scholarly journals Posuzování recyklovaného betonu z hlediska jeho dopadu na životní prostředí

Entecho ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 1-11
Author(s):  
Jan Pešta ◽  
Tereza Pavlů ◽  
Klára Anna Mocová ◽  
Vladimír Kočí
Keyword(s):  
Life Cycle Assessment ◽  
Environmental Impacts ◽  
Assessment Method ◽  
Analytical Tool ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Concrete Mixtures ◽  
Energy Consuming

Recyklací stavebního a demoličního odpadu jsou produkovány materiály, které mohou být využity jako náhrada primárních surovin. Tyto recyklační procesy ale mohou být energeticky náročné, a proto je nutné posuzovat environmentální dopady takových procesů. Posuzovali jsme environmentální dopady recyklovaného betonového a cihelného kameniva a také environmentální dopady produktů s recyklovaným obsahem. Metoda Posuzování životního cyklu byla použita jako analytický nástroj pro vyhodnocení environmentálních dopadů recyklovaných materiálů (1 t betonového a cihelného kameniva), výrobků (1 m3 betonových směsí s obsahem recyklátu) a konstrukcí (tvarovek a základů budov). Také byly diskutovány vlivy na životní prostředí jako je ekotoxicita betonových výrobků, následky omezení skládkování a karbonatace. Prezentujeme výsledky posuzování environmentálních dopadů s cílem ukázat, jaký dopad má vybraná funkce recyklovaného produktu. Navrhujeme posuzovat environmentální dopady recyklovaného kameniva s ohledem na jeho použití v budoucnu. ------------- Recycling of construction and demolition waste produce materials, which can be used as primary resources replacement. However, these recycling processes can be very energy consuming and therefore environmental impacts of such processes should be considered. We assessed environmental impacts of recycled concrete and brick aggregates and also environmental impacts of products with recycled content. The Life Cycle Assessment method was used as analytical tool for evaluating environmental impacts of recycled materials (1 t of concrete or brick aggregates), products (1 m3 recycled concrete mixtures) and constructions (blocks and building foundations). Also, various effects on environment were discussed such as ecotoxicity of concrete products, the consequence of landfilling limitations and carbonation effect. We present the results of environmental impacts assessments to show, what influence the chosen function of recycled product has. We suggest to assess environmental impacts of recycled aggregates considering their future function.

scholarly journals From Buildings’ End of Life to Aggregate Recycling under a Circular Economic Perspective: A Comparative Life Cycle Assessment Case Study

2021 ◽  
Vol 13 (17) ◽  
pp. 9625
Author(s):  
Ambroise Lachat ◽  
Konstantinos Mantalovas ◽  
Tiffany Desbois ◽  
Oumaya Yazoghli-Marzouk ◽  
Anne-Sophie Colas ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
End Of Life ◽  
Environmental Impacts ◽  
Open Loop ◽  
Decision Makers ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste

The demolition of buildings, apart from being energy intensive and disruptive, inevitably produces construction and demolition waste (C&Dw). Unfortunately, even today, the majority of this waste ends up underexploited and not considered as valuable resources to be re-circulated into a closed/open loop process under the umbrella of circular economy (CE). Considering the amount of virgin aggregates needed in civil engineering applications, C&Dw can act as sustainable catalyst towards the preservation of natural resources and the shift towards a CE. This study completes current research by presenting a life cycle inventory compilation and life cycle assessment case study of two buildings in France. The quantification of the end-of-life environmental impacts of the two buildings and subsequently the environmental impacts of recycled aggregates production from C&Dw was realized using the framework of life cycle assessment (LCA). The results indicate that the transport of waste, its treatment, and especially asbestos’ treatment are the most impactful phases. For example, in the case study of the first building, transport and treatment of waste reached 35% of the total impact for global warming. Careful, proactive, and strategic treatment, geolocation, and transport planning is recommended for the involved stakeholders and decision makers in order to ensure minimal sustainability implications during the implementation of CE approaches for C&Dw.

scholarly journals VERIFICATION OF THE BASIC PROPERTIES OF RECYCLED AND NATURAL AGGREGATES

2019 ◽  
Vol 22 ◽  
pp. 67-71
Author(s):  
Karel Mikulica ◽  
Iveta Hájková
Keyword(s):  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Building Structures ◽  
Recycled Concrete Aggregate ◽  
Apartment Building ◽  
Demolition Waste ◽  
Concrete Mixtures ◽  
Natural Aggregates

In the future, it is planned to use up to 50% of construction and demolition waste (C&DW) for the production of new building structures. This leads us to think about how we can use recycled concrete aggregate (RCA) as a substitute for natural aggregate (NA) in concrete mixtures. This is why we compare the two typical representatives of recycled aggregates with a representative of natural aggregates. As a representative of recycled aggregates, we chose pure concrete recycled from the cutting of concrete and mixed recyclate from the demolition of the apartment building. As a representative of natural stone, we chose the extracted aggregate.

scholarly journals Comparative study of the influence of three types of fibre in the shrinkage of recycled mortar

2018 ◽  
Vol 68 (332) ◽  
pp. 168 ◽  
Author(s):  
P. Saiz-Martínez ◽  
D. Ferrández-Vega ◽  
C. Morón-Fernández ◽  
A. Payán de Tejada-Alonso
Keyword(s):  
Negative Impact ◽  
Polypropylene Fiber ◽  
Capacitive Sensor ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Moisture Loss ◽  
Recycled Aggregates ◽  
Fiber Types ◽  
Demolition Waste ◽  
Recycled Concrete Aggregates

Construction and demolition waste can be used as a substitution of natural aggregate in mortar and concrete elaboration. A poorer quality of recycled aggregates generally has negative impact on mortar properties. Shrinkage is one of the properties that experiences worse outcome due to the higher absorption of recycled aggregates. This research evaluates the potential shrinkage of mortars elaborated with recycled concrete aggregates both with and without fibres addition, as well as the relation between moisture loss and shrinkage caused by mortar drying process using a capacitive sensor of the authors’ own design. Two different mortar dosages 1:3 and 1:4 and three fiber types: polypropylene fiber, fiberglass and steel fiber, in different proportions were used. Obtained results show that the use of polypropylene fiber improves the recycled mortars performance against shrinkage in 0.2%. Moreover, a clear relation between dry shrinkage and moisture loss was observed.

scholarly journals Laboratory Evaluation of Hot Asphalt Concrete Properties with Cuban Recycled Concrete Aggregates

2018 ◽  
Vol 10 (8) ◽  
pp. 2590 ◽  
Author(s):  
Debora Acosta Alvarez ◽  
Anadelys Alonso Aenlle ◽  
Antonio Tenza-Abril
Keyword(s):  
Asphalt Concrete ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Laboratory Evaluation ◽  
Maximum Aggregate Size ◽  
Demolition Waste ◽  
Aggregate Fraction

Recycled Aggregates (RA) from construction and demolition waste (CDW) are a technically viable alternative to manufacture of asphalt concrete (AC). The main objective of this work is to evaluate the properties of hot asphalt mixtures that have been manufactured with different sources of CDW (material from concrete test specimens, material from the demolition of sidewalks and waste from prefabrication plants) from Cuba. Dense asphalt mixtures were manufactured with a maximum aggregate size of 19 mm, partially replacing (40%) the natural aggregate fraction measured between 5 mm and 10 mm with three types of RA from Cuba. Marshall specimens were manufactured to determine the main properties of the AC in terms of density, voids, stability and deformation. Additionally, the stiffness modulus of the AC was evaluated at 7 °C, 25 °C and 50 °C. The results corroborate the potential for using these sources of CDW from Cuba as a RA in asphalt concrete, thereby contributing an important environmental and economic benefit.

scholarly journals Complete Real-Scale Application of Recycled Aggregates in a Port Loading Platform in Huelva, Spain

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2651
Author(s):  
Francisco Agrela ◽  
Francisco González-Gallardo ◽  
Julia Rosales ◽  
Javier Tavira ◽  
Jesús Ayuso ◽  
...  
Keyword(s):  
Civil Engineering ◽  
Recycled Concrete ◽  
Environmental Benefits ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Base Layer ◽  
Recycling Rate ◽  
Demolition Waste ◽  
Technical Requirements ◽  
Real Scale

The application of recycled aggregates (RA) from construction and demolition waste and crushed concrete blocks is a very important challenge for the coming years from the environmental point of view, in order to reduce the exploitation of natural resources. In Spain, the use of these recycled materials in the construction of road bases and sub-bases is growing significantly. However, presently, there are few studies focused on the properties and behavior of RA in civil works such as road sections or seaport platforms. In this work, two types of RA were studied and used in a complete real-scale application. Firstly, recycled concrete aggregates (RCA) were applied in the granular base layer under bituminous superficial layers, and secondly mixed recycled aggregates (MRA) which contain a mix of ceramic, asphalt, and concrete particles were applied in the granular subbase layer, under the base layer made with RCA. Both RA were applied in a port loading platform in Huelva, applying a 100% recycling rate. This civil engineering work complied with the technical requirements of the current Spanish legislation required for the use of conventional aggregates. The environmental benefits of this work have been very relevant, and it should encourage the application of MRA and RCA in civil engineering works such as port platforms in a much more extended way. This is the first and documented real-scale application of RA to completely build the base and sub-base of a platform in the Huelva Port, Spain, replacing 100% of natural aggregates with recycled ones.

Production of upgraded recycled aggregates from construction and demolition waste for replacement of primary sand in cement mortars

2020 ◽  
Author(s):  
Michael Galetakis ◽  
Athanasia Soultana ◽  
Theodoros Daskalakis
Keyword(s):  
Water Absorption ◽  
Cement Paste ◽  
Cement Mortar ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Cement Mortars ◽  
Limestone Sand ◽  
Crushed Limestone

<p>Waste concrete is the most predominant constituent material among construction and demolition waste. Recycling of this material could minimize landfilled waste and mineral resources depletion. This study investigates, in laboratory scale, the production of upgraded recycled concrete aggregates, suitable for the replacement of primary (crushed limestone sand) used in cement mortars, by means of selective crushing and autogenous grinding. These particle size reduction techniques, compared to traditional crushing/grinding, have the potential to remove the brittle cement paste from the aggregates, thus significantly improving their quality. The granulometry, the density, the water absorption (EN 13755) and the flow coefficient (EN 933-6) of the produced upgraded sand was determined and compared to crushed limestone sand. Subsequently, cement mortar specimens were manufactured using upgraded aggregates for total replacement of crushed limestone sand. Specimens were tested for their compressive and flexural strength (EN 196-1), density and water absorption. Results indicated that the upgraded recycled sand produced through the selective crushing and autogenous grinding processes had improved properties compared to the one produced by conventional crushing processes (flexural and compressive strength of cement mortar specimens were increased by 29% and 7%, respectively). However, the quality of the upgraded sand is lower than that of the primary crushed limestone. To further explore the issue, it is planned to investigate in more detail the process of autogenous grinding and to investigate the use of other selective aggregate-cement paste liberation technologies.</p>

scholarly journals Upgrading the Quality of Recycled Aggregates from Construction and Demolition Waste by Using a Novel Brick Separation and Surface Treatment Method

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2893
Author(s):  
Kui Hu ◽  
Yujing Chen ◽  
Caihua Yu ◽  
Dong Xu ◽  
Shihao Cao ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Precast Concrete ◽  
Highway Construction ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Base Layer ◽  
Quality Level ◽  
Demolition Waste ◽  
Shape Characteristics

Mixed recycled aggregates (MRA) from construction and demolition waste (CDW) with high-purity and environmental performance are required for highway construction application in base layer and precast concrete curbs. The main problematic constituents that reduce the quality level of the recycled aggregates applications are brick components, flaky particles, and attached mortar, which make up a large proportion of CDW in some countries. This paper studies the potential of brick separation technology based on shape characteristics in order to increase the recycled concrete aggregates (RCA) purity for MRA quality improvement. MRA after purification was also processed with surface treatment experiment by rotating in a cylinder to improve the shape characteristics and to remove the attached mortar. The purity, strength property, densities, water absorption ratio, shape index, and mortar removal ratio of MRA were studied before and after the use of the brick separation and surface treatment proposed in this study. Finally, the recycled aggregates upgradation solution was adopted in a stationary recycling plant designed for a length of 113 km highway construction. The properties of CDW mixed concrete for precast curbs manufacturing were conducted. The results indicate that problematic fractions (brick components, particle shape, and surface weakness) in the MRA were significantly reduced by using brick separation and surface treatment solution. Above all, it is very important that the proposed brick separation method was verified to be practically adopted in CDW recycling plant for highway base layer construction and concrete curbs manufacturing at a low cost.

scholarly journals Application of life cycle assessment (LCA) methodology and economic evaluation for construction and demolition waste: a Colombian case study

2021 ◽  
Vol 25 (3) ◽  
pp. 341-351
Author(s):  
Sindy Sofía Suárez Silgado ◽  
Lucrecia Janneth Calderon Valdiviezo ◽  
Leandro Fernando Mahecha Vanegas
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impacts ◽  
Raw Materials ◽  
Construction And Demolition Waste ◽  
Lca Methodology ◽  
Environmental Implications ◽  
Demolition Waste ◽  
Secondary Sources ◽  
Management Processes

The construction industry consumes more raw materials and energy than any other economic activity and generates the largest fraction of waste, known as construction and demolition waste (CDW). This waste has significant environmental implications, most notably in South American countries such as Colombia, where it is handled inappropriately. This study evaluated the management processes currently used for fractions of construction and demolition waste generated in Ibagué (Colombia). The environmental impacts of the management of 1 kg of CDW were also calculated. Other CDW management alternatives were evaluated. The percentage of the fraction of the waste and the treatment or management processes used were modified to determine its environmental and economic viability. The information was obtained through telephone interviews and visits to recycling plants, construction companies, quarries, government entities, and inert landfills. It was completed with secondary sources and the Ecoinvent v.2.2 databases. Life Cycle Assessment (LCA) methodology and the SimaPro 8 software were used to calculate the environmental impacts. An economic study of each management process and each alternative was also carried out. A comparison of the other options revealed the current choice contributes most to the environmental impacts in all categories. This study indicates that the most beneficial alternative in environmental and economic terms in Ibagué (Colombia) is where 100% of the metals are recovered, 100% of excavated earth is reused, and 100% of the stone waste is recycled (alternative 3). This alternative remained the most favorable when a sensitivity analysis was carried out with different distances (30 km and 50 km).

scholarly journals Development of Concrete Incorporating Recycled Aggregates, Hydrated Lime and Natural Volcanic Pozzolan

2021 ◽  
Vol 6 (11) ◽  
pp. 155
Author(s):  
Natividad Garcia-Troncoso ◽  
Bowen Xu ◽  
Wilhenn Probst-Pesantez
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Demolition Waste ◽  
Crushed Concrete ◽  
Natural Pozzolana ◽  
Concrete Materials

Recycling of construction and demolition waste is a central point of discussion throughout the world. The application of recycled concrete as partial replacement of mineral aggregates in concrete mixes is one of the alternatives in the reduction of pollution and savings in carbon emissions. The combined influence of the recycled crushed concrete, lime, and natural pozzolana on the mechanical and sustainable properties of concrete materials is firstly proposed in this study. In this research, unconventional construction materials are employed to produce concrete: the recycled crushed concrete is used as coarse aggregate, while lime and natural pozzolana are used as a partial replacement for cement. Substitutions of 10%, 20%, 50% of gravel are made with recycled aggregates, and 2%, 5%, 10% of cement with lime and natural pozzolan. Tests on the fresh and hardened properties, destructive (compressive strength) and non-destructive tests (sclerometer rebound and ultrasound) of mixtures are carried out. It is shown that the use of recycled materials can provide an increase in compressive strength of up to 34% with respect to conventional concrete. Life cycle cost and sustainability assessments indicate that concrete materials incorporating recycled aggregate possess good economic and environmental impacts.

scholarly journals Concrete-Based and Mixed Waste Aggregates in Rendering Mortars

2020 ◽  
Author(s):  
Cinthia Maia Pederneiras
Keyword(s):  
Mechanical Performance ◽  
Ceramic Materials ◽  
Cementitious Materials ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Demolition Waste ◽  
Recycled Concrete Aggregates ◽  
Mixed Recycled Aggregates

The construction industry is considered the biggest waste producer in Europe. In order to encourage recycling, European Parliament decreed through the Waste Framework Directive 2008/98/EC, that at least 70% of construction and demolition waste should be recycled by 2020. From recycling plants, three types of recycled aggregates are produced. Recycled Concrete Aggregate, mainly from cementitious waste, as such as concrete and mortars residues; Recycled Masonry Aggregates mainly composed by recycled ceramic materials, as such as tiles and bricks residues; Mixed Recycled Aggregates based on rubble residues, from heterogenous materials waste. This research evaluated the technical feasibility of rendering mortars with Recycled Concrete Aggregates and Mixed Recycled Aggregates, in different volume incorporation of 0%, 20%, 50% and 100%. The experimental programme comprised an analyse of the fresh and hardened properties, regarding the water and mechanical behaviour of the mortars. From the results, it was noticed that the modified mortars presented a reduction in the modulus of elasticity, which its correlated to a less susceptibility to cracking. Regarding mechanical performance, the modified mortars obtained reduction of the flexural and compressive strength over time. However, it was not a significant harmful criterion. Therefore, the incorporation of recycled aggregates in cementitious materials is considered a technical and sustainable solution.

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