scholarly journals Caracterización físico-mecánica del hormigón estructural fabricado con áridos reciclados: comparativa experimental con sustitución de áridos finos y gruesos = Physical-mechanical characterization of the structural concrete made with recycled aggregates: experimental comparative with substitution of fine and coarse aggregates

2017 ◽  
Vol 3 (1) ◽  
pp. 24
Author(s):  
Sara Valverde Fernández
Keyword(s):  
Water Absorption ◽  
Modulus Of Elasticity ◽  
Shrinkage Strain ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Coarse Aggregates ◽  
Static Modulus ◽  
Static Modulus Of Elasticity

ResumenEste trabajo estudia las propiedades mecánicas y físicas de hormigones estructurales fabricados con áridos reciclados obtenidos de residuos de construcción y demolición. Se han seleccionado mezclas con una relación específica agua / cemento y una sustitución de agregados gruesos y finos similares. Se han comparado los resultados de la deformación, la resistencia a la compresión, la resistencia a la rotura por fraccionamiento, el módulo estático de elasticidad, la deformación por contracción, la densidad aparente y los ensayos de absorción de agua. Los datos muestran que las propiedades más afectadas debido a la sustitución de agregados naturales por agregados reciclados son la trabajabilidad, el módulo de elasticidad, la deformación por contracción y la absorción de agua.AbstractThis work studies the mechanical and physical properties of structural concretes made by recycled aggregates obtained from construction and demolition waste. Mixes with a specific water/cement ratio and a similar coarse and fine aggregate substitution have been selected. Results from slump, compressive strength, splitting tensile strength, static modulus of elasticity, shrinkage strain, bulk density and water absorption tests have been compared. The data show that the most affected properties because of natural aggregate substitution for recycled aggregates are workability, modulus of elasticity, shrinkage strain and water absorption.

scholarly journals Incorporation of recycled aggregates from construction and demolition waste in paver blocks

2020 ◽  
Vol 13 (4) ◽  
Author(s):  
Cinthia Maia Pederneiras ◽  
Maria Del Pilar Durante ◽  
Ênio Fernandes Amorim ◽  
Ruan Landolfo da Silva Ferreira
Keyword(s):  
Natural Resources ◽  
Mechanical Strength ◽  
Reference Sample ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
World Population ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Concrete Blocks ◽  
Modified Block

ABSTRACT: The consumption of natural resources and energy increased proportionally with the growth of the world population and its economic level. There was an increasing exponential consumption of natural resources, which implied an increase in environmental impacts. The construction sector is responsible for a very significant production of construction and demolition waste (CDW). Thus, there is a concern in search of a more sustainable final disposal. Many studies have been investigated the development of new materials with the incorporation of recycled aggregates from CDW. This paper presents a study of performance evaluation of concrete blocks produced with CDW. For that purpose, an experimental campaign was performed, including a characterization of the aggregates used. The incorporation of 100% of fine and coarse recycled aggregates. The mixtures were designed according to the condition of the aggregate (dry, washed or saturated). The performance of these blocks was evaluated in terms of mechanical strength and water absorption. Some additional tests were also performed to deeper analyze of the microstructure of these blocks. To assess the durability of the concrete blocks, a full-scale road was built. The results were very positive, since there were no significant differences between the modified concrete blocks and the reference sample (0% of the CDW). The modified block with fine aggregate presented the best performance of all the blocks, concerning mechanical strength. In addition, the performance of concrete blocks with washed recycled aggregates had a better performance compared to the others. The results obtained were satisfactory for the application of the blocks in the streets with low movement and low load.

scholarly journals Compressive Strength of Concrete with Construction and Demolition Waste and m-SAND using Additives

2019 ◽  
Vol 8 (2S10) ◽  
pp. 935-937
Keyword(s):  
Compressive Strength ◽  
Green Building ◽  
Cost Effective ◽  
Construction And Demolition Waste ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Rapid Urbanization ◽  
Manufactured Sand ◽  
Coarse Aggregates

Construction and Demolition wastes(C&D wastes) are generated in all cities of the world due to rapid urbanization. Disposing C & D waste these days is a costly affair, and raises environmental issues. Hence an attempt is made to reuse the demolished concrete as a partial replacement of natural coarse aggregates. Also due to ban of sand mining by local authorities, the cost of natural fine aggregate is very high and itself becoming a scarce material. Hence crushed stone aggregates called manufactured sand (m sand) is used, totally replacing natural fine aggregates. This concept is found to be cost effective, minimizes disposal of C & D wastes, and leads towards Green Building Concepts. Compression test on M40 concrete cubes of size 150mmx150mmx150mm are conducted at end of 7 days and 28days. Mix design for M40 concrete is made in accordance to IS: 10262-2019 with water cement ratio of 0.45 using 53 Grade Ordinary Portland cement. Superplasticizer (LIQUIFIX) is used to enhance workability. Nano Silica (NS)(1.5% by weight of cement),Wollastonite powder(WP)(10%by weight of cement) and Basalt fibres(BF)(1% by weight of cement) are added as additives. It is observed, that compressive strength of 7 days and 28 days cured samples is 25% more with the addition of all three additives compared to samples without additives. Hence the loss of compressive strength obtained by using demolished concrete as aggregates and m sand in concrete is regained with the addition of additives.

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>

Non Destructive Testing of Concrete with Recycled Cement Powder

2016 ◽  
Vol 825 ◽  
pp. 45-48 ◽  
Author(s):  
Tereza Pavlů ◽  
Magdaléna Šefflová
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Absorption Capacity ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Aggregate Concrete ◽  
Cement Powder

This study deals with determination of the physical properties of fine-aggregate concrete with partial replacement of cement in concrete mixture. Cement was replaced by recycled cement powder originating from construction and demolition waste. The main goal of this study is evaluation of the basic physical properties of the fine-aggregate concrete with partial cement replacement by recycled concrete powder such as density, water absorption capacity and capillary water absorption. The fine recycled concrete which was used as partial replacement of cement had the same grain size as cement. The replacement rate was 0 %, 5 %, 10 % and 15 %. Physical properties were investigated by using cubic and prismatic specimens.

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 Evaluation of the strength of concretes produced with recycled CDW aggregates originating from a housing project located in Pernambuco, Brazil

2021 ◽  
Vol 10 (5) ◽  
pp. e6610514583
Author(s):  
Renan Gustavo Pacheco Soares ◽  
Gustavo Gutierrez de Oliveira Rodrigues ◽  
Emylle Kerolayne Palmeira de Andrade ◽  
Carla Renata Xavier Pacheco ◽  
Lyneker Souza de Moura ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Urban Areas ◽  
Good Alternative ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Coarse Aggregates ◽  
Construction Techniques ◽  
Three Samples ◽  
Hardened State

In view of the improvement of construction techniques and technological innovations, civil construction still faces numerous problems. Uncontrolled exploitation of natural resources has caused major environmental impacts, in addition to the generation and accumulation of debris in urban areas. Thus, recycling appears as a sustainable alternative to reduce the accumulation of this waste. As an option, there is the use of Recycled Aggregates, obtained through Construction and Demolition Waste (CDW). In this sense, the present study aimed to analyze the feasibility of using the CDW through its application in the production of recycled coarse aggregates in concrete. For the tests, the coarse aggregate was replaced in the proportions of 0 (reference line), 10, 20, 30, 40, 50 and 100%, with three samples for each line and age. The dosage of the strokes followed the parameters established by the IPT / EPUSP method. The concretes were analyzed for compressive strength at 7, 14 and 28 days and the samples were evaluated for properties in an anhydrous, fresh and hardened state. The data collected in the tests were tabulated and analyzed for the degree of addition and its correlation with the characteristic resistance. The results allowed to conclude that the use of the residue in the form of aggregate for the concrete, in the proportions of 10% and 20%, does not affect the compressive strength, making it a good alternative.

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.

Applicability of models provided by technical standards to estimate the static modulus of elasticity of concretes produced with recycled coarse aggregates

2020 ◽  
Author(s):  
Fernando Henrique F. Sousa ◽  
Claudio de Souza Kazmierczak ◽  
Uziel C. D. M. Quinino ◽  
Ana Júlia M. M. Fernandes ◽  
Marlova Piva Kulakowski
Keyword(s):  
Modulus Of Elasticity ◽  
Technical Standards ◽  
Coarse Aggregates ◽  
Static Modulus ◽  
Static Modulus Of Elasticity

scholarly journals Material Characterization for Sustainable Concrete Paving Blocks

2019 ◽  
Vol 9 (6) ◽  
pp. 1197 ◽  
Author(s):  
Xinyi Wang ◽  
Chee Chin ◽  
Jun Xia
Keyword(s):  
Water Absorption ◽  
Crumb Rubber ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Waste Materials ◽  
Fine Aggregate ◽  
Significant Deterioration ◽  
Sustainable Concrete ◽  
Coarse Aggregates ◽  
Slip Resistance

Recycled aggregates have been widely studied and used in concrete products nowadays. There are still many waste materials that can be used as recycled aggregates other than crushed concrete particles. This paper aims to study the property variations of sustainable concrete paving block incorporating different contents of construction wastes. Five different types of waste materials were used in this project, including: recycled concrete coarse aggregate (RCCA), recycled concrete fine aggregate (RCFA), crushed glass (CG), crumb rubber (CB), and ground granulated blast furnace slag (GGBS). According to the test results of the properties of blocks mixed with different levels of wastes materials, it is concluded that adding both RCCA and RCFA in the block can decrease its strength and increase the water absorption. The suggested replacement levels for RCCA and RCFA are 60% and 20%, respectively. Mixing crushed glass in the concrete paving blocks as a type of coarse aggregates can improve the blocks’ strength and decrease the blocks’ water absorption. Addition of crumb rubber causes a significant deterioration of blocks’ properties except for its slip resistance.

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.

Sign in / Sign up

Export Citation Format

Share Document