Investigation of the Use of Recycled Concrete Aggregates Originating from a Single Ready-Mix Concrete Plant

The waste produced from ready-mixed concrete (RMC) industries poses an environmental challenge regarding recycling. Three different waste products form RMC plants were investigated for use as recycled aggregates in construction applications. Crushed hardened concrete from test specimens of at least 40 MPa compressive strength (HR) and crushed hardened concrete from returned concrete (CR) were tested for their suitability as concrete aggregates and then used as fine and coarse aggregate in new concrete mixtures. In addition, cement sludge fines (CSF) originating from the washing of concrete trucks were tested for their properties as filler for construction applications. Then, CSF was used at 10% and 20% replacement rates as a cement replacement for mortar production and as an additive for soil stabilization. The results show that, although there is some reduction in the properties of the resulting concrete, both HR and CR can be considered good-quality recycled aggregates, especially when the coarse fraction is used. Furthermore, HR performs considerably better than CR both as coarse and as fine aggregate. CSF seems to be a fine material with good properties as a filler, provided that it is properly crushed and sieved through a 75 μm sieve.

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Polymer Based Treatments Applied on Recycled Concrete Aggregates

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.687.514 ◽

2013 ◽

Vol 687 ◽

pp. 514-519 ◽

Cited By ~ 5

Author(s):

Valerie Spaeth ◽

Assia Djerbi Tegguer

Keyword(s):

Material Flow ◽

Recycled Concrete ◽

Recycled Aggregates ◽

Hardened Concrete ◽

Sustainable Material ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates

The recycling of concrete, bricks and masonry rubble as concrete aggregates is an important way to contribute to a sustainable material flow. However, there are still various uncertainties limiting the widespread use of recycled concrete aggregates (RCA). The fluctuations in the composition of grade recycled aggregates and their influence on the properties of fresh and hardened concrete are of particular concern regarding the use of RCA. So, the reuse of RCA is still limited. That’s why an efficient polymer based treatment is proposed in order to reuse RCA easier.

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Evaluation of Eco-Efficient Concretes Produced with Fly Ash and Uncarbonated Recycled Aggregates

Materials ◽

10.3390/ma14247499 ◽

2021 ◽

Vol 14 (24) ◽

pp. 7499

Author(s):

Miren Etxeberria

Keyword(s):

Fly Ash ◽

Recycled Concrete ◽

Recycled Aggregates ◽

Hardened Concrete ◽

Conventional Concrete ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Carbonation Resistance ◽

Chloride Resistance ◽

Natural Aggregates

The fabrication of conventional concrete, as well as remains from demolition, has a high environmental impact. This paper assessed the eco-efficiency of concrete made with uncarbonated recycled concrete aggregates (RCA) and fly ash (FA). Two concrete series were produced with an effective water/cement ratio of 0.50 (Series 1) and 0.40 (Series 2). In both series, concretes were produced using 0% and 50% of RCA with 0%, 25% and 50% FA. After analysing the compressive strength, and carbonation and chloride resistance of those concretes, their eco-efficiency based on the binder intensity and CO2-eq intensity was assessed. We found that the use of 50% uncarbonated RCA improved the properties of concretes produced with FA with respect to using natural aggregates. The concrete made of 25% FA plus RCA was considered the most eco-efficient based on the tests of compressive, carbonation and chloride properties with the values of 4.1 kg CO2 m−3 MPa−1, 76.3 kg CO2 m−3 mm−1 year0.5 and 0.079 kg CO2 m−3 C−1, respectively. The uncarbonated RCA improved carbonation resistance, and FA improved chloride resistance. It can be concluded that the use of 50% un-carbonated RCA combined with FA considerably enhanced the properties of hardened concrete and their eco-efficiency with respect to concretes produced with natural aggregates.

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Characterisation and Life Cycle Assessment of Pervious Concrete with Recycled Concrete Aggregates

Crystals ◽

10.3390/cryst11020209 ◽

2021 ◽

Vol 11 (2) ◽

pp. 209

Author(s):

Adilson C. Paula Junior ◽

Cláudia Jacinto ◽

Thaís M. Oliveira ◽

Antonio E. Polisseni ◽

Fabio M. Brum ◽

...

Keyword(s):

Environmental Performance ◽

Treatment Plant ◽

Recycled Concrete ◽

Pervious Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Positive Contribution ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates

The search for environmental preservation and conservation of natural resources gives rise to new concepts and viable technical solutions on the path to sustainable development. In this context, this study’s main objective is to analyse the influence of recycled concrete aggregates (RCAs) on the development of pervious concrete, whose use as a floor covering represents an excellent device to mitigate the urban soil sealing phenomena. For this, mechanical and hydraulic tests were carried out, in addition to microstructural analyses and the assessment of its environmental performance. The results obtained were compared to reference studies also involving the incorporation of recycled aggregates. A pilot-scale case study was conducted, involving a parking space lined with pervious concrete moulded “in situ”. In laboratory tests, permeability coefficients and mechanical strengths compatible with the literature and above the normative limit for light traffic were found. The case study demonstrated higher permeability than in the laboratory, but the flexural strength was lower, being indicated only for pedestrian traffic. The environmental assessment showed that the RCA represents a positive contribution to the environmental performance of pervious concrete. Still, attention should be given to the recycled aggregate transport distance between the concrete plant and the RCA treatment plant.

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Strength and Water Absorption of Sustainable Concrete Produced with Recycled Basaltic Concrete Aggregates and Powder

Sustainability ◽

10.3390/su13116277 ◽

2021 ◽

Vol 13 (11) ◽

pp. 6277

Author(s):

Ibrahim Sharaky ◽

Usama Issa ◽

Mamdooh Alwetaishi ◽

Ahmed Abdelhafiz ◽

Amal Shamseldin ◽

...

Keyword(s):

Water Absorption ◽

Edge Length ◽

Recycled Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Partial Substitution ◽

Small Reduction ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Sustainable Concrete

In this study, the recycled concrete aggregates and powder (RCA and RCP) prepared from basaltic concrete waste were used to replace the natural aggregate (NA) and cement, respectively. The NA (coarse and fine) was replaced by the recycled aggregates with five percentages (0%, 20%, 40%, 60% and 80%). Consequently, the cement was replaced by the RCP with four percentages (0%, 5%, 10% and 20%). Cubes with 100 mm edge length were prepared for all tests. The compressive and tensile strengths (fcu and ftu) and water absorption (WA) were investigated for all mixes at different ages. Partial substitution of NA with recycled aggregate reduced the compressive strength with different percentages depending on the type and source of recycled aggregate. After 28 days, the maximum reduction in fcu value was 9.8% and 9.4% for mixtures with coarse RCA and fine RCA (FRCA), respectively. After 56 days, the mixes with 40% FRCA reached almost the same fcu value as the control mix (M0, 99.5%). Consequently, the compressive strengths of the mixes with 10% RCA at 28 and 56 days were 99.3 and 95.2%, respectively, compared to those of M0. The mixes integrated FRCA and RCP showed higher tensile strengths than the M0 at 56 d with a very small reduction at 28 d (max = 3.4%). Moreover, the fcu and ftu values increased for the late test ages, while the WA decreased.

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Modulus and Strength of Concretes with Alternative Materials

Materials ◽

10.3390/ma13194378 ◽

2020 ◽

Vol 13 (19) ◽

pp. 4378

Author(s):

Ana Elisabete Paganelli Guimarães de Avila Jacintho ◽

Ivanny Soares Gomes Cavaliere ◽

Lia Lorena Pimentel ◽

Nádia Cazarim Silva Forti

Keyword(s):

Recycled Concrete ◽

Recycled Aggregates ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Model Code ◽

Alternative Materials ◽

Model Code 2010 ◽

The Difference ◽

Natural Aggregates ◽

Predicted Values

This paper presents a study with concretes produced with natural aggregates, recycled concrete aggregates (RCA) and waste porcelain aggregates (WPA). The study analyzed the influence of recycled aggregates in the mechanical properties of conventional concretes and evaluated the difference between measured and predicted values of elasticity modulus. The incorporation of WPA in concrete showed better mechanical results compared to the concretes produced with RCA. Measured elasticity moduli were lower than moduli predicted by NBR 6118:2014 and fib Model Code 2010, while measured results were greater than values predicted by Eurocode 2:2004 and ACI 318:2014, as expected, which indicated the safety of the latter two standards.

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Influence of the Crushing Process of Recycled Aggregates on Concrete Properties

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.634.151 ◽

2014 ◽

Vol 634 ◽

pp. 151-162 ◽

Cited By ~ 4

Author(s):

Diogo Pedro ◽

Jorge de Brito ◽

Luís Evangelista

Keyword(s):

Water Absorption ◽

Recycled Concrete ◽

Recycled Aggregates ◽

Efficient Production ◽

Capillary Water ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Carbonation Resistance ◽

Chloride Penetration Resistance ◽

Durability Performance

This work intends to evaluate the (mechanical and durability) performance of concrete made with coarse recycled concrete aggregates (CRCA) obtained using two crushing processes: primary crushing (PC) and primary plus secondary crushing (PSC). This analysis intends to select the most efficient production process of recycled aggregates (RA). The RA used here resulted from precast products (P), with strength classes of 20 MPa, 45 MPa and 65 MPa, and from laboratory-made concrete (L) with the same compressive strengths. The evaluation of concrete was made with the following tests: compressive strength; splitting tensile strength; modulus of elasticity; carbonation resistance; chloride penetration resistance; capillary water absorption; and water absorption by immersion. These findings contribute to a solid and innovative basis that allows the precasting industry to use without restrictions the waste it generates.

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Durability of Pavement Concretes Made with Recycled Concrete Aggregates

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2290-06 ◽

2012 ◽

Vol 2290 (1) ◽

pp. 44-51 ◽

Cited By ~ 7

Author(s):

Jitendra Jain ◽

Kho Pin Verian ◽

Jan Olek ◽

Nancy Whiting

Keyword(s):

Base Material ◽

Concrete Pavement ◽

Recycled Concrete ◽

Electrical Impedance Spectroscopy ◽

Concrete Pavements ◽

Chloride Permeability ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Air Content ◽

Concrete Mixtures

There is a growing trend to replace the traditional ingredients of concrete pavement mixtures with more sustainable materials from a perspective of both the cost of raw materials and the carbon dioxide footprint. The availability of quality natural aggregates, which make up about 70% to 80% of concrete (by volume), is becoming more limited because of environmental restrictions on quarrying operations and longer hauling distances. The other major concern is disposal of old concrete pavements, which unless used as fill or base material for construction of new roadways, will have to be placed in the landfills. In this study, recycled concrete aggregates (RCA) obtained from crushing old concrete pavement were used as coarse aggregates at 0%, 30%, 50%, and 100% replacement levels (by mass) for natural virgin aggregates (NVA). Concrete mixtures were designed and produced to meet the concrete pavement requirements for air content, slump, and flexural strength stipulated by the Indiana Department of Transportation. All concrete mixtures were produced with 18.5% to 20.0% of the cement replaced (by mass) with ASTM C618 Class C fly ash. The physical and mechanical testing involved evaluation of slump, air content, and development of both flexural and compressive strengths. In addition, durability was assessed with the freeze–thaw test, scaling test, rapid chloride permeability (RCP) test, and non–steady state migration test. The most advantageous dosages for replacing NVA with RCA for concrete pavements were found to be 50%, on the basis of fresh concrete properties and the results of strength and durability tests. The applicability of electrical impedance spectroscopy for quick performance appraisal is presented on the basis of the experimental relationship between the RCP charge and bulk resistance of concrete.

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Durable Performance of Recycled Concrete Using Coarse and Fine Recycled Concrete Aggregates in Air Environment

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.261-263.446 ◽

2011 ◽

Vol 261-263 ◽

pp. 446-449 ◽

Cited By ~ 2

Author(s):

Ping Hua Zhu ◽

Xin Jie Wang ◽

Jin Cai Feng

Keyword(s):

Recycled Concrete ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Structural Concrete ◽

Aggregate Concrete ◽

Cube Strength ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Natural Aggregate ◽

Concrete Mixtures

The influence of synchronous use of coarse and fine recycled concrete aggregates on durable performance of recycled aggregate concrete (RAC) in air environment were determined. In this study, three series of concrete mixtures were prepared, in which the coarse recycled aggregate was used as 0%, 30%, 60% and 90% replacements of coarse natural aggregate and fine recycled aggregate as 0%, 10%, 20%, and 30% replacements of fine natural aggregate. Meanwhile, fly ash and slag were used as 15%, 25%, 35% and 45% replacements of cement, respectively. The carbonation depths, compressive cube strength, workability of RACs were tested. The experimental results showed that RAC with synchronous use of coarse and fine recycled concrete aggregates had satisfactory durable performance. When RAC was used as structural concrete in air environment, the optimum synchronous replacements are 60% for coarse recycled aggregate and 20% for fine recycled aggregate.

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Quality Evaluation System for Description of Recycled Concrete Aggregates and Verification of its Functionality

Materials Science Forum ◽

10.4028/www.scientific.net/msf.902.14 ◽

2017 ◽

Vol 902 ◽

pp. 14-19 ◽

Cited By ~ 1

Author(s):

Iveta Nováková ◽

Iveta Hájková

Keyword(s):

Evaluation System ◽

Quality Evaluation ◽

Recycled Concrete ◽

Demolition Waste ◽

Concrete Aggregates ◽

Recycled Concrete Aggregates ◽

Concrete Mixtures ◽

Natural Aggregates ◽

Set Up ◽

Quality Evaluation System

Article presents quality evaluation system for description of recycled concrete aggregates (RCA), verification of RCA properties and subsequent application in to concrete mixtures as a partial or total replacement of natural aggregates (NA). Modernization and rehabilitation of constructions is accompanied by creation of demolition waste from old buildings and structures. The necessity of recycling is unavoidable, because volume of construction and demolition waste (C&DW) is increasing and the landfills are reaching their maximum capacity. Nowadays, there are numerous research teams focused on analysis of characteristics and application of RCA into new concrete as a replacement of NA. Test samples of RCA have always different source, grain composition and other physical and mechanical properties, which are variously described in each different paper. Up to now, there is no any uniform quality evaluation system for description of recycled concrete aggregates, which can easily describe their source and assumed properties. Our aim is to set up rules for description of RCA and simplify the evaluation of properties of various RCA. Qualification system will be applied on three different samples of RCA and verified by the selected properties tests. Tested samples of RCA will be than used as a replacement of natural aggregates in concrete mixtures. The replacement amount was set up on 20%, 40% and 100% according to the reviewed literature, to have a comparable replacement amount and valuable results for discussion. The results of RCA testing and testing of concrete with partial and total replacement of NA showed that the evaluation system is working properly. It can be concluded, that accuracy of the quality evaluation system for description of recycled concrete aggregates is sufficient, but more tests on RCA should be done to prove all connections in between description of RCA and their properties.

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Long-term performance of sustainable pavements using ternary blended concrete with recycled aggregates

10.21079/11681/40780 ◽

2021 ◽

Author(s):

Gilson Lomboy ◽

Douglas Cleary ◽

Seth Wagner ◽

Yusef Mehta ◽

Danielle Kennedy ◽

...

Keyword(s):

Portland Cement ◽

Cementitious Materials ◽

Recycled Concrete ◽

Supplementary Cementitious Materials ◽

Recycled Aggregates ◽

Concrete Aggregate ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Concrete Aggregates ◽

Concrete Mixtures

Dwindling supplies of natural concrete aggregates, the cost of landfilling construction waste, and interest in sustainable design have increased the demand for recycled concrete aggregates (RCA) in new portland cement concrete mixtures. RCA repurposes waste material to provide useful ingredients for new construction applications. However, RCA can reduce the performance of the concrete. This study investigated the effectiveness of ternary blended binders, mixtures containing portland cement and two different supplementary cementitious materials, at mitigating performance losses of concrete mixtures with RCA materials. Concrete mixtures with different ternary binder combinations were batched with four recycled concrete aggregate materials. For the materials used, the study found that a blend of portland cement, Class C fly ash, and blast furnace slag produced the highest strength of ternary binder. At 50% replacement of virgin aggregates and ternary blended binder, some specimens showed comparable mechanical performance to a control mix of only portland cement as a binder and no RCA substitution. This study demonstrates that even at 50% RCA replacement, using the appropriate ternary binder can create a concrete mixture that performs similarly to a plain portland cement concrete without RCA, with the added benefit of being environmentally beneficial.

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