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New Concrete with Recycled Aggregates fromLeftover Concrete

 ARTICLE · APRIL 2015

DOI: 10.4028/www.scientific.net/AMM.754-755.389

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Universitatea Tehnica Cluj-Napoca

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Gheorghe Asachi Technical University of Iasi

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Universiti Malaysia Perlis

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New Concrete with Recycled Aggregates from Leftover Concrete

Ofelia Corbu1,a, Attila Puskás 1,b , Andrei Victor  Sandu 2,4,c , Adrian Ioani 1,d, Kamarudin Hussin3,4,e and Ioan Gabriel Sandu2,f

1Faculty of Civil Engineering, Technical University of Cluj-Napoca, Romania

2Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, Blvd.D. Mangeron 41, 700050, Iasi, Romania

3Faculty of Engineering Technology, Universiti Malaysia Perlis (UniMAP), 01007, P.O Box 77, D/APejabat Pos Besar, Kangar, Perlis, Malaysia

4Center of Excellence Geopolymer & Green Technology (CEGeoGTech), School of MaterialsEngineering, Universiti Malaysia Perlis, 01000 Kangar, Perlis, Malaysia

aofelia.corbu@staff.utcluj.ro, battila.puskas@dst.utcluj.ro, csav@tuiasi.ro,dioaniam@yahoo.com, ekamarudin@unimap.edu.my, f gisandu@yahoo.com

Keywords: Leftover concrete aggregate, concrete waste, recycled aggregates, newaggregate/concrete

Abstract. We live in an era where people should be more aware of pollution and its consequences.

The present paper reveals a way protecting the environment while producing high quality concrete.

What make this type of concrete environmentally friendly are the recycled aggregates in the

concrete composition amongst with eliminating the ecological impact by saving large amounts of

natural aggregates resources. Recycling concrete comes with many other advantages that lead to

waste reduction, economy in waste transportation and storage taxes, which are becoming

increasingly expensive. This research is based on mix design and experimental tests carried out on

C20/25 strength class concrete with uncontaminated leftover concrete aggregates (LCAgg). It

reveals favorable results in order to militate for recycled concrete aggregate uses in regular concrete

strength classes respectively for common structural elements, mainly for slabs. River sand (0/4 mm)and coarse aggregates (4/8 mm and 8/16 mm): natural sources or recycled concrete type -

alternatively used in several mixes- were utilized in concrete mixes.

Introduction

Since 1945 several studies related to recycled aggregate concrete resulting from construction

and demolition waste were performed in Romania by researchers Steopoe [1,2], institutes like

Technical University of Civil Engineering Bucharest and National Research & Development

Institute for Building, Urban Planning and Sustainable Spatial Development “URBAN-INCERC”,Cluj-Napoca Branch [3], have been undertaken researches on usual and lightweight concrete made

 by recycled concrete aggregates, while at the Technical University of Cluj-Napoca, concrete roadsmixes with waste glass or recycled concrete aggregates was tested [4, 5].

Concrete recycling process [6] was carried out in several countries, sources and requirements

for recycled aggregate concrete are shown in Table 1 [7]. Many researchers have studied the use of

wastes in composite and concrete structures [8-11], with focus on the (a) percentages are of coarse

aggregate fraction - unless otherwise stated, (b) assuming leftover concrete aggregate separated by

strength class; to (c) coarse and fine fraction; obtained from ( NS) non-structural concrete; resulting

( RCA)  recycled concrete aggregate (Predominantly from demolition waste concrete) and ( LCAgg) 

leftover concrete aggregate (Aggregate processed from hardened leftover concrete of known

composition that has not been in use and has not been contaminated in storage)  –   or, generally

speaking ( RA)  recycled aggregate (Predominantly demolition waste including concrete, masonry

and asphalt), with (NR) no restriction . The mandatory elements for the new approach of the construction domain are the energy and

natural resources saving tendency and the large scale use of waste, respectively. [12, 13].

 Applied Mechanics and Materials Vols. 754-755 (2015) pp 389-394 Submitted: 06.01.2015© (2015) Trans Tech Publications, Switzerland Accepted: 06.01.2015doi:10.4028/www.scientific.net/AMM.754-755.389

 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP,www.ttp.net. (ID: 86.124.144.26-09/02/15,12:35:51)

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Table 1. Requirements for recycled aggregate concrete in different countries [7] 

Country/

Organisation

Recycled

Aggregate

Type/ Name/

Classification

Agg

Genre

Maximum

RCA

Substi-

tution(a) 

Maximum Recycled

Aggregate Concrete

28 Day

Cylinder Strength

Other

Restrictions

United

Kingdom

RCA RCA

 NR 40 MPa RCA and LCAgg. No chlor. exp. No freeze

thaw.20%

Designated

concrete

20 to 40 MPa

LCAgg LCAgg NR NR -

RA RA - 16 MPa Only mild exposure.

AustraliaClass 1A RCA 30% 40 MPa -

Class 1B RCA 100% 25 MPa -

USA LCA LCAgg

100%   20 MPa

-25% 50 MPa

60% c  NS Concrete

RILEM

CAC Type I RA 100% 16MPa Masonry Aggregate.

Exposure restrictions.CAC Type II RCA 100% 50MPa

CAC Type III RCA 20% NR

Korea - RCA30% 27 MPa

-30% c   21 MPa

GermanyType 1

RCA35% 25 MPa In dry or low humidity

environments.Type 2 25% 30 MPa

PortugalARB1

RCA25% 35 MPa

-ARB2 20% 40 MPa

Hong Kong - RCA20% ≤35 MPa 

-100% 20 MPa NS Conc.

Concrete remains the most widely used building material, having the advantage of its

resources (traditional or innovative) as well as the long service life of concrete structures. Concrete

construction are highly promoted also due to the benefits of sustainability, thermal capacity,

ensuring natural disasters facing areas, the potential use of waste and by-products [14].

The environmental impact and the huge consumption of natural aggregates are substantially

reduced through the use of recycled aggregates [12, 15].

Realization of new concrete with recycled aggregates

Concrete mix: In the present study, mix design of concrete composition was done after a

careful analysis of aggregates properties, especially the used recycled aggregates characteristics[16], and then on an algorithm based adaptation of a suitable proportions, thus the mix compositions

meet the requirements of romanian regulation in force for execution of concrete structures (NE

012/2007) [17]. Special attention is given to the aggregate, representing around 70% of the concrete

mix composition and it has been also the variable compound of the mixes. 

The first step in this research was the control concrete mix design (CC), made with natural

aggregates, currently used in concrete mixtures After that, it was developed three more alternative

mixes through the partial or total replacement of natural crushed aggregates with recycled crushed

ones (4/8 mm and 8/16 mm types). Natural sand, 0/4 mm, was maintained in each mixture to sustain

a better concrete workability, due to the round shape of the natural aggregate particles.

The following aggregates proportions (volume percentages) were kept for all mixtures, which

came into the total grading curve calculation:- 48.0 % - for 0/4 mm,

- 19.2 % - for 4/8 mm,

- 32.8 % - for 8/16mm

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Also the same water/cement ratio was precisely kept for all mixes in order to observe the

concrete workability variation according to the concrete mixes compounds changes. The mixtures

constituent proportions reported to the cement amount, considered as the unit, are presented in table

2.

Table 2. C20/25 concrete strength class constituents [kg/m³] 

Cement 0/4 mm 4/8 mm 8/16 mm Water1 2.68 1.07 1.83 0.55

Four concrete mixtures were designed and tested in this study, using different quantity and

grade of recycled aggregates:

1.  Control Concrete (CC) with natural aggregate (NA)

2.  Concrete with Leftover Concrete Aggregate (CLCRAgg4/8) with recycled aggregate (RA) 4/8

mm

3.  Concrete with Leftover Concrete Aggregate (CLCRAgg8/16) with recycled aggregate (RA)

8/16 mm

4.  Concrete with Leftover Concrete Aggregate (CLCRAgg4/8;8/16) with recycled aggregate (RA)

4/8 and 8/16 mmMaterials used in the concrete mixtures are conventional ones, procured from local producers

and correspond to the national and European standards.

Recycled aggregate are resulting from hardened leftover concrete of known composition that

has not been in use and nor contaminated in storage (LCAgg), representing lefrover of industrial

 production of a large local concrete element producer. The company pays high fees for removal,

transportation and disposal of this kind of waste to landfill as inert solid waste.

The type of cement used in the composition of concrete is CEM I 42.5N, based on SR EN

197-1 2011 [18], cement having normal (usual) initial resistance. The used aggregates are natural

sand (0/4 mm) as fine aggregate, crushed river aggregate and recycled aggregate processed from

hardened leftover concrete. The concrete waste was crushed, sieved and sorted in several fraction,

resulting recycled concrete aggregate (4/8 mm and 8/16 mm) same size as crushed, natural

aggregate, in order to be able to substitute it in new concrete. The new concrete mixes are designed

to meet the requirements of concrete norm ( NE 012: 2007)  [17]. In this context were chosen the

grading limits for the total aggregates, for C20/25 concrete strength class made with 16 mm

maximum aggregate size (SR EN 933-1: 2012)[20].

The total aggregate limits came into the total grading curve calculation presented in (Fig.1)

Fig. 1. Similarity of the total grading curves with the same percentages for (NA) & (RA)

In order to produce high quality concrete the recycled aggregate composition should be

 properly evaluated [15]. Several studies demonstrated that 4/8 mm recycled aggregate fraction hasthe largest amount of adhered mortar layer, which means that the aggregate size has a high effect on

water absorption and concrete resistance [20, 21]. The measured water absorption of 4/8 mm

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recycled aggregate fraction is 6%, while the 8/16 mm recycled aggregate fraction has 5% measured

water absorption. 

The water used for the concrete mix came from the public water supply pipe, as mentioned in

SR EN 1008: 2003 [22]. The used admixture  belongs to the superplasticizer class based on

 polycarboxylates, one of the newest types of additives. The used admixture is MasterGlenium SKY

500 BASF for ready-mix concrete, in accordance with SR EN 934-2:2009 [23].

Characteristics of the mixtures with recycled aggregates

Control concrete (CC) mixture design fulfills the Romanian standard requirements for

 preliminary mixtures, where the acceptable value of mean compressive strength is obtained by

adding a value ranging from 6 to 12 units (MPa) to the characteristic strength f ck  corresponding to

each concrete strength class (f c = f ck  + (6 ÷ 12) (MPa)), according to National [17] and European

norms [23] (Fig. 2).

 Establishing concrete classes

25.2 31 35.5 37  

37.2 3943.5 45.5

0

10

20

30

40

50

CC CLCR

 Agg4/8

CLCR

 Agg8/16 

 LCRAgg 

4/8;8/16 

  c  m  c  u   b  e   2   8

   [   M   P  a   ]

 fck cube

 fcm cube28

C20/25

C25/30

C25/30  C30/37

 Fig. 2. Compressive strength and strength classes of concrete mixtures

Table 3. Characteristics of fresh and hardened concreteCharacteristics  UM    Reference Testing methods   Mixes 

level   CC   C  LCRAgg

4/8 

C  LCRAgg

8/16  

C  LCRAgg

4/8; 8/16  

Consistency (S3) mm 80÷150  SR EN 12350-

2:2009110 65 33 29

Temperature (T) C 5÷30  NE 012-1:2007 19 22 21 22

Apparent density (ρ) offresh concrete

Kg/m3  2365+40

SR EN 12350-

6:20022370 2376 2404 2372

Compressive strength

(fcmcub)MPa Min 80

SR EN 12390-

3:200237.2 39 43.5 45.5

Elasticity modulus

(Ecm)GPa > 30  EUROCODE 2 32.9 33.5 34.7 34.9

Apparent density (ρ) ofhardened concrete

Kg/m3

2400SR EN 12390-

7:20022351 2354 2355 2352

Concrete workability Tests performed on fresh concrete mixtures show a decrease of slumpvalues, for the three recycled aggregate concrete mixes in comparison with the control concrete

mix. CC mixture workability was established as S3 slump class, admissible values ranging from

100 mm to 150 mm. 

Compressive strength tests results show a sensitive increase of CLCR Agg 4/8, CLCR Agg 8/16 

and CLCR Agg 4/8; 8/16 mixtures value with respect to the CC mixture compressive property. These

results contradict other relevant studies upon the matter, that imply decrease of compressive

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 performances of recycled concrete aggregate mixes [25-27]. A possible explanation for the increase

of compressive strength of studied mixtures could derive from the good quality of raw materials,

respectively increased performance of the recycled aggregates processed from a hardened leftover

concrete (good resistance to fragmentation and good resistance to wear).

Modulus of elasticity values, determined for each concrete mixtures (CC, CLCR Agg 4/8,

CLCR Agg 8/16 and CLCR Agg 4/8; 8/16) presented in Table 3 satisfy the requirements of European norms[28].

Conclusions

The present study shows the mix design of control concrete with natural aggregates (NA) on

C20/25 (CC) strength class concrete, followed by design of other three mixes, adjusted to (CC) by

alternatively substituting the same amount of NA with RA from leftover concrete (LCAgg) of

known historical origin, crushed and sorted to (NA) size. It has been proven that the new ecological

concrete (NEC) can be achieved through using of recycled aggregates (RA) with greater crushing

resistance than of the (NA). Quality of (RA) obtained from scrap concrete is better of than those

from demolition debris and decommissioning. Characteristics of the (NEC) can be easily foreseenfor concrete waste of known origin. In the case (RA) source of controlled quality results might

 present even higher compressive strength, as happened also for the studied mixes: the higher the

crushed concrete class is the more increased mechanical properties can be obtained for the mix. Due

to the higher water absorption rate of the (RA) the concrete workability can be optimized by adding

additional water (increased by 10% to 20%) when using recycled aggregates, thus the increase of

the water / cement ratio should lead to decrease of concrete strength. Even if the water absorption of

(RA) is higher, the absorbed water can sustain the hydration for a longer period, with benefits to the

increasing the compressive strength of (NEC). The (NEC) mixes obtained with use of more than

19% (RA) show more than satisfactory characteristics.

The presented studies are pointing out that the recycled aggregates are representing valuable

resource as prime material in the production of the ecological concrete. The obtained results mayencourage companies who possess leftover concrete to involve in the new business oportunities.

Internal waste management of the companies made in a rigorous way might bring great benefits

avoiding the evacuation expenses.

Acknowledgment

This paper was supported by the Post-Doctoral Programme POSDRU/159/1.5/S/137516, project co-

funded from European Social Fund through the Human Resources Sectorial Operational Program

2007-2013.

References

[1] A. Steopoe, Concrete debris, Volume 1, Bucharest, p. 60, 1945.[2] A. Steopoe, The use of materials in construction debris, Bucharest, 1946.[3] H. Szilagyi, A. Mircea, Z. Kiss „The Use of Waste Materials and By-Products in Lightweight

Concrete”, Global Construction Congress: Ultimate Concrete Opportunities, Dundee,Scotland, 5-7 July 2005, Thomas Telford Ltd, London, ISBN 0 7277 3401 6, pp. 261-368.

[4] O. Corbu, N. Chira, H. Szilagyi, H. Constantinescu, 13th SGEM GeoConference on Nano, BioAnd Green  –  Technologies For A Sustainable Future, SGEM2013 Conference Proceedings,(2013) 411 - 418.

[5] O. Corbu, H. Szilagyi, A. Puskas, A. Popovici, C. Baera, L. Moga, Recycling and wasterecovery in the construction field, Proceedings of the 14th International MultidisciplinaryScientific GeoConference & EXPO-SGEM, Albena, Bulgaria (2014), 259-265,

[6] C. Iacoboaea, Reciclarea deșeurilor din construcții și demolări - o necesitate? Volume 12, TheRomanian Economic Journal, Bucharest, i:33, (2009) 141-160.

[7] Goncalves & Brito Recycled Aggregate Concrete (RAC)  –   comparative analysis of existingspecifications, Magazine of Concrete Research, 62, 5 (2010) 339-346,

Applied Mechanics and Materials Vols. 754-755 393

8/20/2019 New Concrete With Recycled Aggregates

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[8] Z. Yahya, M.M.A. Abdullah, K. Hussin, K.N. Ismail, A.V. Sandu, P. Vizureanu, R. AbdRazak, Chemical and Physical Characterization of Boiler Ash from Palm Oil Industry Wastefor Geopolymer Composite, Revista de Chimie (Bucharest), 64, 12 (2013) 1408-1412.

[9] A.M.M. Al Bakri, H. Kamarudin, I.K. Nizar, A.V. Sandu, M. Binhussain, Y. Zarina, A.R.Rafiza, Design, Processing and Characterization of Fly Ash-Based Geopolymers for

Lightweight Concrete Application, Revista de Chimie (Bucharest), 64, 4 (2013) 382-387.[10] A.M. Izzat, A.M.M. Al Bakri, H. Kamarudin, L.M. Moga, G.C.M. Ruzaidi, M.T.M. Faheem,A.V. Sandu, Microstructural Analysis of Geopolymer and Ordinary Portland Cement MortarExposed to Sulfuric Acid, Materiale Plastice (Bucharest), 50, 3 (2013) 171-174.

[11] V.A. Ceclan, P. Bere, M. Borzan, S. Grozav, C. Borzan, Development of EnvironmentalTechnology for Carbon Fibre Reinforced Materials Recycling, Materiale Plastice (Bucharest),50, 2 (2013) 79-93.

[12] O. Corbu, M. Popa, H. Szilagyi, A. Puskas., Energy Economy in obtaining high performanceconcrete, Conference Modern Science and Energy, 29th Edition, (2010), 343-354.

[13] O. Corbu, H. Szilagyi, A. Puskas., Waste recycling and their use in construction industry,Conference Modern Science and Energy, 32nd Edition, (2013), 74-81

[14] ***, Guidelines on the management of construction and demolition waste /Ghid privind

gestionarea deşeurilor din construcţii şi demolări, Sibiu, Romania (2011) [15] Y.H. Lin, Y.Y. Tyan, T.P. Chang, C.Y. Chang, Properties of high performance concrete with

recycled aggregates, Cement and Concrete Research, 36 (2006) 943 – 950[16] I. B. Topcu and N. Fuat, Using waste concrete as aggregate, Cement and Concrete Research,

25, 7 (1995) 1385-1390[17]  ***, NE 012-1/2007, Code of Practice for execution of concrete, reinforced concrete and

 prestressed concrete. Part 1: Concrete Production[18] ***, SR EN 197-1:2011, Cement composition.[19] ***, SR EN 933-1:2012, Aggregates for concrete.[20] S.R. Yadav, S. R. Pathak,, Use of recycled concrete aggregate in making concrete- an

overview, 34th Conference on our world in concrete & structures: 16  –   18 August (2009),

Singapore[21] W. Sami, S. Tabsh, A. Akmal, Influence of recycled concrete aggregates on strength properties

of concrete, Construction and Building Materials, 23 (2009) 1163 – 1167[22]  ***, SR EN 1008:2003, Mixing water for concrete. Specification for sampling, testing and

assessing the suitability of water, including water recovered from processes in the concreteindustry, as mixing water for concrete.

[23]  ***, SR EN 934-2:2009, Admixtures for concrete, mortar and grout, Concrete admixtures.Definitions, requirements, conformity, marking and labelling.

[24] ***, FIB Bulletin, Constitutive Modeling of High Strength/High Performance Concrete.Bulletin 42, CEB-FIB, France, (2008).

 

[25] S. Frondistou-Yannas, Waste Concrete as aggregate for new concrete, AC1 Journal, Proc., Vol.

74, 8, (1977) 373-376.[26] Hansen, T.D. and Narud, H.,Strength of recycled concrete made from crushed concrete coarseaggregate, ACI, Concrete International, Design and Construction, Feb. 1983, pp. 79-83.

[27] F.T. Olorunsogoa, N. Padayacheeb, Performance of recycled aggregate concrete monitored bydurability indexes, Cement and Concrete Research, 32 (2002) 179 – 185

[28] ***, Eurocod 2 –  SR EN 1992-1-1:2004: Design of Concrete Structures.

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