Properties of concrete having treated recycled coarse aggregate and slag

The possibility of using substitute materials for aggregates and cement in concrete were studied and reported in this paper. Concrete mixtures with untreated recycled coarse aggregates (URCA) and treated recycled coarse aggregates (TRCA) were used to prepare two mix groups of without slag (Mix I) and with slag (Mix II). The recycled aggregates were treated with hydrochloric acid (HCl) having different molarities (0.1M, 0.3M and 0.5M) before used as a substitute material for virgin aggregate in concrete. The concrete mechanical, durability properties and morphology of concrete were examined through standard experiments and analysed. In both mix groups considerable improvement in all characteristics were identified in TRCA mixes than URCA mixes. Among the two mix groups the concrete mix with slag (Mix II) showed better durability characteristics than mix without slag (Mix I). The combination of TRCA and slag in concrete substantially increases the characteristics of concrete in all means.

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Effect of Recycled Coarse Aggregates in Properties of Concrete

Journal of Green Building ◽

10.3992/jgb.3.4.130 ◽

2008 ◽

Vol 3 (4) ◽

pp. 130-137 ◽

Cited By ~ 1

Author(s):

R Kumutha ◽

K Vijai

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Flexural Strength ◽

Modulus Of Elasticity ◽

Coarse Aggregate ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Split Tensile Strength ◽

Coarse Aggregates ◽

The Cost

The properties of concrete containing coarse recycled aggregates were investigated. Laboratory trials were conducted to investigate the possibility of using recycled aggregates from the demolition wastes available locally as the replacement of natural coarse aggregates in concrete. A series of tests were carried out to determine the density, compressive strength, split tensile strength, flexural strength and modulus of elasticity of concrete with and without recycled aggregates. The water cement ratio was kept constant for all the mixes. The coarse aggregate in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% recycled coarse aggregates. The test results indicated that the replacement of natural coarse aggregates by recycled aggregates up to 40% had little effect on the compressive strength, but higher levels of replacement reduced the compressive strength. A replacement level of 100% causes a reduction of 28% in compressive strength, 36% in split tensile strength and 50% in flexural strength. For strength characteristics, the results showed a gradual decrease in compressive strength, split tensile strength, flexural strength and modulus of elasticity as the percentage of recycled aggregate used in the specimens increased. 100% replacement of natural coarse aggregate by recycled aggregate resulted in 43% savings in the cost of coarse aggregates and 9% savings in the cost of concrete.

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Examining Polyethylene Terephthalate (PET) as Artificial Coarse Aggregates in Concrete

Civil Engineering Journal ◽

10.28991/cej-2020-03091626 ◽

2020 ◽

Vol 6 (12) ◽

pp. 2416-2424

Author(s):

Erniati Bachtiar ◽

Mustaan Mustaan ◽

Faris Jumawan ◽

Meldawati Artayani ◽

Tahang Tahang ◽

...

Keyword(s):

Compressive Strength ◽

Flexural Strength ◽

Polyethylene Terephthalate ◽

Coarse Aggregate ◽

Fresh Concrete ◽

Coarse Aggregates ◽

Volume Weight ◽

Concrete Mixtures ◽

Strength Tests ◽

Recycled Polyethylene

This study aims to examine the effect of recycled Polyethylene Terephthalate (PET) artificial aggregate as a substitute for coarse aggregate on the compressive strength and flexural strength, and the volume weight of the concrete. PET plastic waste is recycled by heating to a boiling point of approximately 300°C. There are five variations of concrete mixtures, defined the percentage of PET artificial aggregate to the total coarse aggregate, by 0, 25, 50, 75 and 100%. Tests carried out on fresh concrete mixtures are slump, bleeding, and segregation tests. Compressive and flexural strength tests proceeded based on ASTM 39/C39M-99 and ASTM C293-79 standards at the age of 28 days. The results showed that the use of PET artificial aggregate could improve the workability of the concrete mixture. The effect of PET artificial aggregate as a substitute for coarse aggregate on the compressive and flexural strength of concrete is considered very significant. The higher the percentage of PET plastic artificial aggregate, the lower the compressive and flexural strength, and the volume weight, of the concrete. Substitution of 25, 50, 75 and 100% of PET artificial aggregate gave decreases in compressive strength of 30.06, 32.39, 41.73 and 44.06% of the compressive strength of the standard concrete (18.20 MPa), respectively. The reductions in flexural strength were by respectively 19.03, 54.50, 53.95 and 61.00% of the standard concrete's flexural strength (3.59 MPa). The reductions in volume weight of concrete were by respectively 8.45, 17.71, 25.07 and 34.60% of the weight of the standard concrete volume of 2335.4 kg/m3 Doi: 10.28991/cej-2020-03091626 Full Text: PDF

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Sustainability of Construction Aggregates in Kuwait

The Academic Research Community Publication ◽

10.21625/archive.v2i4.384 ◽

2019 ◽

Vol 2 (4) ◽

pp. 406

Author(s):

Sharifa Al-Fadala

Keyword(s):

Construction Industry ◽

United Arab Emirates ◽

Coarse Aggregate ◽

Waste Utilization ◽

Recycled Aggregates ◽

Environmental Pressures ◽

Coarse Aggregates ◽

Constituent Material ◽

Construction And Demolition Wastes ◽

Local Construction

Kuwait is facing a current construction boom with projects worth of more than USD188bn. The huge infrastructure spending plan of Kuwait is reflected with a growing demand of concrete as concrete is the most commonly used building material in the local construction. At the present, the quarrying of coarse aggregate which is a main concrete constituent material is banned in Kuwait since 1997 and construction industry depends on the imported coarse aggregates from neighbouring sources such as United Arab Emirates and Iran. Kuwait is also interested in challenging the growing concern of an effective environmental management of water, land and atmosphere to achieve a sustainable civilization. The increasingly environmental pressures coupled with the limited available economical resources are causing the decision making authorities to consider the practice of recycling and waste utilization. This paper presents Kuwait Institute for Scientific Research (KISR) efforts to investigate sustainable sources of coarse aggregate for construction industry from waste. The first sustainable source investigated is the production of synthetic lightweight aggregates utilizing combinations of argillaceous indigenous and waste materials, and the second is recycled aggregates from construction and demolition wastes. The potential of the two sustainable sources of construction aggregates are presented and the needed steps for real industrial application are addressed.

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Performance Enhancement of Recycled Aggregate Concrete – An Experimental Study

Applied Science and Engineering Progress ◽

10.14416/j.asep.2021.07.003 ◽

2021 ◽

Author(s):

Sivamani Jagan ◽

Thurvas Renganathan Neelakantan ◽

Palaniraj Saravanakumar

Keyword(s):

Mechanical Properties ◽

Experimental Study ◽

Elastic Modulus ◽

Performance Enhancement ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Aggregate Concrete ◽

Coarse Aggregates ◽

Durability Properties ◽

Concrete Mixtures

Extensive studies have been performed on the mechanical and durability properties of the concrete prepared with recycled coarse aggregates (RCA), however, only modest consideration has been given to the studies on the behaviour of RAC prepared by alternative mixing approach techniques. This study presents the mechanical properties of the recycled aggregate concrete (RAC) with different percentages of RCA prepared by normal mixing approach (NMA), two-stage mixing approach (TSMA) and sand enveloped mixing approach (SEMA) techniques. The manufactured concrete mixtures were tested for compression, tension, flexure and elastic modulus at 7, 28 and 90 days. The results indicate that the mechanical properties of the RAC (with 100% of RCA) prepared through TSMA and SEMA were improved by 9.36 and 12.14% at 28 days. Perhaps, prolonged curing to TSMA and SEMA mixtures improved the mechanical properties of the RAC that is nearly equal to normal aggregate concrete (NAC) prepared by NMA.

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A Study on Suitability of EAF Oxidizing Slag in Concrete: An Eco-Friendly and Sustainable Replacement for Natural Coarse Aggregate

The Scientific World JOURNAL ◽

10.1155/2015/972567 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 11

Author(s):

Alan Sekaran ◽

Murthi Palaniswamy ◽

Sivagnanaprakash Balaraju

Keyword(s):

Fly Ash ◽

Coarse Aggregate ◽

Experimental Investigations ◽

Alternative Source ◽

Conventional Concrete ◽

Great Opportunity ◽

Coarse Aggregates ◽

Durability Properties ◽

Fast Pace ◽

C 30

Environmental and economic factors increasingly encourage higher utility of industrial by-products. The basic objective of this study was to identify alternative source for good quality aggregates which is depleting very fast due to fast pace of construction activities in India. EAF oxidizing slag as a by-product obtained during the process in steel making industry provides great opportunity to utilize it as an alternative to normally available coarse aggregates. The primary aim of this research was to evaluate the physical, mechanical, and durability properties of concrete made with EAF oxidizing slag in addition to supplementary cementing material fly ash. This study presents the experimental investigations carried out on concrete grades of M20 and M30 with three mixes: (i) Mix A, conventional concrete mix with no material substitution, (ii) Mix B, 30% replacement of cement with fly ash, and (iii) Mix C, 30% replacement of cement with fly ash and 50% replacement of coarse aggregate with EAF oxidizing slag. Tests were conducted to determine mechanical and durability properties up to the age of 90 days. The test results concluded that concrete made with EAF oxidizing slag and fly ash (Mix C) had greater strength and durability characteristics when compared to Mix A and Mix B. Based on the overall observations, it could be recommended that EAF oxidizing slag and fly ash could be effectively utilized as coarse aggregate replacement and cement replacement in all concrete applications.

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Mechanical Properties of Geopolymer Concrete Made With Partial Replacement of Coarse Aggregate by Recycled Aggregate

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.f9124.109119 ◽

2019 ◽

Vol 9 (1) ◽

pp. 2301-2304 ◽

Cited By ~ 1

Keyword(s):

Mechanical Properties ◽

Sodium Hydroxide ◽

Sodium Silicate ◽

Coarse Aggregate ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Partial Replacement ◽

Geopolymer Concrete ◽

Recycled Coarse Aggregate ◽

Coarse Aggregates

Construction is the one the fast growing field in the worldwide. There are many environmental issues connected with the manufacture of OPC, at the same time availability of natural coarse aggregate is getting reduced. Geopolymer binder and recycled aggregates are promising alternatives for OPC and natural coarse aggregates. It is produced by the chemical action of inorganic molecules and made up of Fly Ash, GGBS, fine aggregate, coarse aggregate and an alkaline solution of sodium hydroxide and sodium silicate. 10 M sodium hydroxide and sodium silicate alkali activators are used to synthesis the geopolymer in this study. Recycled aggregates are obtained from the construction demolished waste. The main focus of this work is to find out the mechanical properties of geopolymer concrete of grade G40 when natural coarse aggregate(NCA) is replaced by recycled coarse aggregate in various proportions such as 0%, 10%, 20%, 30%,40% and 50% and also to compare the results of geopolymer concrete made with recycled coarse aggregates(RAGPC) with geopolymer concrete of natural coarse aggregate(GPC) and controlled concrete manufactured with recycled aggregates(RAC) and controlled concrete of natural coarse aggregates(CC) of respective grade. It has been observed that the mechanical properties are enhanced in geopolymer concrete, both in natural coarse aggregate and recycled coarse aggregate up to 30% replacement when it is compared with the same grade of controlled concrete.

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Quality Improvement of Recycled Aggregate Concrete using Six Sigma DMAIC Methodology

International Journal of Mathematical Engineering and Management Sciences ◽

10.33889/ijmems.2020.5.6.104 ◽

2020 ◽

Vol 5 (6) ◽

pp. 1409-1419

Author(s):

Suhas Vijay Patil ◽

Balakrishna Rao K. ◽

Gopinatha Nayak

Keyword(s):

Six Sigma ◽

Coarse Aggregate ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Lower Grade ◽

Test Results ◽

Aggregate Concrete ◽

Recycled Coarse Aggregate ◽

Concrete Mix

Recycled aggregates (RA) are obtained from construction and demolished waste, laboratory crushed concrete and concrete waste at RMC plants. The concrete made from recycled aggregate is known as recycled aggregate concrete. The use of recycled aggregate is very beneficial to the environment in civil works. Its usage also helps in financial saving as the cost of transportation and production energy cost of natural coarse aggregate (NCA) is reduced. In India, the recycled aggregate application in lower grade concrete work is observed. However, the effect of recycled aggregate on the strength and durability of concrete restricts its use in higher-grade work. This paper presents a series of tests carried out on recycled coarse aggregate (RCA) and recycled coarse aggregate concrete (RCAC) and test results are compared with the NCA and parent concrete made from NCA. Tests were carried out as per IS code and concrete was prepared using a two-stage mixing approach in the concrete mix design. M30 concrete mix of four RCAC samples was tested at 28 days of curing and in comparison with parent concrete, it is found that on an average compressive strength is decreased by 12.89% at 28 days curing. Adhered mortar increases the porosity of the recycled aggregate and forms a weak zone between aggregate surface and mortar. In addition, test results showed the defects in recycled aggregate and helped to identify the area where concentration is necessary to improve the quality of recycled aggregate using six sigma DMAIC methodology. Total of 12 defects were found in the process and raw material. Statistical analysis was used to evaluate the performance of all the mix made with RCA.

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On Properties of Recycled Coarse Aggregate from Repeatedly Recycling Waste Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.2185 ◽

2011 ◽

Vol 368-373 ◽

pp. 2185-2188

Author(s):

Ping Hua Zhu ◽

Xin Jie Wang ◽

Jin Cai Feng

Keyword(s):

Compressive Strength ◽

Coarse Aggregate ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Fine Aggregate ◽

Recycled Coarse Aggregate ◽

Coarse Aggregates ◽

Recycled Fine Aggregate ◽

Waste Concrete

The properties of recycled coarsee aggregates from repeatedly recycling waste concrete were determined. In this study, five series of concrete mixtures using coarse and fine natural aggregates were prepared, which have the same objective slump value from 35mm to 50mm and different compressive strengths ranging from 25MPa to 60 MPa. These five concretes were crushed, sieved, washed with water, hot treatmented at 300°C before they were used as recycled aggregates. After that, recycled aggregate concrete (RAC) was produced with an objectively compressive strength of 30MPa, in which the recycled coarse aggregate was used as 30%, 70% and 90% replacements of natural coarse aggregate and recycled fine aggregate as 10%, 20%, and 30% replacements of natural fine aggregate. After that, these recycled concretes were used as second recycled aggregates to produce RAC with the same objectively compressive strength of 30MPa. The physical properties of coarse aggregates including apparent density, water absorption, attached mortar content and crushing value were tested and their mineral characteristics were analyzed. The results showed that the quality of recycled coarse aggregates from twicely recycling waste concrete reached the requirements from structural concrete.

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Concrete produced with recycled aggregates

Revista IBRACON de Estruturas e Materiais ◽

10.1590/s1983-41952012000500006 ◽

2012 ◽

Vol 5 (5) ◽

pp. 692-701 ◽

Cited By ~ 2

Author(s):

J. J. L. Tenório ◽

P. C. C. Gomes ◽

C. C. Rodrigues ◽

T. F. F. de Alencar

Keyword(s):

Coarse Aggregate ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Hardened Concrete ◽

Specific Mass ◽

River Sand ◽

Recycled Coarse Aggregate ◽

Coarse Aggregates ◽

Natural Aggregates

This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC) for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW), which were divided into recycled sand (fine) and coarse aggregates. Besides this, a recycled coarse aggregate of a specific mass with a greater density was obtained by mixing the recycled aggregates of the CDW with the recycled aggregates of concrete wastes (CW). The concrete was produced in laboratory by combining three water-cement ratios, the ratios were used in agreement with NBR 6118 for structural concretes, with each recycled coarse aggregates and recycled sand or river sand, and the reference concrete was produced with natural aggregates. It was observed that recycled aggregates can be used in concrete with properties for structural concrete. In general, the use of recycled coarse aggregate in combination with recycled sand did not provide good results; but when the less porous was used, or the recycled coarse aggregate of a specific mass with a greater density, the properties of the concrete showed better results. Some RAC reached bigger strengths than the reference concrete.

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Effect of glass fiber and recycled aggregates on Geopolymer concrete

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/889/1/012038 ◽

2021 ◽

Vol 889 (1) ◽

pp. 012038

Author(s):

Shalika Mehta ◽

Mohit Bhandari

Keyword(s):

Flexural Strength ◽

Glass Fiber ◽

Coarse Aggregate ◽

Strength Properties ◽

Source Material ◽

Recycled Aggregates ◽

Geopolymer Concrete ◽

Coarse Aggregates ◽

Local Sources ◽

Class F Fly Ash

Abstract This study presents the effect of glass fiber and recycled aggregates on the strength properties of Geopolymer Concrete (GPC). The recycled aggregates were incorporated as a partial substitute for the natural coarse aggregates in the geopolymer concrete at 50%, 80%, and 100% by weight, and the results were compared to natural coarse aggregate. Class F fly ash is utilized as the source material for the production of Geopolymer and brought in from local sources. The effect of glass fiber (alkali resistant) with a length of 36 mm is also studied for the content ranging from 0.3, 1, 2, 3, and 3.5% based on the weight of the concrete. The flexural strength and compressive strength were compared at 7 days and 28 days for different cases. The results show that 1%, 1.5%, 2%, and 2.5% of glass fiber have exceeded the flexural strength of the geopolymer concrete by 20%.

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