scholarly journals The influence of RCA addition on selected parameters of concrete

2018 ◽  
Vol 196 ◽  
pp. 02018
Author(s):  
Roman Jaskulski ◽  
Marcin Supera ◽  
Wojciech Kubissa ◽  
Peter Koteš ◽  
Miroslav Brodňan
Keyword(s):  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Test Results ◽  
Recycled Concrete Aggregate ◽  
Average Quality ◽  
Durability Test ◽  
Natural Aggregate ◽  
Concrete Mixtures

The main goal of this research was to evaluate the effects of using recycled concrete aggregate (RCA) of an average quality as a 50% replacement for natural coarse aggregate. A total of 26 concrete mixtures were prepared, 13 containing RCA as a 50% of coarse aggregate and the same number of mixes only with natural aggregate (NA). The results show the influence of the RCA incorporation on concretes for the same w/c ratio. Both mechanical and durability parameters of the concretes made with recycled aggregate are worse, and the differences increase for low w/c ratio. Despite the reduction of these parameters in relation to concretes with only NA, both mechanical and durability test results obtained for concrete series with RCA can be described as good.

scholarly journals Influence of Partial Coarse Fraction Substitution of Natural Aggregate by Recycled Concrete Aggregate in Hot Asphalt Mixtures

2019 ◽  
Vol 12 (1) ◽  
pp. 250 ◽  
Author(s):  
Debora Acosta Álvarez ◽  
Anadelys Alonso Aenlle ◽  
Antonio José Tenza-Abril ◽  
Salvador Ivorra
Keyword(s):  
Asphalt Concrete ◽  
Coarse Fraction ◽  
Asphalt Mixtures ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Demolition Waste ◽  
Natural Aggregate

The main objective of this work is to evaluate the properties of hot asphalt mixtures that have been manufactured with different recycled concrete aggregate (RCA) percentages (0%, 20%, 40%, 60% and 80% of the fraction 5–13 mm) and asphalt (4%, 4.5% and 5%). Dense asphalt mixtures were made; partially replacing the natural aggregate (NA) fraction between 5 and 13 mm. Marshall specimens were manufactured to determine the main properties of the asphalt concrete (AC) in terms of density, voids, stability and deformation. Additionally, the optimal asphalt content (OAC) was determined, and measured the water sensibility, the stiffness modulus and the permanent deformation. The results corroborate the potential for using these sources of construction and demolition waste (CDW) as a RCA in asphalt concrete and show that the hot asphalt mixtures with up to 40% substitution of natural aggregate by recycled aggregate in the fraction 5–13 mm present good behavior.

Study on Properties of Self-Compacting Concrete Prepared with Coarse Recycled Concrete Aggregate

2014 ◽  
Vol 638-640 ◽  
pp. 1494-1498 ◽  
Author(s):  
Jian Jie Yu ◽  
Jian Gong ◽  
Jie Ming Zou ◽  
Wei Kang Yang
Keyword(s):  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Working Environment ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Self Compacting Concrete ◽  
Recycled Coarse Aggregate ◽  
Concrete Mixtures ◽  
Crushed Concrete ◽  
Construction Efficiency

Self-compacting concrete is absent of vibration noise during casting, improves the construction efficiency, and provides a healthier working environment compared to the traditional vibrated concrete. The potential coarse recycled aggregate obtained from crushed concrete for making self-compacting concrete was considered to replace the aggregate with the percentage of substitution of recycled coarse aggregate 0%, 50% and 100%. Thus, three types of concrete mixtures were made. Experiments show that, the properties of these concrete only have slight differences and recycled coarse aggregate can be successfully used for the preparation of self-compacting concrete. The method solves the problem of the waste disposal by the demolition of old buildings.

scholarly journals Drying Shrinkage and Rapid Chloride Penetration Resistance of Recycled Aggregate Concretes Using Cement Paste Dissociation Agent

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1478
Author(s):  
Sungchul Yang ◽  
Hyewon Lee
Keyword(s):  
Cement Paste ◽  
Drying Shrinkage ◽  
Experimental Tests ◽  
Preliminary Test ◽  
Chloride Penetration ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Test Results ◽  
Durability Test

In the present study, a recycled concrete aggregate (RCA) coating treatment using a cement paste dissociation agent (CPDA) with different mixing methods was newly incorporated in RCA concrete mixtures. First, a preliminary test program was conducted to determine the proper dosage of the CPDA solution throughout its RCA concrete test results from compressive strength, flexural strength, and elastic modulus. Then, a series of experimental tests were carried out to investigate the effect of RCA coating treatment, different mixing method such as the equivalent mortar volume (EMV) method and conventional method, and different RCA replacement ratios on durability test results of RCA concrete such as drying shrinkage values and rapid chloride penetration test (RCPT) values. The test results showed that all RCA concretes mixed with the coated RCAs were found to be workable regardless of different mix methods, with the slump and air contents of all the mixes being almost identical. All the concrete specimens, which were mixed with the coated RCAs with CPDA solution, represented lower drying shrinkage and RCPT values than those mixed without RCA coating treatment, regardless of different mix proportioning methods or RCA replacement ratios. This holds for the concrete specimens proportioned with the EMV method, regardless of different RCA replacement ratios.

scholarly journals Utilization of Demolished Waste as Coarse Aggregate in Concrete

2019 ◽  
Vol 5 (3) ◽  
pp. 540 ◽  
Author(s):  
Abdulsamee M Halahla ◽  
Mohammad Akhtar ◽  
Amin H. Almasri
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
International Standards ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Test Results ◽  
Aggregate Concrete ◽  
Natural Aggregate ◽  
Concrete Building

Demolishing concrete building usually produces huge amounts of remains and wastes worldwide that have promising possibilities to be utilized as coarse aggregate for new mixes of concrete. High numbers of structures around the world currently need to be removed for several reasons, such as reaching the end of the expected life, to be replaced by new investments, or were not built by the local and international standards. Maintaining or removal of such structures leads to large quantities of concrete ruins. Reusing these concrete wastes will help in saving landfill spaces in addition to more sustainability in natural resources. The objective of this study is to investigate the possibility of using old recycled concrete as coarse aggregate to make new concrete mixes, and its effect on the evolution of the compressive strength of the new concrete mixes.  Core samples for demolished concrete were tested to determine its compressive strength. The core test results can be thought of as aggregate properties for the new concrete. Then, the compressive strength and splitting tensile strength of the new recycled aggregate concrete (RAC) were determined experimentally by casting a cubes and cylinders, respectively. It was found that the evolution of compressive strength of recycled aggregate concrete is similar in behavior to the concrete with natural aggregate, except that it is about 10% lower in values. It was also seen that water absorption for recycled aggregate is noticeably higher than that for natural aggregate, and should be substituted for in the mix design.

Effect of Water Reducing Admixtures and Construction Variability in Concrete Containing Recycled Aggregate Concrete

2021 ◽  
Vol 47 (3) ◽  
pp. 456-464
Author(s):  
Claude Villiers
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Target Strength ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Effect Of Water ◽  
Concrete Mixtures ◽  
Concrete Mix

The objectives of this project are to evaluate the effect of water reducing admixtures and construction variability in concrete mixtures containing recycled concrete aggregate (RCA). A concrete mix that was approved for curbs and sidewalks in the State of Florida was selected. Based on the analysis conducted, it was found that properties of the RCA were comparable to the virgin aggregate used in this project. However, the absorption of the RCA was double as compared to the limestone. Although the compressive strength of the virgin mix was decreased by 19% when RCA was introduced into the mix, both mixes met the target strength (17.2 MPa). Admixture has a significant impact on all the mixes, especially on mixes that contained RCA. When admixture was omitted, the 28-day compressive strength dropped to nearly 55% on the mixture containing RCA. In addition, the RCA mix without the admixture did not reach the target strength at 28 days. Similarly, construction variability has a significant effect on the compressive strength of the mixes. When the RCA content was increased by 15% and 25% respectively, the concrete paste was weak. These mixtures did not meet the target strength at 28 days.

Influence of Recycled Aggregate Quality on Recycled Concrete

2015 ◽  
Vol 1106 ◽  
pp. 45-48 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Tereza Pavlů
Keyword(s):  
Negative Influence ◽  
Recycled Concrete ◽  
The Other ◽  
Recycled Aggregate ◽  
Test Results ◽  
The Czech Republic ◽  
Natural Aggregate ◽  
Concrete Mixtures ◽  
Reference Mixture

This article deals with the influence of recycled aggregate quality on recycled concrete. Replacement of natural aggregate by recycling aggregate has a negative influence on the properties of concrete. Three types of recycled aggregate were used for the production of concrete. The samples of recycled aggregate were obtained from two recycling plants in the Czech Republic. The samples of recycled aggregate were tested by pycnometric method. From the test results, a different quality of recycled aggregate was discovered. For the testing of concrete, a total of eight concrete mixtures were made, one of which was a reference mixture and the natural aggregate was replaced by recycled aggregate of varying ratio in the other mixtures. Finally, it is possible to say that use of recycled aggregate in concrete influences the properties of concrete. This influence depends on the quality and amount of recycled aggregate in the concrete.

scholarly journals Durability Properties of Modified Self Compacting Concrete with Recycled Concrete Aggregate

2019 ◽  
Vol 9 (1) ◽  
pp. 5102-5106
Keyword(s):  
Natural Resources ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Sustainable Construction ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Self Compacting Concrete ◽  
Demolition Waste ◽  
Durability Properties

In recent years, sustainable construction materials are highly recommended in construction projects due to reduce the degradation of natural resources. An experimental investigation with varying percentages of coarse recycled concrete aggregate was conducted on self-compacting concrete. The primary goal was to explore the suitability and impact of coarse recycled aggregate in concrete fresh generation. The demand for building products has risen tremendously in latest years, so the quantity of building and demolition waste has increased, placing enormous stress to the atmosphere. The use of recycled aggregate in concrete is a suitable solution to extend the lifetime of natural resources and thereby lead to sustainable developments in construction field. In this investigation, SCC is modified by recycled coarse aggregate (RCA) in various percentages of natural coarse aggregate (NCA) substitutes from 0 percent to 100 percent with a 20 percent increase. Durability and the mechanical properties of modified SCC was determined. From the results it is revealed that the substitution of RCA in the place of NCA significantly improved the durability properties.

A review of experimental results on structural performance of reinforced recycled aggregate concrete beams and columns

2020 ◽  
Vol 23 (15) ◽  
pp. 3351-3369 ◽  
Author(s):  
Simret T Deresa ◽  
Jinjun Xu ◽  
Cristoforo Demartino ◽  
YeongAe Heo ◽  
Zhi Li ◽  
...  
Keyword(s):  
Concrete Beams ◽  
Reinforcement Ratio ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Experimental Results ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Aggregate Concrete ◽  
Natural Aggregate

This article presents a comprehensive and critical review of the structural performances of reinforced recycled aggregate concrete beams and columns based on experimental results reported in the literature. Extensive data sets collected from the literature are categorized to investigate the effects on the local and global structural behavior. First, the flexural and shear response of reinforced recycled aggregate concrete beams is discussed. The structural performances are reviewed focusing on the main geometric and material variables such as the recycled concrete aggregate replacement ratio, the longitudinal reinforcement ratio, the transverse reinforcement ratio, and the shear span-to-depth ratio. Then, the behavior of reinforced recycled aggregate concrete columns under concentric and eccentric compressive loads and the seismic performance under low cyclic loading are discussed. The similarities and the differences between reinforced recycled aggregate concrete and reinforced natural aggregate concrete beams and columns are highlighted. The need for further research is pointed out at the end of the article. The results reported in this review clearly indicate that reinforced recycled aggregate concrete beams and columns with various recycled concrete aggregate replacement ratios have comparable or slightly lower structural performances to the reinforced natural aggregate concrete ones indicating the feasibility of recycled concrete aggregate for structural applications.

scholarly journals Use of Prefabrication, Construction and Demolition Wastes as an Aggregate in Vibropressed Precast Concrete Blocks Production

2022 ◽  
Vol 11 (1) ◽  
pp. 20-28
Author(s):  
Grzegorz Łój ◽  
Wiesława Nocuń-Wczelik
Keyword(s):  
Precast Concrete ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Partial Substitution ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Concrete Technology ◽  
Natural Sand ◽  
Natural Aggregate ◽  
Concrete Blocks

The aim of current study was to determine the recycled concrete aggregate (RCA) applicability in the production of concrete mixture for vibropressed concrete blocks. The experiments were focused especially on the crushed waste material from the same concrete elements producing plant.  For this type of precast elements only some finer fractions can be implemented and the “earth-moist” consistency of fresh mixture is required. The series of samples was prepared in which the mixture of natural aggregates was partially or totally substituted by recycled concrete aggregate. The 0/4 RCA fraction, which is usually rejected in ready mix concrete technology, plays a role of 0/2 sand.  The substitution of sand fraction was from 20% to 100% respectively. The substitution of the coarser aggregate fractions by 4/16 RCA was also done. The standard properties of vibropressed elements, such as the degree of densification, the density of material, the compressive and splitting tensile strength and the water absorption capacity according to the relevant standards were determined. The parameters of materials with the natural aggregate substitution by RCA are affected by the ratio of recycled concrete aggregate. In most cases the results do not decline specially from those for reference samples, when only the natural sand (0/2) fraction is substituted by the 0/4 recycled aggregate. As one could expect, as lower the substitution, as better the test results. The partial substitution of natural aggregate by coarser fractions requires experimental verification; over 20% substitution of natural aggregate by 4/8, 8/16 or 0/16 RCA should be excluded.

Thermal Properties of Concrete with Recycled Aggregate

2014 ◽  
Vol 1054 ◽  
pp. 227-233 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Martin Volf ◽  
Tereza Pavlů
Keyword(s):  
Thermal Properties ◽  
Building Materials ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Conventional Concrete ◽  
Concrete Mixtures ◽  
Reference Mixture

Currently, the emphasis is put on sustainable buildings; simultaneously, the emphasis is put on energy efficiency in buildings, with respect to this fact of necessity to test thermal properties of new building materials. This article deals with the thermal properties of concrete containing recycled concrete aggregate. Four types of recycled concrete aggregate were used for the production of the concrete. For the testing of concrete, a total of ten concrete mixtures were made, one of which was a reference mixture and the natural aggregate was replaced by recycled aggregate of varying ratio in the other mixtures. Finally, it is possible to say that according to the thermal properties of the recycled aggregate concrete is possible to be used in the same applications as conventional concrete.

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