performance of mortars made with ternary binders, which incorporated limestone, fly ash, and ground granulated blast-furnace slag, in comparison with mortars without additions and binary blended mortars. The site verified the specifications of exposure class XC4 of Eurocode 2. The ternary and binary binders accomplished the prescriptions of cement type CEM II/B. The pore network was studied with mercury intrusion porosimetry and electrical resistivity. Water absorption, diffusion coefficient, carbonation depth, ultrasonic pulse velocity, compressive and flexural strengths have been determined. The exposure to the environment produced after 250 days an increase in porosity, a loss of pore refinement, a rise of the carbonation depths, and a reduction in the mechanical strengths, highlighting the better overall performance of ternary mortar with both fly ash and slag. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

18 pages, 3715 KiB

Open AccessArticle

Durability Assessment and Microstructure of High-Strength Performance Bricks Produced from PET Waste and Foundry Sand

by Frank Ikechukwu Aneke, Bankole Osita Awuzie, Mohamed M. H. Mostafa and Chikezirim Okorafor

Materials 2021, 14(19), 5635; https://doi.org/10.3390/ma14195635 - 28 Sep 2021

Cited by 21 | Viewed by 3423

Abstract

Fired clay brickwork in buildings is prone to cracks and deterioration upon exposure to long-time acidic contamination and water absorption, hence decreasing the bearing capacity of masonry walls. As its contribution toward resolving this challenge, this study assessed the durability and morphological characteristics of high-strength performance bricks produced from a mixture of PET waste (PW) and foundry sand (FS). The PET waste bricks (PWBs) were produced through different proportioning (PW: FS) of 20%, 30%, and 40% of the dry mass of FS. The PWBs produced were tested for durability and compressive and tensile strengths and compared to fired clay bricks to evaluate their load-bearing capacity under compression and tension. Furthermore, scanning electron microscopy (SEM) tests were employed to analyze the morphological structure of the bricks. The test results revealed that the PWBs recorded an appreciable strength of 1.5–2 times that of fired clay bricks, and lower water absorption whilst retaining their ultimate strengths after complete immersion in water and acidic concentrations. The morphology of PWB possessed greater intercluster bonds on the surface compared to clay bricks. The findings demonstrate a reasonable methodological approach toward the production of masonry bricks using a mixture of PET waste and spent foundry sands. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

23 pages, 10579 KiB

Open AccessArticle

Heat Transfer in Straw-Based Thermal Insulating Materials

by Dániel Csanády, Olivér Fenyvesi and Balázs Nagy

Materials 2021, 14(16), 4408; https://doi.org/10.3390/ma14164408 - 6 Aug 2021

Cited by 16 | Viewed by 3242

Abstract

An analytic-empirical model was developed to describe the heat transfer process in raw straw bulks based on laboratory experiments for calculating the thermal performance of straw-based walls and thermal insulations. During the tests, two different types of straw were investigated. The first was barley, which we used to compose our model and identify the influencing model parameters, and the second was wheat straw, which was used only for validation. Both straws were tested in their raw, natural bulks without any modification except drying. We tested the thermal conductivity of the materials in a bulk density range between 80 and 180 kg/m³ as well as the stem density, material density, cellulose content, and porosity. The proposed model considers the raw straw stems as natural composites that contain different solids and gas phases that are connected in parallel to each other. We identified and separated the following thermal conductivity factors: solid conduction, gas conduction in stem bulks with conduction factors for pore gas, void gas, and gaps among stems, as well as radiation. These factors are affected by the type of straw and their bulk density. Therefore, we introduced empirical flatness and reverse flatness factors to our model, describing the relationship between heat conduction in stems and voids to bulk density using the geometric parameters of undisturbed and compressed stems. After the validation, our model achieved good agreement with the measured thermal conductivities. As an additional outcome of our research, the optimal bulk densities of two different straw types were found to be similar at 120 kg/m³. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

12 pages, 8551 KiB

Open AccessArticle

Analysis of the Fire Properties of Blown Insulation from Crushed Straw in the Buildings

by Jiří Teslík

Materials 2021, 14(15), 4336; https://doi.org/10.3390/ma14154336 - 3 Aug 2021

Cited by 9 | Viewed by 2957

Abstract

Sustainable development in civil engineering is the clear and necessary goal of the current generation. There are many possibilities for reducing the use of depletable resources. One of them is to use renewable and recyclable materials on a larger scale in the construction industry. One possibility is the application of natural thermal insulators. A typical example is a crushed straw, which is generated as agricultural waste in the Czech Republic. Due to its small dimensions and good thermal insulation parameters, this material can also be used as blown thermal insulation. The research aims to examine the fire resistance of crushed straw as blown insulation. The single-flame source fire test results, thermal attack by a single burning item (SBI) test and large-scale test of a perimeter wall segment are shown. The results show that blown insulation made of crushed straw meets the requirements of fire protection. In addition, crushed straw can be also used to protect load-bearing structures due to its behaviour. This article also shows the production process of crushed straw used as blown insulation in brief. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

16 pages, 4733 KiB

Open AccessArticle

Time-Dependent Response of a Recycled C&D Material-Geotextile Interface under Direct Shear Mode

by Fernanda Bessa Ferreira, Paulo M. Pereira, Castorina Silva Vieira and Maria de Lurdes Lopes

Materials 2021, 14(11), 3070; https://doi.org/10.3390/ma14113070 - 4 Jun 2021

Cited by 9 | Viewed by 2248

Abstract

Geosynthetic-reinforced soil structures have been used extensively in recent decades due to their significant advantages over more conventional earth retaining structures, including the cost-effectiveness, reduced construction time, and possibility of using locally-available lower quality soils and/or waste materials, such as recycled construction and demolition (C&D) wastes. The time-dependent shear behaviour at the interfaces between the geosynthetic and the backfill is an important factor affecting the overall long-term performance of such structures, and thereby should be properly understood. In this study, an innovative multistage direct shear test procedure is introduced to characterise the time-dependent response of the interface between a high-strength geotextile and a recycled C&D material. After a prescribed shear displacement is reached, the shear box is kept stationary for a specific period of time, after which the test proceeds again, at a constant displacement rate, until the peak and large-displacement shear strengths are mobilised. The shear stress-shear displacement curves from the proposed multistage tests exhibited a progressive decrease in shear stress with time (stress relaxation) during the period in which the shear box was restrained from any movement, which was more pronounced under lower normal stress values. Regardless of the prior interface shear displacement and duration of the stress relaxation stage, the peak and residual shear strength parameters of the C&D material-geotextile interface remained similar to those obtained from the conventional (benchmark) tests carried out under constant displacement rate. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

15 pages, 2822 KiB

Open AccessArticle

Life Cycle Impact Assessment of Load-Bearing Straw Bale Residential Building

by Rozalia Vanova, Michal Vlcko and Jozef Stefko

Materials 2021, 14(11), 3064; https://doi.org/10.3390/ma14113064 - 4 Jun 2021

Cited by 17 | Viewed by 3709

Abstract

As a renewable raw material, straw bale represents a sustainable way of construction with minimal environmental impact. This paper focused on life cycle impact assessment of load-bearing straw bale residential building. Product stage from raw materials extraction to manufacture of construction materials was considered in the assessment including seven variations of straw bale. Construction materials were evaluated due to IMPACT 2002+ method. Both midpoint and endpoint impact categories were included. The results showed the importance of straw bale origin. Ecosystem quality impact of straw from extensively cultivated pastures was twenty times higher than that of intensive crop production, thus making a significant difference to an overall score of the construction. Results showed advantage of straw as a construction material particularly when used locally. In addition, significant contributions of other construction materials were identified. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

31 pages, 8503 KiB

Open AccessEditor’s ChoiceArticle

Concept of Evaluation of Mineral Additives’ Effect on Cement Pastes’ Durability and Environmental Suitability

by Robert Figmig, Adriana Estokova and Miloslav Luptak

Materials 2021, 14(6), 1448; https://doi.org/10.3390/ma14061448 - 16 Mar 2021

Cited by 6 | Viewed by 2582

Abstract

This experimental study focuses on the assessment of mineral additives and their incorporation into cement composites (CC). The assessment was based on a holistic approach to the performance of the durability properties of CC. Environmental suitability was also taken into consideration. In the experiments, cement pastes with w/c ratios of 0.3, 0.4, and 0.5, respectively, were prepared. Natural zeolite (NZ) and densified silica fume (SF) at doses of 7.5 and 15.0 wt.% of cement were used as the investigated (replacement) materials. Their effects (including development over time) on density, strength (flexural and compressive), porosity by water absorption, permeability by rapid chloride penetration (RCP) test, phase content by thermal analysis, and hydration progression, were observed. The results were then used to propose an evaluation approach. Natural zeolite was used for its known pozzolanic activity and classification as a supplementary cementitious material (SCM). In contrast SF acted as a filler in cement pastes, and thus did not have a direct positive effect on durability. The concept of comprehensive analysis for unknown additive classification is proposed to expressly differentiate between SCM, inert, and improving mineral additive. This concept could be applied to the assessment of mineral additives with regards to the durability and suitability of cement composites. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

16 pages, 6530 KiB

Open AccessArticle

Coir Fibers Treated with Henna as a Potential Reinforcing Filler in the Synthesis of Polyurethane Composites

by Sylwia Członka, Anna Strąkowska and Agnė Kairytė

Materials 2021, 14(5), 1128; https://doi.org/10.3390/ma14051128 - 27 Feb 2021

Cited by 16 | Viewed by 3038

Abstract

In this study, coir fibers were successfully modified with henna (derived from the Lawsonia inermis plant) using a high-energy ball-milling process. In the next step, such developed filler was used as a reinforcing filler in the production of rigid polyurethane (PUR) foams. The impact of 1, 2, and 5 wt % of coir-fiber filler on structural and physico-mechanical properties was evaluated. Among all modified series of PUR composites, the greatest improvement in physico-mechanical performances was observed for PUR composites reinforced with 1 wt % of the coir-fiber filler. For example, on the addition of 1 wt % of coir-fiber filler, the compression strength was improved by 23%, while the flexural strength increased by 9%. Similar dependence was observed in the case of dynamic-mechanical properties—on the addition of 1 wt % of the filler, the value of glass transition temperature increased from 149 °C to 178 °C, while the value of storage modulus increased by ~80%. It was found that PUR composites reinforced with coir-fiber filler were characterized by better mechanical performances after the UV-aging. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

16 pages, 3032 KiB

Open AccessArticle

Ecotoxicity and Essential Properties of Fine-Recycled Aggregate

by Diana Mariaková, Klára Anna Mocová, Kristina Fořtová, Pavla Ryparová, Jan Pešta and Tereza Pavlů

Materials 2021, 14(2), 463; https://doi.org/10.3390/ma14020463 - 19 Jan 2021

Cited by 11 | Viewed by 2543

Abstract

This article deals with the possibility of utilization of secondary-raw materials as a natural sand replacement in concrete. Four types of waste construction materials were examined—recycled aggregate from four different sources. The natural aggregate was examined as well as used as the reference sample. All the samples were tested to evaluate the water absorption, particle size distribution, and particle density. The basic chemical reactions in the view of ecotoxicology are investigated and measured based on Czech standards. Chemical analysis, Lemna growth inhibition test, freshwater algae, daphnia acute, and mustard germination toxicity test were made and discussed in this paper. Based on the physical and geometrical properties and ecotoxicology of examined waste materials, this work evaluated them as suitable for utilization in concrete as a sand replacement. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Figure 1

17 pages, 6348 KiB

Open AccessEditor’s ChoiceArticle

Development and Characterization of “Green Open-Cell Polyurethane Foams” with Reduced Flammability

by Maria Kurańska, Hynek Beneš, Kamila Sałasińska, Aleksander Prociak, Elżbieta Malewska and Krzysztof Polaczek

Materials 2020, 13(23), 5459; https://doi.org/10.3390/ma13235459 - 30 Nov 2020

Cited by 19 | Viewed by 2787

Abstract

This work presents the cell structure and selected properties of polyurethane (PUR) foams, based on two types of hydroxylated used cooking oil and additionally modified with three different flame retardants. Bio-polyols from municipal waste oil with different chemical structures were obtained by transesterification with triethanolamine (UCO_TEA) and diethylene glycol (UCO_DEG). Next, these bio-polyols were used to prepare open-cell polyurethane foams of very low apparent densities for thermal insulation applications. In order to obtain foams with reduced flammability, the PUR systems were modified with different amounts (10–30 parts per hundred polyol by weight—php) of flame retardants: TCPP (tris(1-chloro-2-propyl)phosphate), TEP (triethyl phosphate), and DMPP (dimethyl propylphosphonate). The flame retardants caused a decrease of the PUR formulations reactivity. The apparent densities of all the foams were comparable in the range 12–15 kg/m³. The lowest coefficients of thermal conductivity were measured for the open-cell PUR foams modified with DMPP. The lowest values of heat release rate were found for the foams based on the UCO_TEA and UCO_DEG bio-polyols that were modified with 30 php of DMPP. Full article

(This article belongs to the Special Issue Environmentally Friendly Materials in Construction)

► Show Figures

Journal Menu

Journal Browser

Environmentally Friendly Materials in Construction

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (14 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI