scholarly journals A Critical Review on the Influence of Fine Recycled Aggregates on Technical Performance, Environmental Impact and Cost of Concrete

2020 ◽  
Vol 10 (3) ◽  
pp. 1018 ◽  
Author(s):  
Hisham Hafez ◽  
Reben Kurda ◽  
Rawaz Kurda ◽  
Botan Al-Hadad ◽  
Rasheed Mustafa ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Critical Review ◽  
Economic Life ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Extensive Literature ◽  
Demolition Waste ◽  
Technical Performance ◽  
Fine Aggregates ◽  
Natural Aggregates

The aim of this critical review is to show the applicability of recycled fine aggregates (RFA) in concrete regarding technical performance, environmental impact, energy consumption and cost. It is not possible to judge the performance of concrete by considering one dimension. Thus, this study focussed on the fresh and hardened (e.g., mechanical and durability) properties and environmental and economic life cycle assessment of concrete. Most literature investigated showed that any addition of recycled fine aggregates from construction and demolition waste as a replacement for natural fine aggregates proves detrimental to the functional properties (quality) of the resulting concrete. However, the incorporation of recycled fine aggregates in concrete was proven to enhance the environmental and economic performance. In this study, an extensive literature review based multi criteria decision making analysis framework was made to evaluate the effect of RFA on functional, environmental, and economic parameters of concrete. The results show that sustainability of RFA based concrete is very sensitive to transportation distances. Several scenarios for the transportation distances of natural and recycled fine aggregates and their results show that only if the transportation distance of the natural aggregates is more than double that of RFA, e the RFA based concrete alternatives would be considered as more sustainable.

scholarly journals Environmental and Economic Life Cycle Assessment of Recycled Coarse Aggregates: A Portuguese Case Study

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5452
Author(s):  
Adriana B. Dias ◽  
João N. Pacheco ◽  
José D. Silvestre ◽  
Isabel M. Martins ◽  
Jorge de Brito
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impact ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Coarse Aggregates ◽  
Natural Aggregates ◽  
Ready Mix Concrete

The incorporation of recycled aggregates in concrete not only reduces the extraction of natural resources, but also decreases landfill disposal of construction and demolition waste. Hence, environmental impacts and costs are reduced, promoting the use of recycled aggregates and circular economy. However, the impacts of transport depend on the distance between facilities and longer distances may result in recycled aggregates being more costly and having larger environmental impact than natural aggregates. This paper discusses this topic, presents a review on the use of life cycle assessment methodology on natural and recycled aggregates for concrete, and applies this methodology in a real context pertaining the procurement of coarse aggregates to ready-mix concrete plants. A case study of two Portuguese regions, Coimbra and Lisbon, is presented. For each region, a quarry, a construction and demolition waste plant, and a ready-mix concrete plant are chosen and a comparative life cycle assessment is made. Different scenarios for the supply of natural and recycled aggregates are studied and the scenarios for recycled aggregates procurement include different hypotheses for the installation (construction and demolition waste plant or quarry) processing the construction and demolition waste into recycled aggregates. For this case study and both regions, it was found that the supply of recycled aggregates produced at the construction and demolition waste plant has lower environmental impact and cost than all other scenarios, including the provision of natural aggregates, except when it is assumed that the quarry is licensed and equipped for receiving unsorted construction and demolition waste and processing it into recycled aggregates. The paper shows that transport distance is a determining factor in the comparison of the impacts of the procurement of natural and recycled aggregates. Moreover, in the Portuguese context, the environmental impacts of the procurement of recycled aggregates may be smaller than those of natural aggregates, but cost may be larger for recycled aggregates, preventing that the most sustainable option is chosen.

scholarly journals Preliminary Analysis of the Use of Construction Waste to Replace Conventional Aggregates in Concrete

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 81
Author(s):  
Fernando A. N. Silva ◽  
João M. P. Q. Delgado ◽  
António C. Azevedo ◽  
António G. B. Lima ◽  
Castorina S. Vieira
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Fine Aggregates ◽  
Mechanical Strengths

This work aims to study the influence of using construction and demolition waste in the replacement of coarse and fine aggregate to produce recycled aggregate concrete (RAC). A moderate compressive strength concrete made with usual fine and coarse aggregate was used as a benchmark material. Compressive and split tensile tests were performed using 120 cylindrical concrete specimens with 150 mm diameter and 300 mm length. Four-point flexural tests in reinforced beams made with conventional concrete and RAC were performed. The results obtained showed that the use of recycled fine aggregates, in both percentages of substitution investigated—50% and 100%— did not generate any deleterious influence on the values of compressive strength and split tensile strength of the RACs produced. Tin fact, the mechanical strengths of RACs produced with recycled fine aggregate were equal or higher than those from the reference concrete. The same behavior was not observed, however, when the recycled coarse aggregate was used. For this case, decreases in concrete mechanical strengths were observed, especially in compressive strength, with values around 35% lower when compared to the reference concrete. Tensile mechanical tests results confirmed the excellent behavior of all RACs made with replacement of usual fine aggregates by recycled. Bending tests performed in reinforced RAC beams had as objective to evaluate the deformation profile of the beams. The obtained results showed that RAC beams with full replacement of usual fine aggregate by the recycled aggregates have presented little changes in the global behavior, an aspect that encourages its use.

scholarly journals Effect of the Composition of Mixed Recycled Aggregates on Physical–Mechanical Properties

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1518
Author(s):  
Antonio López-Uceda ◽  
Enrique Fernández-Ledesma ◽  
Lorenzo Salas-Morera ◽  
José Ramón Jiménez ◽  
David Suescum-Morales
Keyword(s):  
Mechanical Properties ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Percentage Error ◽  
Demolition Waste ◽  
Ceramic Particles ◽  
Bituminous Materials ◽  
Natural Aggregates ◽  
Effect Of The Composition ◽  
Masonry Mortar

Recycled aggregates (RA) from construction and demolition waste are an alternative to natural aggregates in the construction sector. They are usually classified according to their composition. The main constituent materials are separated into the following categories: unbound natural aggregates, ceramic particles, cementitious particles, bituminous materials, and other materials considered impurities, such as glass, plastic, wood, or gypsum. In this research, a large number of samples of RA were collected from three different recycling plants and their properties were studied. After that, 35 samples were selected randomly, and their RA constituents were separated under laboratory conditions. Cementitious particles were differentiated into two subcategories: masonry mortar and concrete particles. Subsequently, their physical–mechanical properties were measured. The statistical analysis carried out exhibited that the constituents had a statistically significant influence on the physical–mechanical properties studied. Specifically, masonry mortar particles had higher water absorption and worse mechanical properties than concrete and ceramic particles. Secondly, multiple regression models were performed to predict the physical–mechanical properties of RA from their composition since mean absolute percentage error (MAPE) ranged between 0.9% and 8.6%. The differentiation in the subcategories of concrete and masonry mortar particles in compositional testing is useful for predicting the physical–mechanical properties of RA.

Production of Concrete Blocks with Residues for Civil Construction

2013 ◽  
Vol 690-693 ◽  
pp. 865-869 ◽  
Author(s):  
Marília Martinês de Camargo ◽  
Rosa Cristina Cecche Lintz ◽  
Luisa Andréia Gachet-Barbosa ◽  
Marta Siviero Guilherme Pires
Keyword(s):  
Value Added ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Structural Function ◽  
Demolition Waste ◽  
Original Product ◽  
Concrete Blocks ◽  
Function Blocks ◽  
Natural Aggregates

The Construction is recognized as one of the most important activities for the economic and social development, and on the other hand, behaves also as a major generator of environmental impacts, either by consumption of natural resources, the modification of the landscape or the generation of construction and demolition waste (CDW). Investing in an implementation of managed clean and healthy in the area of CDW is essential for the environment and for the economy of the cities, who are spending less resources on the collection, cleaning of drains and treatment of diseases. Nowadays, the amount of waste generated is considered large, occupying much space in landfills, and its transportation, depending on the volume and weight, is quite expensive. Recycling and reuse of these wastes are extremely important to control and mitigate environmental problems, as well as produce various materials value-added. Over 90% of waste can be recycled, reused and transformed into aggregates with characteristics very similar to the original product, thus creating environmentally friendly products such as sand, gravel, pebbles. This research concerns the study of the properties of concrete containing CDW, aiming its use in the manufacture of concrete blocks to seal without structural function. Blocks have been molded with partial replacement of natural aggregates by recycled aggregates and later were performed tests of compressive strength in accordance with the standards to prove the technical feasibility of the material for the trait studied.

Influence of Moisture States of Recycled Coarse Aggregates on the Slump Test

2013 ◽  
Vol 742 ◽  
pp. 379-383 ◽  
Author(s):  
Julia García González ◽  
Desirée Rodríguez Robles ◽  
Andrés Juan Valdés ◽  
Julia M. Morán del Pozo ◽  
M. Ignacio Guerra Romero
Keyword(s):  
Free Water ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Construction Sector ◽  
Inexpensive Method ◽  
Demolition Waste ◽  
Coarse Aggregates ◽  
Subsequent Elimination ◽  
Natural Aggregates

The use of recycled aggregate to produce new concretes has become increasingly widespread, and numerous studies have demonstrated that the final product performs similarly to traditional concrete. However, construction and demolition waste (CDW) presents certain characteristics which could limit its acceptance in the construction sector due to worse performance than natural aggregates. One example of this is water absorption, which in recycled aggregates reaches such high values that the amount of free water calculated for mixing the concrete is affected, consequently impacting on the concrete's properties, especially consistency. This paper reports the possibility of solving this problem with a simple and inexpensive method; pre-saturation of recycled aggregates prior to adding them to the mix. The results of two different pre-treatments are compared; one consisted of immersing the aggregates in water for 10 minutes and the other, in addition to the above procedure, included a brief period of air drying and subsequent elimination of surface water from the aggregate. Both pre-treatments were found to solve the problem of consistency.

scholarly journals Recommendations for the Management of Construction and Demolition Waste in Treatment Plants

Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1278
Author(s):  
Auxi Barbudo ◽  
Jesús Ayuso ◽  
Angélica Lozano ◽  
Manuel Cabrera ◽  
Antonio López-Uceda
Keyword(s):  
European Union ◽  
Construction Projects ◽  
Construction And Demolition Waste ◽  
Treatment System ◽  
Recycled Aggregates ◽  
The European Union ◽  
Demolition Waste ◽  
Natural Aggregates

Construction and demolition waste consists approximately of one third waste generated in the European Union. The recycling of this stream waste will provide ecological and sustainable benefits. Recycled aggregates from construction and demolition waste are clearing a path into civil constructions, as substitutes for natural aggregates. The possible applications of recycled aggregates on infrastructure construction projects will depend on the quality of the recycled aggregates mainly. This will be determined by the nature and the origin of the construction and demolition waste, and the treatment system undergone. Hence, this work proposes recommendations for the handling of construction and demolition waste in treatment plants.

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 Tests and Simulation of the Bond-Slip between Steel and Concrete with Recycled Aggregates from CDW

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 40
Author(s):  
Miguel Bravo ◽  
António P. C. Duarte ◽  
Jorge de Brito ◽  
Luís Evangelista
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Experimental Results ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Bond Slip ◽  
Model Code ◽  
Pull Out ◽  
Natural Aggregates

This works intends to analyze, experimentally and numerically, the bond-slip behavior between steel and concrete made with recycled aggregates (RA) from construction and demolition waste (CDW) from several recycling plants in Portugal. Pull-out tests performed in concrete mixes with RA from CDW are described and the main results (bond strength, bond-slip curves and failure modes) are shown and discussed. Additionally, a comparison between experimental and analytical (using equations from the literature) results is made. Afterwards, finite element (FE) models using Abaqus are developed and compared with the experimental results. The interface behavior between steel and concrete follows that prescribed by the CEB-FIP Model Code and uses as input experimental results. After validation, the models show good results when extended to predict the bond-slip behavior of the remaining concrete mixes studied. It is generally concluded that, per each 10% of natural aggregates replaced with RA from CDW, the bond strength decreases in circa 3% (numerically) to 5% (experimentally). CEB-FIP Model Code equations are shown to be able to predict bond strength and, when used in FE models, to lead to accurate simulation of the bond-slip response of steel and concrete with RA from CDW: the average ratio between numerical and experimental bond strengths is 0.95. In the scope of the FE models developed, a simple equation to be used along with those prescribed by CEB-FIP, which accounts for fraction and ratio of aggregates replaced, is put forward, as a first approach, showing good results.

scholarly journals Current Applications of Recycled Aggregates from Construction and Demolition: A Review

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1700
Author(s):  
Glaydson Simões dos Reis ◽  
Marco Quattrone ◽  
Weslei Monteiro Ambrós ◽  
Bogdan Grigore Cazacliu ◽  
Carlos Hoffmann Sampaio
Keyword(s):  
Raw Materials ◽  
Construction Materials ◽  
Cementitious Materials ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Construction Engineering ◽  
New Construction ◽  
Natural Aggregates ◽  
Environmentally Friendly Approach

A literature review comprising 163 publications published over a period of 26 years from 1992 to 2018 is presented in this paper. This review discusses the generation and recycling of construction and demolition waste (CDW) as well as its main uses as raw materials for the construction engineering sector. This review pays attention to the use of CDW aggregates for sand, pavements/roads, bricks, ceramics, cementitious materials, and concrete productions, as well its uses as eco-friendly materials for water decontamination. The physical-chemical and mechanical characteristics of recycled aggregates play an important role in their correctly chosen applications. The results found in this literature survey allow us to conclude that recycled aggregates from CDW can be successfully used to produce construction materials with quality comparable to those produced with natural aggregates. We concluded that the use of CDWs as raw materials for manufacturing new construction materials is technically feasible, economical, and constitutes an environmentally friendly approach for a future construction and demolition waste management strategy.

scholarly journals Recycled Aggregates from Construction and Demolition Waste in the Manufacture of Urban Pavements

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6605
Author(s):  
Manuel Contreras-Llanes ◽  
Maximina Romero ◽  
Manuel Jesús Gázquez ◽  
Juan Pedro Bolívar
Keyword(s):  
Precast Concrete ◽  
Breaking Load ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Waste Streams ◽  
Demolition Waste ◽  
Class 1 ◽  
Natural Aggregates ◽  
Precast Elements ◽  
Concrete Elements

Construction and Demolition Waste (CDW) is among the largest waste streams in the world. Therefore, within the Circular Economy concept, there is a growing interest in its reuse. The purpose of this work was to study the use of recycled aggregates (RAs) obtained by a specific separation method from CDW, replacing natural aggregates (NAs) in the manufacture of precast concrete elements, such as kerbstones and paver blocks. The physical and technological properties of precast products formulated with RAs were analysed in accordance with current regulations, comparing them with those of commercial products manufactured with NAs. The results indicated that partial or total substitution of NAs by RAs increased the water absorption and apparent porosity values of the precast elements while reducing the bulk density and compressive strength. However, all units manufactured with RAs showed breaking load values higher than the minimum required by EN 1338 and, in some cases, slightly higher average tensile strength values than the reference material. In addition, some of the compositions including RAs gave rise to pieces that, according to their flexural strength, were classified as class 1 and marked S in accordance with EN 1340. According to abrasion resistance, in most cases, the precast elements are classified as Class 4 and I (≤20 mm). Finally, precast concrete produced from RAs satisfies the tolerance requirements for classification as class 3 (≤1.5 kg m−2). Therefore, it could be suitable for use in high pedestrian or traffic areas.

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