re

is3 Ma

Durability

e (frcroccred pe wace,bots. Tht. Th

concrete and the intrinsic properties of the new aggregate. Use of this waste as a construction material

eruk asical,ortenis. Duraenedzationequiremintend

in pores and their interaction with pore walls.At this time, in response to concerns about sustainability

(Blengini and Garbarino, 2010), research is underway on thepossibility of reusing different kinds of industrial waste (such asconstruction and demolitionwaste, tyres and ceramics) in concretemanufacture, thereby preserving the landscape by reducing theneed to quarry natural aggregate. According to National AssociationAggregate (ANEFA, 2011) data, 259 million tonnes of aggregatewere quarried in Spain in 2010.

List of abbreviations: EHE-08, Spanish code on structural concrete; C&DW,Construction and demolition waste; ITZ, Interfacial transition zone; RC, Referenceconcrete; CC-20, Concrete containing 20% recycled aggregate; CC-25, Concretecontaining 25% recycled aggregate; EITZ, Elastic modulus of the interface transitionzone; ecrack, Mean widths of concrete cracks; emax, Maximum widths of concretecracks.* Corresponding author. Tel.: 34 913020440x215; fax: 34 913020700.

Contents lists available at

Journal of Clean

journal homepage: www.els

Journal of Cleaner Production 40 (2013) 151e160E-mail address: cemedmart@yahoo.es (C. Medina).signicant loss of utility or excessive maintenance.Freeze-thaw action, as one of the major causes of concrete

deterioration in cold climates (Liu et al., 2011), must be taken intoconsideration in structural design. In Spain, further to Chapter II ofthe Code on Structural Concretee EHE-08 (Permanent commissionof the concrete, 2008), presently in effect all elements located infrequent contact with water, or areas with an average relativeenvironmental humidity over 75%, and which have an annual

governing frost damage for several decades and has consistentlyfound the generation of internal stress to be involved. According toWardeh et al. (2011), Snchez de Rojas et al. (2011) and Vegas et al.(2009), such stress is the result, briey, of: a) hydraulic pressuredue to ice formation, with a 9% expansion in volume; b) osmoticpressure generated in the pore system by the movement of liquidwater towards pores containing ice to restore thermodynamicequilibrium; and c) the pressure induced by the growth of crystals1. Introduction

Concrete structures (Kosior-Kazbcontinually exposed to attack by phyagents that may cause rapid decay, shraising maintenance and repair costimportant properties of materials, is d(European Committee for Standardidurable structure shall meet the rstrength and stability throughout its0959-6526/$ e see front matter 2012 Elsevier Ltd.http://dx.doi.org/10.1016/j.jclepro.2012.08.042nd Jezierski, 2004) arechemical and biologicalng their service life andbility, one of the mostin Eurocode EN 1992-2, 2010a) as follows: Aents of serviceability,

ed working life, without

probability of over 50% of reaching temperatures below 5 C atleast once a year are liable to freeze-thaw damage. Such damageconsists primarily (Hanjari et al., 2011; Harrison et al., 2001) ofmicro- or macro-cracking and surface scaling, which favourspenetration by aggressive external agents (such as sulphates andchlorides) and consequently corrosion.

Surface scaling or aking is regarded by some authors (Shi et al.,2010) as the main cause of decay and is directly related to concretequality.

The scientic community has been studying the mechanismsMicrostructure damages perspective of sustainable development. 2012 Elsevier Ltd. All rights reserved.Recycled concrete would yield substantial technical, economic and environmental benets, in particular from theFreeze-thaw durability of recycled conc

Csar Medina*, Mara Isabel Snchez de Rojas, MoEduardo Torroja Institute for Construction Science e CSIC, C/Serrano Galvache, 4, 2803

a r t i c l e i n f o

Article history:Received 28 May 2012Received in revised form24 August 2012Accepted 30 August 2012Available online 13 September 2012

Keywords:Ceramic aggregateFreeze-thaw

a b s t r a c t

Abrupt temperature changinasmuch as it induces mithe material, moreover inreducing its durability andurability of concrete madanalysing the scaled surfmaximum crack widths inafter 56 freeze-thaw cyclerecycled aggregate contenAll rights reserved.te containing ceramic aggregate

s Frasdrid, Spain

eeze-thaw cycles) is one of the most damaging actions affecting concrete,racking. The formation of this crack reduces the mechanical behaviour ofase the penetration of aggressive substances into the concrete matrix,ossibly leading to structural collapse. The present study explored theith aggregate containing 20e25% ceramic sanitary ware industry waste,exploring aggregate/paste de-bonding and measuring the mean and

h the paste and at the interfacial transition zone between paste-aggregatee ndings showed that concrete freeze-thaw resistance rose with risingis better performance was due to the high mechanical quality of recycled

SciVerse ScienceDirect

er Production

evier .com/locate/ jc lepro

code EHE-08.

2.1.4. CementThe cement used in all the concrete mixtures was Portland

cement CEM I 52.5 R, whose chemical composition is given inTable 3.

2.2. Methods

2.2.1. Mixtures composition of concretesThree types of concretes were prepared for this study: one

reference concrete (RC) and two recycled concretes, CC-20 and CC-25, in which 20 or 25 vol. %, respectively, of the natural coarseaggregate was replaced with recycled ceramic sanitary ware.

The La Pea dosage method (Fernndez, 2007) was used indesign and batching. The design parameters were: characteristicstrength, of 30 MPa; maximum aggregate size (20 mm); andconsistency, soft. The batching details are given in Table 4.

Thew/c ratio and cement content in all concretes complied withSpanish Code on Structural Concrete (EHE-08) specications onmaximum w/c ratio (0.55) and minimum cement content

0.63 0.45 0.30

nerThe European ceramic sanitary ware industry produces 0.5Mt ofthese items yearly (Commission, 2007), 10% of which are rejecteddue to dimensional or ring aws. This fraction of rejects is notreused in the production process, but shipped directly to landlls,posing technical as well as environmental problems.

The research conducted to date has focused on assessing theeffect of the partial replacement of natural aggregate with differenttypes of waste on the physical and mechanical properties andpermeability of the resulting concrete. Internationally, the shortnumber of papers published on the effect of recycled aggregate onfreeze-thaw resistance have addressed: construction and demoli-tion waste (C&DW) (Abbas et al., 2009; Salem et al., 2003); marble(Gencel et al., 2012); tyres (Richardson et al., 2012) and ceramicmaterials (Jankovic et al., 2010). The present study pioneersresearch on the resistance to this action in recycled concrete con-taining sanitary ware industry waste, an area unexplored to date.

The objective pursued was to analyse the effect of the partialreplacement (20e25%) of coarse aggregate with recycled ceramicware waste on the durability of concrete exposed to freeze-thawcycles. To that end, microstructural analyses were conducted toassess the scaled particles, de-bonding at the aggregate/pasteinterfacial transition zone (ITZ) and the degree of microcracking(mean and maximum width at the ITZ and in the paste) after 56cycles.

2. Materials and methods

2.1. Materials

2.1.1. Natural aggregatesThe natural aggregate used can be sub-divided into two cate-

gories: the coarse fraction (gravel), 4/20 mm in size and the nefraction (sand), with grains under 4 mm. Table 1 shows the proleof the gap-graded gravel.

Fig. 1 lists the chemical composition of the gravel, whose maincomponent, SiO2, accounted for 97 wt% of the total. The minorityoxides were Al2O3 and Fe2O3.

Further to the physical, chemical, mechanical and thermalproperties given in Table 2, these aggregates were European Stan-dard EN 12620-compliant (European Committee forStandardization, 2009).

2.1.2. Recycled ceramic aggregateThe recycled aggregate, supplied by a ceramic sanitary ware

factory, was crushed with a jaw crusher and sieved to obtain the 4/12.5 mm fraction (Table 1). This waste had two visually distin-guishable sides, depicted in Fig. 2: the glazed or outer side of theoriginal sanitary ware, representing less than 2% of the total waste,and the unglazed or inner side of these products.

On the grounds of its chemical composition as determined by X-ray uorescence (XRF) and shown in Fig. 1, this ceramic waste (totalceramic aggregate) was similar to other ceramic materials used inconstruction (Snchez de Rojas et al., 2007). The inner side con-sisted primarily of SiO2, Al2O3 and Fe2O3, which together totalled93.81% of the material, whilst on the outer side these compoundsaccounted for only 68.24%, with zircon (ZrO2) comprising 12.62%and calcium oxide (CaO) 11.80%. Alkalis (MgO, NaO and K2O) werealso found as minority components on both sides.

The physical, chemical, mechanical and thermal properties ofthe recycled aggregate (Table 2) were compliant with both Euro-pean Standard EN 12620 and Spanish Code Structural Concrete(EHE-08).

As Table 2 shows, the gravel was denser than the ceramicaggregate, which had a greater pore volume. The new aggregate,

C. Medina et al. / Journal of Clea152with a pore volume similar to the value observed for ceramicelectrical insulation, was 2.4 times more water-absorbent than thenatural material.

The akiness index was eight times higher in the recycledceramic aggregate than in gravel, primarily as a result of its outermorphology, in turn due to the original shape of the waste and thecrushing procedure.

Another important property in aggregates is their Los Angelescoefcient. The recycled sanitary ware aggregate was 39% morefragmentation resistant than gravel. Such improved performancewas also reported by Debieb and Kenai (2008), who observed thatred clay block exhibited greater resistance towear (31.6 wt%) thannatural aggregate (36.3 wt%).

Finally, the ceramic aggregate contained no organic materialthat would alter concrete setting and hardening rates nor did itexhibit alkali-aggregate reactivity, according to the petrographicstudy conducted.

2.1.3. Batching waterThe quality of the mixing water can affect concrete setting time

and strength development, as well as corrosion protection forreinforcement. Thewater used here conformed to the specicationslaid down in chapter VI Materials in Spanish structural concrete

0.4 0.42 0.270.315 0.40 0.250.16 0.34 0.210.063 0.22 0.16Table 1Grading prole of natural coarse aggregate.

EN sieve size (mm) Percentage passing sieve

Gravel Recycled aggregate

31.5 100.00 100.0020 96.53 100.0016 70.52 98.2212.5 25.45 92.0510 5.97 77.558 2.75 42.936.3 1.77 15.245.6 1.29 3.434 1.06 1.262 0.64 0.401.25 0.52 0.35

Production 40 (2013) 151e160(275 kg m3) for the frost without de-icing salt exposure class.

sitio

C. Medina et al. / Journal of Cleaner Production 40 (2013) 151e160 1532.2.2. Testing methodsThe coarse aggregate resistance to temperature change has been

studied according to different methods: EN 1367-1 y EN 1367-2.The rst tests, the specimens of aggregates in the size range 8e10 mm are exposed to ten freeze-thaw cycles as describe in EN1367-1. The evaluation of the damage is measured by the fractionmaterial smaller than 4 mm. In addition the second tests, thespecimens of aggregates (10e14 mm) are subjected to ve cycles ofimmersion in a saturated solution of magnesium sulphate, followedby oven drying at 110 C. The degradation arising from thedisruptive effects is measured by the extent to which material nerthan 10 mm in particle size.

The consistency in fresh concretes wasmeasured through slumptest, according to European Standard EN 12350-2.

The compressive and splitting tensile strength of concretes was

Fig. 1. Chemical compotested according to EN 12390-3 and EN 12390-6 in concretes beforethe freeze-thaw cycles. These assays were carried out on150 300 mm test cylinders (26 samples/concrete) at 28 days.Also, we have studied the pore structure with mercury intrusionporosimetry (MIP); due to this intrinsic property is a basis for ice orwater content determination under freezing (Zeng et al., 2011).

Table 2Physical, chemical, mechanical and thermal properties of coarse aggregates.

Characteristic Gravel Ceramic

Real density of dry samples (kg/dm3)(EN 1097-6) (ECS, 2001)a

2.63 2.39

Water absorption (wt%) (EN 1097-6)(ECS, 2001)a

0.23 0.55

Flakiness index (wt%) (EN 933-3)(ECS, 2004)a

3 23

Los Angeles coefcient (wt %) (EN 1097-2)(ECS, 2010b)a

33 20

Organic material amount (EN 1744-1)(ECS, 2001c)a

e e

Total porosity (vol. %) (ASTM D 4404-84) 0.23 0.32Loss of mass with freeze-thaw cycles (wt%)

(EN 1367-1) (ECS, 2008b)a0.33 0.05

Magnesium sulphate value (wt%) (EN 1367-2)(ECS, 2010d)a

4 2

a ECS: European Committee for Standardization.The analyser used for the determination of the porosity havebeen a Micromeritics Autopore IV 9500 mercury porosimeter ableto operate at pressures of up to 33 000 psi (227.5 MPa) andmeasurepore diameters of 0.006e175 mm. This trial was conducted to ASTMstandard D 4404 (American Society for Testing and Materials,2004).

Freeze-thaw resistance was assessed by weighing the scaledparticles after 7, 14, 42 and 56 freeze-thaw cycles as described inEuropean standard CEN/TS 12390-9 EX (European Committee forStandardization, 2008a), which is similar to Swedish standard SS13 72 44, also known as the Boras method.

These trials were conducted on four 50 150 150 mm3 slabsper type of concrete. The slabs, in turn, were cut out of the centre ofa 150 150 150-mm3 cube with a diamond saw. The sampleswere then prepared for testing (Fig. 3) as described in the afore-

n of coarse aggregates.mentioned standard (CEN/TS 12390-9 EX) and subsequentlyexposed to 56 freeze-thaw cycles, in which the freezing mediumwas water whose temperature (Fig. 4) was within the intervalspecied in European Standard.

Fig. 2. Recycled ceramic aggregate.

Moreover, the damage caused to the concrete after 56 cycles wasanalysedwithmicrostructural techniques, primarily tomeasure themean and maximum microcrack width in the ITZ between aggre-

3.2. Compressive and splitting tensile strength

Table 3Chemical composition of the cement used (w%).

CaO SiO2 Al2O3 MgO Na2O

CEM I 52.5 R 62.07 19.39 5.22 1.38 0.36

C. Medina et al. / Journal of Cleaner154The compressive and splitting tensile strength values for allconcretes at 28 days rose with the replacement ratio, compressivestrength by 11% and tensile strength by 25% with respect to thereference (RC) in the concrete containing 25% recycled aggregate(CC-25).

This behaviour can be attributed to improvements of theproperties (thickness and modulus of elasticity) of the interfacialtransition zone (ITZ) between ceramic aggregate/paste (Medinaet al., 2012b), with respect the ITZ gravel/paste.

These ndings were consistent with previous reports (Cachim,2009; Pacheco-Torgal and Jalali, 2010) on replacement of naturalaggregate with other types of ceramic waste (brick, tile, etc.).

Table 4Mix proportions.3. Results and discussion

3.1. Consistency and bulk density

Further to the slump test results (6e9 cm), all the concretes hada soft consistency. The graph in Fig. 5 shows that the slump in therecycled ceramic aggregates was smaller than in the control anddeclined with the replacement ratio (Medina et al., 2012). Thisdifference was the result of the linear relationship betweenconsistency and certain physical properties of the aggregates(water absorption, shape and porosity).

The bulk density of the fresh concrete, also shown in Fig. 5,declined with rising replacement ratios, in keeping with the lowerdensity of the recycled ceramic aggregate (see Table 2).gate/paste and in the paste, due to this property is directly relatedto concrete durability (Sahmaran et al., 2012).

This part of the study was conducted on four 30 20 mmcylindrical specimens extracted at random from the four slabs ofeach type of concrete exposed to the freeze-thaw trials. The testsconducted on each specimen are listed in Table 5. The samples wereepoxy coated, precision sawed and their at surfaces carefullypolished for backscattering electron (BSE) microscopic analysis,which was conducted to identify microstructural damage.

The instrumental conditions were: HITACHI model S-4800scanning electron microscope; tungsten source energy-dispersiveX-rays; silicon detector; BRUCKER XFlash Detector 5030 EDXanalyser.Concrete mix Material (kg/m3)

Sand Gravel Ceramic Cement Water

Reference concrete (RC) 716.51 1115.82 0.00 398.52 205.00Concrete containing 20%

recycled aggregate (CC-20)725.81 892.66 216.43 387.64 205.00

Concrete containing 25%recycled aggregate (CC-25)

728.14 836.87 270.53 384.91 205.00control concrete (RC) after 26 and 42 cycles. After 56 cycles,however, the three concretes exhibited the same degree of resis-tance, although scaling was 2.1 and 3.68% lower in CC-20 and CC-25, respectively, than in RC.

This pattern was an indication that RC lost more mass in theearly freeze/thaw cycles, but after 56, the total loss was similar inthe three types of concrete. The difference in the early stages wasdue to the more rened pore structure in the recycled concrete (seeitem 3.3), which had more capillary pores. According to previousreports (Zhou and Mihashi, 2008; Pigeon et al., 1996), a higher3.3. Mercury intrusion porosimetry

The pore size distribution and average pore diameter ndings,graphed in Fig. 6, showed that the volume of macropores declinedwith rising ceramic aggregate replacement ratios, while the volumeof medium-sized capillary pores rose. The combined effect,a decline in the mean pore diameter, was the result of the differ-ences between pore size distribution in the new and the naturalaggregate (see Table 6).

3.4. Freeze-thaw resistance

3.4.1. Coarse aggregate resistance to temperature changeTable 2 gives aggregate resistance to temperature change found

with two methods: freeze-thaw cycles (F) and application ofa magnesium sulphate solution (MS). As these ndings show, whilethe recycled ceramic aggregate exhibited higher resistance than thenatural aggregate, both could be ranked in categories F1 and MS18,pursuant to Tables 18 and 19, respectively, in European standard EN12620. According to that classication, aggregates in these cate-gories are optimal for manufacturing concrete designed to with-stand freezing temperatures.

The difference in concrete thermal performance was attribut-able to the difference in pore size distribution between the recycledand natural aggregates. As Table 6 shows, the new aggregate hadgreater porosity and a larger volume of pores under 4 mm, thefraction that has a benecial effect on concrete freeze-thaw resis-tance (Fernndez, 2007).

Moreover, these ndings are consistent with item F.2.3 ofEuropean Standard EN 12620 and reports by Hazaree et al. (2011),according to which aggregates with a low absorption coefcient(

ed t

aner Production 40 (2013) 151e160 155Fig. 3. Samples expos

C. Medina et al. / Journal of Clerecycled aggregate improves the resistance to abrupt temperaturechange.

Moreover, these results are consistent with earlier observationsreported by Richardson et al. (2011) and Paine and Dhir (2010), whoused C&DW in place of natural aggregate.

Other studies, however, showed a decline in bearing strength inconcrete containing C&DW (Zhu and Li, 2009; Zaharieva et al.,2004) or clay-based roof tile or block waste (Jankovic et al., 2010;Topcu and Canbaz, 2007) as aggregate after exposure to freeze-thaw cycles. This discrepancy in the results can be attributed onthe one hand to the compositional variability in C&DW and on theother to the effect of their quality and some of their physicalproperties (water absorption and fragmentation resistance) ontheir freeze-thaw resistance (Kevern et al., 2010). Such problemscan be solved by adding air-entraining agents (AEA) to the concrete,for the pores formed are able to offset the increase in volumeinherent in freezing (Sahin et al., 2007).

After 56 freeze-thaw cycles, the three types of specimensexhibited much the same appearance, as the photographs in Fig. 8show. The main types of damage included: a) aggregate detach-ment, b) surface deterioration of the coarse aggregate and c) ITZ de-bonding.

Fig. 9 shows that both the inner and outer sides of the recycledceramic aggregate were essentially unaltered at the end of the trial,

Fig. 4. Temperature of the mo freeze-thaw cycles.whereas the surface of the natural aggregate (Fig. 10) showed clearsigns of wear. This nding was directly related to aggregate porestructure, as noted in item 2.1.2.

The energy dispersive X-ray (EDX) ndingswere consistent withthe chemical composition of the materials found with XRD (seeFig. 1).

3.4.3. Microstructure damagesThe microstructural damage caused by freeze-thaw action can

be divided into two main groups: de-bonding at the interfacialtransition zone between coarse aggregate/paste andmicrocracking.

3.4.3.1. De-bonding of the ITZ. Fig. 11 shows that after 56 freeze-thaw cycles, de-bonding was greater at the natural aggregate/paste than at the ITZ ceramic aggregate/paste.

edium freezing (water).

Table 5Number of tests per specimen.

Concrete mix Interface Paste

Gravel/paste Ceramic aggregate/paste

RC 3 e 4CC-20 2 6 4CC-25 2 6 4

ner Production 40 (2013) 151e160C. Medina et al. / Journal of Clea156Differences were observed in interfacial transition zone (ITZ)resistance depending on the part of the ceramic aggregateinvolved: the inner side/paste interface remained practicallyunaltered, whereas resistance along the outer side/paste interfacedeclined slightly under freeze-thaw stress.

These differences were due primarily to the variations inmicro-mechanical properties at the various types of ITZs (EITZinternalpart/paste > EITZexternal part/paste > EITZgravel/paste). This effect was alsoreported by Khan and Siddique (2011), who found that improve-ments in the properties (elastic modulus, microstructure) in thisregion had a benecial impact on freeze-thaw resistance.

Lastly, aggregate/paste interface damage is typical of freeze-thaw action (Gokce et al., 2004) which induces gradual de-bonding and the eventual detachment of the aggregate, as depic-ted in Fig. 11.

Fig. 5. Consistency and de

Fig. 6. Pore size distribution3.4.3.2. Microcracking. In the samples studied, microcracks werefound to appear more frequently in the paste than along theaggregate/paste interface and less frequently yet across the coarseaggregate. Nonetheless, natural gravel was more intensely crackedthan the recycled material.

This distribution of microcracks is consistent with observationsby other authors (Hanjari et al., 2011; Vancura et al., 2011), that

nsity of the concretes.

of concretes at 28 days.

Table 6Total porosity and pore size distribution of aggregates.

Porosity Gravel Ceramic

Total porosity (%) 0.23 0.32Partial porosity (%) 4 mm 0.10 0.15

Fig. 7. Scaled particle mass versus number of freeze-thaw cycles.

Fig. 8. Concrete after 56 freeze-thaw cycles.

Fig. 9. Microanalysis and surface damage in recycled ceramic aggregate (120).

C. Medina et al. / Journal of Cleaner Production 40 (2013) 151e160 157

observed that cracks tend to concentrate in the paste and at theinterface.

Figs. 11 and 12 depict typical interface microcracks. The greaterdetail in Fig.12 also shows how these cracks spread perpendicularlyoutward from the aggregate surface, across the aggregate/pasteinterface and into the paste.

The micrographs in Fig. 13 depict cracking in the concrete paste,which was more intense in the control concrete (RC) than in therecycled concrete containing 25% ceramic aggregate (CC-25). This

effect of tensile strength on freeze-thaw resistance has also beenreported by other researchers (Gencel et al., 2012; Mohamed et al.,2009).

Table 7 gives the mean and maximumwidths of concrete cracksat the aggregate/paste interface and in the paste. The values in thetable reveal a substantial difference in mean and maximummicrocrack widths along the two types of interface. Indeed, the(mean and maximum) values were 92% lower along the interfacebetween the inner side of the ceramic aggregate and the paste than

Fig. 10. Microanalysis and surface damage in gravel (120).

C. Medina et al. / Journal of Cleaner Production 40 (2013) 151e160158was because freeze-thaw-induced cracking is a result of the stressgenerated in the pore system by a number of mechanisms (seeSection 1). When stress is greater than concrete tensile strength,the material cracks. The recycled concretes, which had highertensile strength (see Table 6) consequently cracked less readily. TheFig. 11. Damage at ITZs (1000): a) natural aggregate/paste; b) inner ceramalong the natural gravel/paste interface. These values are consistentwith the results described in item 3.4.3.1.

Themicrocracks in thepaste in the concretes studiedwere slightlynarrower in the recycled materials, with the mean and maximumwidths 6 and 17% smaller, respectively, in CC-25 than in RC.ic aggregate/paste interface; c) outer ceramic aggregate/paste interface.

n at

C. Medina et al. / Journal of CleanerFig. 12. Microcrack distributioLastly, the width of all the cracks was less than the 100 mmdened as the durability limit by some researchers (Sahmaran et al.,2012; Reinhardt and Jooss, 2003) according towhom cracks smallerthan that size, if treated with self-repairing materials, do notcompromise structural feasibility.

Fig. 13. Cracks in c

Table 7Mean and maximum microcrack widths at the aggregate/paste interface in theconcretes studied.

ITZ ecrack (mm) emax(mm)

Concretepaste

ecrack (mm) emax(mm)

Inner side of ceramicaggregate/paste

0.45 0.057 0.52 RC 1.67 0.540 2.27

Outer side of ceramicaggregate/paste

2.58 0.465 3.04 CC-20 1.59 0.283 1.99

Gravel/paste 5.82 0.701 6.59 CC-25 1.57 0.329 1.88Note: ITZ: interfacial transition zone/ecrack: mean widths of concrete cracks/emax:maximum widths of concrete cracks.the aggregate/paste interface.

Production 40 (2013) 151e160 1594. Conclusions

The following conclusions can be drawn from the aforemen-tioned results.

1. Sanitary ware industry aggregate is more resistant to temper-ature change than natural coarse aggregate.

2. The new concrete is more freeze-thaw resistant than conven-tional concrete. The scaling rate is lower and the cracks arenarrower in recycled concrete. Both effects are accentuatedwith rising replacement ratios.

3. According to the results obtained under the present research,these recycled concretes may be apt for use in structuralconcrete when they are in a specic exposure class type withfrost and without deicing salts such as: constructions inmountainous areas and winter resorts. Nevertheless, it isrequiredmore extensive research on durability in further work.

oncrete paste.

ner4. The technical, economic and environmental advantagesattendant upon the potential replacement of natural coarseaggregate with recycled ceramic sanitary ware waste showpromise for construction industry sustainability.

The study of freeze-thaw-induced microstructural damage inconcrete provides highly useful information for predicting themechanical behaviour and permeability of structures throughouttheir service life.

Acknowledgements

The present study was funded by the Spanish Ministry ofScience and Innovation under coordinated research Project(BIA2010-21194-C03-01).

Appendix A. Supplementary data

Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.jclepro.2012.08.042.

References

Abbas, A., Fathifazl, G., Isgor, O.B., Razaqpur, A.G., Fournier, B., Foo, S., 2009. Dura-bility of recycled aggregate concrete designed with equivalent mortar volumemethod. Cement and Concrete Composites 31, 555e563.

ANEFA, 2011. The Aggregates Sector in 2010. National Association Aggregates (inSpanish). www.aridos.org/index.php (accessed 23.07.12.).

ASTM, 2004. D 4404e84: Test Method for Determination of Pore Volume and PoreVolume Distribution of Soil and Rock by Mercury Intrusion Porosimetry. www.astm.org (accessed 23.07.12.).

Blengini, G.A., Garbarino, E., 2010. Resources and waste management in Turin(Italy): the role of recycled aggregates in the sustainable supply mix. Journal ofCleaner Production 18, 1021e1030.

Cachim, P.B., 2009. Mechanical properties of brick aggregate concrete. Constructionand Building Materials 23, 1292e1297.

Commission, E., August 2007. Reference document on best available techniques inthe ceramic manufacturing industry. In: European Commission. eippcb.jrc.es(accessed 23.07.12.).

Debieb, F., Kenai, S., 2008. The use of coarse and ne crushed bricks as aggregate inconcrete. Construction and Building Materials 22, 886e893.

European Committee for Standardization, 2001. EN 1097-6. Tests for Mechanicaland Physical Properties of Aggregates. In: Part 6: DeTermination of ParticleDensity and Water Absorption, p. 34.

European Committee for Standardization, 2004. Tests for Geometrical Properties ofAggregates. EN 933-3. In: Part 3: Determination of Particle Shape. Flakinessindex, p. 14.

European Committee for Standardization, 2008a. Testing Hardened Concrete. CEN/TS 12390-9 EX. In: Part 9: Freeze-thaw Resistance. Scaling, p. 28.

European Committee for Standardization, 2008b. Tests for Thermal and WeatheringProperties of Aggregates. EN 1367-1. In: Part 1: Determination of Resistance toFreezing and Thawing, p. 16.

European Committee for Standardization, 2009. Aggregates for Concrete. EN 12620:2003A1, p. 60.

European Committee for Standardization, 2010a. Tests for Mechanical and PhysicalProperties of Aggregates. EN 1097-2. In: Part 2: Methods for the Determinationof Resistance to Fragmentation, p. 38.

European Committee for Standardization, 2010b. Tests for Thermal and WeatheringProperties of Aggregates. EN 1367-2. In: Part 2: Magnesium Sulphate Test, p. 18.

European Committee for Standardization, 2010c. Tests for Chemical Properties ofAggregates. EN 1744-1. In: Part 1: Chemical Analysis, p. 66.

European Committee for Standardization, 2010d. Eurocode 2: Design ofConcrete Structures. EN 1992-1. In: Parte 1-1: General Rules and Rules forBuilding, p. 244.

Fernndez, M., 2007. Concrete. Engineering Civil Association, Madrid, Spain (inSpanish).

Gencel, O., Ozel, C., Koksal, F., Erdogmus, E., Martinez-Barrera, G., Brostow, W., 2012.Properties of concrete paving blocks made with waste marble. Journal ofCleaner Production 21, 62e70.

Gokce, A., Nagataki, S., Saeki, T., Hisada, M., 2004. Freezing and thawing resis-tance of air-entrained concrete incorporating recycled coarse aggregate: therole of air content in demolished concrete. Cement and Concrete Research34, 799e806.

Hanjari, K.Z., Utgenannt, P., Lundgren, K., 2011. Experimental study of the materialand bond properties of frost-damaged concrete. Cement and Concrete Research41, 244e254.

C. Medina et al. / Journal of Clea160Harrison, T.A., Dewar, J.D., Brown, B.V., 2001. In: Freeze-thaw Resisting Concrete: ItsAchievement in the UK. CIRIA, London, United Kingdom.Hazaree, C., Ceylan, H., Wang, K., 2011. Inuences of mixture composition onproperties and freeze-thaw resistance of RCC. Construction and BuildingMaterials 25, 313e319.

Jankovic, K., Bojovic, D., Nikolic, D., Loncar, L., Romakov, Z., 2010. Frost resistance ofconcrete with crushed brick as aggregate. Architecture and Civil Enginering 8,155e162.

Kevern, J.T., Wang, K., Schaefer, V.R., 2010. Effect of coarse aggregate on the freeze eThaw durability of previous concrete. Journal of Materials in Civil Engineering22, 469e475.

Khan, M.I., Siddique, R., 2011. Utilization of silica fume in concrete: review ofdurability properties. Resources Conservation and Recycling 57, 30e35.

Kosior-Kazberuk, M., Jezierski, W., 2004. Surface scaling resistance of concretemodied with bituminous addition. Journal of Civil Engineering and Manage-ment 10, 25e30.

Liu, L., Ye, G., Schlangen, E., Chen, H., Qian, Z., Sun,W., van Breugel, K., 2011. Modelingof the internal damage of saturated cement paste due to ice crystallizationpressure during freezing. Cement and Concrete Composites 33, 562e571.

Marchand, J., Pigeon, M., Setzer, M., 1997. Freeze-thaw Durability of Concrete:Proceeding of the International Workshop in the Resistance of Concrete toScaling Due to Freezing in The Presence of De-icing Salts, Sainte-Foy, Qubec,Canad: Papers from the International Workshop on Freeze-Thaw and De-icingResistance of Concrete, Lund, Sweden. E & FN Spon, London.

Medina, C., Snchez de Rojas, M.I., Fras, M., 2012. Reuse of sanitary ceramic wastesas coarse aggregate in eco-efcient concretes. Cement and Concrete Composites34, 48e54.

Medina, C., Fras, M., Snchez de Rojas, M.I., 2012b. Microstructure and properties ofrecycled concretes using ceramic sanitary ware industry waste as coarseaggregate. Construction and Building Materials 31, 112e118.

Mohamed, M.A.S., Ghorbel, E. & Wardeh, G. (2009) Effect of freezing e thawingcycles on the physical and mechanical characteristics of concrete. 2nd Inter-national Symposium on Design, Performance and Use of Self-ConsolidatingConcrete (eds C.J. Shi, Z.W. Yu, K.H. Khayat & P.Y. Yan), pp. 460e472.

Pacheco-Torgal, F., Jalali, S., 2010. Reusing ceramic wastes in concrete. Constructionand Building Materials 24, 832e838.

Paine, K.A., Dhir, R.K., 2010. Recycled aggregates in concrete: a performance-relatedapproach. Magazine of Concrete Research 62, 519e530.

Permanent commission of the concrete, 2008. Spanish Code on Structural Concrete.EHE-08.MinisteriodeFomento.CentrodePublicaciones,Madrid, Spain (inEnglish).

Pigeon, M., Talbot, C., Marchand, J., Hornain, H., 1996. Surface microstructure andscaling resistance of concrete. Cement and Concrete Research 26, 1555e1566.

Reinhardt, H.W., Jooss, M., 2003. Permeability and self-healing of cracked concreteas a function of temperature and crack width. Cement and Concrete Research33, 981e985.

Richardson, A., Coventry, K., Bacon, J., 2011. Freeze/thaw durability of concrete withrecycled demolition aggregate compared to virgin aggregate concrete. Journalof Cleaner Production 19, 272e277.

Richardson, A.E., Coventry, K.A., Ward, G., 2012. Freeze/thaw protection of concretewith optimum rubber crumb content. Journal of Cleaner Production 23, 96e103.

Sahin, R., Tasdemir, M.A., Guel, R., Celik, C., 2007. Optimization study and damageevaluation in concrete mixtures exposed to slow freeze-thaw cycles. Journal ofMaterials in Civil Engineering 19, 609e615.

Sahmaran, M., Ozbay, E., Yucel, H.E., Lachemi, M., Li, V.C., 2012. Frost resistance andmicrostructure of engineered cementitious composites: inuence of y ash andmicro poly-vinyl-alcohol ber. Cement & Concrete Composites 34, 156e165.

Salem, R.M., Burdette, E.G., Jackson, N.M., 2003. Resistance to freezing and thawingof recycled aggregate concrete. ACI Materials Journal 100, 216e221.

Snchez de Rojas, M.I., Marin, F.P., Frias, M., Rivera, J., 2007. Properties andperformances of concrete tiles containing waste red clay materials. Journal ofthe American Ceramic Society 90, 3559e3565.

Snchez de Rojas, M.I., Marn, F.P., Fras, M., Valenzuela, E., Rodrguez, O., 2011.Inuence of freezing test methods, composition and microstructure on frostdurability assessment of clay roong tiles. Construction and Building Materials25, 2888e2897.

Shi, X.M., Fay, L., Peterson, M.M., Yang, Z.X., 2010. Freeze-thaw damage andchemical change of a portland cement concrete in the presence of diluteddeicers. Materials and Structures 43, 933e946.

Topcu, I.B., Canbaz,M., 2007.Utilizationof crushed tile as aggregate in concrete. IranianJournal of Science and Technology Transaction B-Engineering 31, 561e565.

Vancura, M., MacDonald, K., Khazanovich, L., 2011. Microscopic analysis of paste andaggregate distresses in pervious concrete in a wet, hard freeze climate. Cementand Concrete Composites 33, 1080e1085.

Vegas, I., Urreta, J., Fras, M., Garca, R., 2009. Freeze-thaw resistance of blendedcements containing calcined paper sludge. Construction and Building Materials23, 2862e2868.

Wardeh, G., Mohamed, M.A.S., Ghorbel, E., 2011. Analysis of concrete internaldeterioration due to frost action. Journal of Building Physics 35, 54e82.

Zaharieva, R., Buyle-Bodin, F., Wirquin, E., 2004. Frost resistance of recycledaggregate concrete. Cement and Concrete Research 34, 1927e1932.

Zeng, Q., Fen-Chong, T., Dangla, P., Li, K., 2011. A study of freezing behavior ofcementitious materials by poromechanical approach. International Journal ofSolids and Structures 48, 3267e3273.

Zhou, Z.Y., Mihashi, H., 2008. Micromechanics model to describe Strain behavior ofconcrete in freezing process. Journal of Materials in Civil Engineering 20, 46e53.

Production 40 (2013) 151e160Zhu, H., Li, X., 2009. Experimental on freezing and thawing durability characteristicsof recycled aggregate concrete. Key Engineering Materials 400-402, 447e452.

Freeze-thaw durability of recycled concrete containing ceramic aggregate1. Introduction2. Materials and methods2.1. Materials2.1.1. Natural aggregates2.1.2. Recycled ceramic aggregate2.1.3. Batching water2.1.4. Cement

2.2. Methods2.2.1. Mixtures composition of concretes2.2.2. Testing methods

3. Results and discussion3.1. Consistency and bulk density3.2. Compressive and splitting tensile strength3.3. Mercury intrusion porosimetry3.4. Freeze-thaw resistance3.4.1. Coarse aggregate resistance to temperature change3.4.2. Scaling surface3.4.3. Microstructure damages3.4.3.1. De-bonding of the ITZ3.4.3.2. Microcracking

4. ConclusionsAcknowledgementsAppendix A. Supplementary dataReferences