Construction and Building Materials 25 (2011) 1049–1055 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmatUse of waste polymers in concrete for repair of dam hydraulic surfacesJosé Carlos Alves Galvão a,*, Kleber Franke Portella a, Alex Joukoski a, Roberto Mendes a,Elizeu Santos Ferreira ba Centro Politécnico da UFPR, Caixa Postal 19067, CEP 81531-980, Jardim das Américas, Curitiba, Paraná, Brazilb Rua Izidoro Biazetto, 158, CEP 81200-240, Mossunguê, Curitiba, Paraná, Brazila r t i c l e i n f o a b s t r a c tArticle history: The durability of a concrete structure is strongly inﬂuenced by the inadequate use of materials and by theReceived 6 February 2010 physical and chemical effects of the environment of its immersion. The immediate consequence is theReceived in revised form 21 May 2010 anticipated necessity of maintenance and repairs, which must have speciﬁc characteristics, mainlyAccepted 19 June 2010 mechanical and chemical, based on the material of the base or its substratum. In this study differentAvailable online 23 July 2010 repair materials (RM’s) were analyzed and manufactured to be used on concrete hydraulic surfaces of hydroelectric power plant dams that suffered different types of damage, such as erosion–abrasion andKeywords: chemical attacks from the reservoir water. Concrete samples were made from polymeric and elastomerConcreteRepair materials materials proceeding from the recycling industry, such as agglutinated low-density polyethylene (LDPE),Waste polymers crushed polyethylene terephthalate (PET) and rubber from useless tires. The contents of each materialRecycling were 0.5%, 1.0%, 2.5%, 5.0% and 7.5%. Their properties were compared with a reference concrete, without any additions, comparing the compression strength, tensile strength under diametrical compression, underwater erosion–abrasion resistance, microstructure and ﬁeld application. The samples with 2.5% of addition were the most effective, being LDPE the one which presented better performance. Ó 2010 Elsevier Ltd. All rights reserved.1. Introduction crete the possibility to deposit the residual sludge from water treatment stations. The addition of polymeric waste to concrete corresponds to a Different works, as of Rebeiz , Choi et al.  and JO et al.new perspective in research activities, integrating the areas of con- , have analyzed the effect of addition of recycled PET to thecrete technology and environmental technology. properties of concrete. The ﬁbers of recycled PET easily mix in Industrial and domestic waste have a signiﬁcant percentage of the concrete, giving new properties to the material . Khaloopolymeric materials in its constitution, which occupies a consider- et al.  have observed that the addition of tire rubber particlesable volume on landﬁlls. Therefore its recycling is interesting to re- provided the concrete with higher ductility in compressivesearch and development of technologies for minimizing the strength testing, if compared with concrete without addition.problems caused by this waste. One of the advantages of the use of recycled plastic in concrete is Polypropylene (PP) , polyethylene (PE)  and nylon , the reduction of solid waste in landﬁlls .besides other materials [24,17] are examples of polymeric addi- The concrete with addition of polymeric materials, as well astions to concrete, mainly in the ﬁber shape, providing the rein- the FRC, has had a widespread increase in its application, whichforcement of concrete structures, known as ‘‘ﬁber-reinforced can also be seen in Brazil. An appreciable improvement of perfor-concrete” (FRC). mance related to the control of ﬁssures of plastic retraction was Depending on the appropriate ﬁnal target, varied types of waste observed for mortars applied in repair, where the low moduluscan be used in concrete: Portella et al.  and Guerra et al.  of elasticity from ﬁbers was enough to inhibit the propagation ofhave studied the properties of concrete with addition of ceramic cracks. Due to this redistribution of tension, the stored elastic en-waste; Ismail and Al-Hashmi  have studied concrete with recy- ergy was not dissipated through a single source of propagation,cled plastic addition; Angulo et al.  have characterized recycled but, possibly, through several microscopic cracks. The length ofmaterials from construction and demolition as an aggregate for each one of those cracks, as well as the loss of resistance, was smal-concrete; and, amongst others, Hoppen et al.  have found in con- ler than the one caused by a single crack, even for the same consid- ered superﬁcial area . The hydraulic surfaces of concrete barrages are exposed to * Corresponding author. Tel.: +55 41 33616304; fax: +55 41 3361 6137. erosive wearing  and to cracks caused by the pressure of E-mail address: firstname.lastname@example.org (J.C.A. Galvão). crystallized salts in pores  and by the exposition to aggressive0950-0618/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.doi:10.1016/j.conbuildmat.2010.06.073
1050 J.C.A. Galvão et al. / Construction and Building Materials 25 (2011) 1049–1055agents , causing pathologies and requiring frequent mainte- Table 2nance, including the need for periodical repairs. Because of that, Results of chemical analysis of the cement CPII-Z 32.it is necessary to use a RM that presents properties compatible Component Abbreviation % (weight) Standards limits (%)with the ones of the base material, such as the coefﬁcient of ther- Lime CaO 52.68 –mal dilatation, the mechanical resistance, as well as good adher- Silica SiO2 22.54 –ence between both. In the case of concrete hydraulic surfaces, Alumina Al2O3 6.80 –properties as impact resistance, erosion–abrasion and durability Iron oxide Fe2O3 3.22 – Sulﬁte SO3 2.77 64.0are extremely desirable. Horszczaruk  has studied the erosion– Magnesia MgO 6.13 66.5abrasion resistance of different kinds of high resistance concrete Loss on ignition L.O.I. 3.25 66.5in hydraulic structures and observed, among other characteristics, Insoluble residue I.R. 8.88 616that the use of polyvinyl chloride (PVC) ﬁbers has improved theconcrete resistance to underwater erosion–abrasion. Table 3 The present work focused on the search of a feasible solution for Results of the coarse aggregate tests.the recovery of concrete surfaces of hydraulic structures of hydro- Properties Valueselectric power plant dams, its use and, in turn, the reduction ofenvironmental problems caused by the amount of polymeric waste Speciﬁc gravity (dry) 2.88 g/cm3 Speciﬁc gravity (SSS) 2.93 g/cm3in landﬁlls and in the environment in general. Grain size distribution 4.75–12.5 mm Maximum dimension 9.5 mm Module of ﬁneness 5.642. Materials and methods Powder material content 1.3% Organic material content 0.1%2.1. Materials Water absorption 2.0%2.1.1. Cement The cement used was the Portland cement with pozzolan (CPII-Z 32), which wascharacterized by physical–chemical techniques, according to recommendations Table 4from the standards and regulations of ABNT, which is the Brazilian standardization Properties of the ﬁne aggregate.committee. In Tables 1 and 2, the physical and chemical characteristics of the ce-ment are presented, respectively. Properties Values Speciﬁc gravity 2.61 g/cm3 Module of ﬁneness 18.104.22.168. Coarse aggregate Powder material content 0.3% Crushed basaltic rocks were used as coarse aggregate, with a maximum dimen- Organic material content 0.2%sion of 9.5 mm. In Table 3, the properties of the aggregate are presented. Water absorption 0.2%2.1.3. Fine aggregate Natural washed sand was used in the making of the concrete. The properties of Table 5the ﬁne aggregate are listed in Table 4. Properties of the recycled materials. Property Material2.1.4. Polymeric waste Two polymers from the plastic recycling industry were used: LDPE and PET. The LDPE PET TIREagglutinated LDPE was resultant from the processing of plastic packs (bags of gar- Density (kg/m3) 860 1320 660bage and plastic bags). In the recycling industry this material was selected, sepa- Absorption (%) 7.4 3.9 2.1rated, washed, crushed and agglutinated by mechanical process at anapproximate temperature of 60 °C. The PET came from liquid deodorant ﬂasks. Afterthe selective collection, the material went through the process of separation, having Table 6been previously washed and crushed. Sieve analysis of the polymeric waste and sand. In complement to this work, vulcanized natural rubber ﬁbers (elastomer) werealso applied, gathered from the treads of useless tires from the recycling industry. Sieve Cumulative retained (%) The polymeric waste was characterized in agreement to Mercosul standards,NBR NM numbers 30/01, 52/02 and 53/02. The properties of the polymeric waste Number Size (mm) PET LDPE TIRE Sandare presented in Table 5. The sieve analysis of the polymeric waste and sand are 1/2 inch 12.5 4 0 0 0presented in Table 6. 3/8 inch 9.5 19 0 0 0 1/4 inch 6.3 46 0 0 0 4 4.8 62 2 0 02.2. Mixture proportion 8 2.4 92 24 1 3 16 1.2 96 73 14 13 To optimize the mixture of each one of the constituent materials of the con- 30 0.6 100 93 41 36crete, mixing studies were made, verifying the workability and, later, the axial com- 50 0.3 100 99 84 72pressive strength. The idealized composition, considering a slump stipulated at 100 0.15 100 100 98 98(30 ± 10) mm, was of 1:1. 93:3. 07:0. 45 (c:s:g:w/c), with a cement consumptionof 389 kg/m3. This mixture was considered the reference concrete (RC), with theelastomer and the polymeric waste being added in different contents. Contents of 0.5%, 1.0%, 2.5%, 5.0% and 7.5% of TIRE, PET and LDPE, in weight, In order to keep the water/cement ratio (w/c) and the slump stable, a plasticiz- were added to the RC mixture, in partial replacement of the ﬁne aggregate. In Ta-ing additive was used, based on the works of Siddique et al. . ble 7, the resultant compositions are presented. The polymeric wastes have lower speciﬁc gravity than the sand (Tables 5 and 6). This resulted in a greater volume of recycled material in admixture of concrete Table 1 causing less workability and requiring addition of plasticizer in order to keep the Results of physical tests in cement CPII-Z 32. stipulated slump, but the water–cement ratio was always invariable at 0.45 (Table 7). Properties Values Fineness 3440 cm2/g 2.3. Compressive strength and tensile strength under diametrical compression tests Initial setting time 5 h:10 min Final setting time 6 h:10 min The compressive strength test and tensile strength under diametrical compres- Density 2.97 g/cm3 sion test were carried in agreement to the standards NBR 5739/07 and NBR 7222/ 94, respectively. The three polymeric waste products, TIRE, PET and LDPE, were
J.C.A. Galvão et al. / Construction and Building Materials 25 (2011) 1049–1055 1051Table 7Mixtures of concrete with addition of polymeric waste. Material Cement Coarse Sand Polymeric Polymeric Admixture (kg/m3) aggregate (kg/m3) waste waste (%) plasticizer (kg/m3) (kg/m3) (% cement) RC 389 1193 750.00 – – – TIRE0.5 389 1193 746.25 3.75 0.50 – TIRE1 389 1193 742.50 7.50 1.00 0.20 TIRE2.5 389 1193 731.25 18.75 2.50 0.20 TIRE5 389 1193 712.50 37.50 5.00 0.30 TIRE7.5 389 1193 693.75 56.25 7.50 0.40 PET0.5 389 1193 746.25 3.75 0.50 – PET1 389 1193 742.50 7.50 1.00 – PET2.5 389 1193 731.25 18.75 2.50 – PET5 389 1193 712.50 37.50 5.00 0.20 PET7.5 389 1193 693.75 56.25 7.50 0.30 LDPE0.5 389 1193 746.25 3.75 0.50 0.20 LDPE1 389 1193 742.50 7.50 1.00 0.20 LDPE2.5 389 1193 731.25 18.75 2.50 0.20 LDPE5 389 1193 712.50 37.50 5.00 0.40 LDPE7.5 389 1193 693.75 56.25 7.50 0.50tested in all studied contents: 0.5%, 1.0%, 2.5%, 5.0% and 7.5% (percentage in weight)in substitution of the ﬁne aggregate. Those concrete samples were compared withthe RC. The evolution of the resistance was followed by testing at the ages of 7, 14and 28 days, with two specimens for each age. In tensile strength under diametrical compression testing, two specimens wereanalyzed, at the age of 28 days, for each studied mixture.2.4. Underwater erosion–abrasion resistance For the analysis of erosion–abrasion resistance using the underwater method,ASTM C 1138/97 standard was followed. Cylindrical concrete samples with diame-ter of 300 mm and height of 100 mm were cast. After 28 days of curing in a humidchamber, with a relative humidity higher than 95% and controlled temperature of(23 ± 2) °C, the underwater erosion–abrasion resistance of the concrete was evalu-ated in contents of 2.5% and 5.0% (percentage in weight), for the three studied mate- Fig. 1. (a) View of the spillway; (b) detail of the displacement of the covering andrials. The RC was also evaluated. carbonation layers.2.5. Accelerated aging in SO2 chamber and SEM microstructure investigation Preliminary studies of the adhesion resistance of the RM’s to the samples ex- tracted from the dam have indicated the need of applying a tack bridge on the To test the durability of the developed mixture, prismatic reinforced concrete dry substratum surface. For that, a high viscosity Epoxy resin was used as structuralsamples were manufactured, within the dimensions of (71 Â 100 Â 25) mm. adhesive to the resin base. The necessity of this type of tack bridge was evidenced Those samples were aged for 180 days in a humid climatic chamber, having SO2 by studies carried out at laboratory.at 0.67% (in volume) and internal temperature of (40 ± 3) °C (ASTM 87/07-Method A The RM was put on the substratum with a trowel, being compacted with pylon,– Continuous Exposition) . in order to improve the contact and remove the conﬁned air bubbles. After this period, these samples were manually broken and its surfaces analyzed The ﬁnal superﬁcial ﬁnishing was made with a metallic plate, which gave to theby Scanning Electron Microscopy (SEM), in Philips equipment, model XL30, ﬁnished surface a smoothened aspect.equipped with Energy Dispersive Spectroscopy (EDS). Applications of RM in a total of seven distinct points were made, analyzing the RC, as well as the recycled and elastomer materials, according to the mixtures stud- ied in laboratory (Table 6). Those repair areas had their performance analyzed2.6. Field application throughout the time, in terms of its compatibility with the substratum and of the existence of edge effect and other defects. For the ﬁeld application, the dosages with 2.5% and 5% of addition in weightwere selected, from TIRE, LDPE and PET, as well as the RC, to be applied in the spill-way surface of Mourão Hydroelectric Power Plant dam, located in the city of CampoMourão, in the State of Paraná, Southern Brazil. 3. Results and discussion The points of application of the RM’s were selected in the spillway after a com-plete observation of the state of its conservation and of the localization of defectsdisplayed in the concrete blocks, as illustrated in Fig. 1. 3.1. Compressive strength Initially, points that presented superﬁcial defect and/or signals of previous re-pairs were identiﬁed, with its areas being delimited. The dimension was of The curves of the resistances of the axial compression of the(750 Â 750) mm, which became the standard area determined for the application RMs studied (LDPE, PET and TIRE) and the CR, in terms of the cur-of RM’s. In the points where the extension of the pathology exceeded 750 mm, rect-angular repairs were done, maintaining the repaired areas constant. Thus, a com- ing age, are presented in the graphs of Figs. 2–4, respectively. Forparative standard of performance for each type of employed material was obtained. the three different studied materials and its respective contents The places were cut in the lines that limited the selected areas, thus determin- it was evidenced that the results obtained in the assays of com-ing the area of the repairs. A process of humid cut was done with the use of a saw pressive strength in terms of curing were inversely proportionalcontaining a special diamond disc. to the contents of recycled ﬁber addition. This trend was also no- After the cutting process, the scariﬁcation process was made with an electrome-chanical hammer. In this procedure three pieces of equipment with different ticed by Choi et al.  when they studied the effects of the additionstrength and gauge were used. The heavier pieces of equipment were used for of residues from PET bottles to the properties of concrete, and bythe initial work and removal of degraded material until ﬁnding a surface without Ismail and Al-Hashmi , in the adhesion resistance betweendefects or voids in the concrete. the surface of polymeric waste and the cement paste. Li et al. The mixtures of concrete in ﬁeld followed the same procedure used in the lab-oratory for concrete with polymeric waste.  have also veriﬁed a reduction in the compressive strength of The cleaning of the points of application of the RM’s was executed with water the concrete with tire ﬁbers, not relating such loss to any charac-spurts, removing all the dust and small fragments of removed material. teristic of the material.
1052 J.C.A. Galvão et al. / Construction and Building Materials 25 (2011) 1049–1055 40 40 Compressive strength (MPa) Compressive strength (MPa) 30 30 20 20 RC RC LDPE 0.5% TIRE 0.5% 10 LDPE 1.0% 10 TIRE 1.0% LDPE 2.5% TIRE 2.5% LDPE 5.0% TIRE 5.0% LDPE 7.5% TIRE 7.5% 0 0 0 5 10 15 20 25 30 0 5 10 15 20 25 30 Curing ages (days) Curing ages (days)Fig. 2. Compressive strength in terms of curing time for concrete made with Fig. 4. Compressive strength in terms of curing time for concrete made withrecycled LDPE. recycled tire. 40 an increase in compressive strength compared to the RC. This in- crease in compressive strength was observed in PET with content Compressive strength (MPa) of 2.5% of addition of recycled material. For the highest contents of addition of polymeric waste a decrease in the compressive 30 strength of concrete occurred. For the three materials, the ideal content in the mixture was established as of 2.5%, in weight, the PET2.5 having the best perfor- 20 mance, with (36.0 ± 0.6) MPa, followed by the other two materials, LDPE2.5 and TIRE2.5, with very similar values between both, of (33.9 ± 0.4) MPa and (33.7 ± 0.4) MPa, respectively, at 28 days, as RC PET 0.5% illustrated in Fig. 5. 10 PET 1.0% Although the reduction noticed in the compressive strength of PET 2.5% these mixtures of concrete, the values are of moderate to high PET 5.0% PET 7.5% resistance . Such compositions can be used in poles and 0 cross-arms of reinforced concrete for electrical energy distribution 0 5 10 15 20 25 30 lines, therefore, can also be used in the proper area of energy. As Curing ages (days) the inferior boundary value of this property recommended for such structures is of 25 MPa (NBR 8451/98), only the trace TIRE7.5 mustFig. 3. Compressive strength in terms of curing time for concrete made with be excluded.recycled PET. Additionally, the tests indicated: compressive strength approx-imately equal or superior to the presented, at 7, 14 and 28 days of 40 LDPEcuring, by RC (34.3 ± 0.5) MPa, in compositions LDPE0.5, LDPE1 and PETLDPE2.5; PET0.5, PET1, PET2.5 and PET5; and TIRE0.5 and TIRE2.5. 35 TIRE RC Compressive strength (MPa)Evaluating the traces with TIRE, the need of improvement of dos-age process and conformation was noticed, as long as the interme- 30diate composition TIRE1 presented, at 28 days, lower compressivestrength, being also below the corresponding value of RC. 25 Bayasi and Zeng  showed similar effect on compressive 20strength with the addition of polypropylene ﬁbers, where thecontrol mixture (without polymeric ﬁbers) showed a lower 15compressive strength compared with mixtures with the additionof polypropylene ﬁbers in given content. The 12.7 mm-long poly- 10propylene ﬁbers improved the compressive strength of concretewhen used at volume fraction of 0.3%; in this case the increase 5was 19.3% when compared with the control mixture. When usedat content of 0.5%, a decrease of 2.5% of compressive strength 0 0 0,5 1,0 2,5 5,0 7,5was noticed in concrete, in comparison with control mixture. Content (%) Experimental results showed that addition of polymer materialsat lower contents caused no adverse effects on the compressive Fig. 5. Comparative graph of compressive strength, at 28 days, of concretes withstrength of concrete (Fig. 5). The LDPE0.5 and TIRE0.5 presented additions of waste and its respective contents.
J.C.A. Galvão et al. / Construction and Building Materials 25 (2011) 1049–1055 1053 The environmental advantage of the use of rubber in concrete 3.3. Erosion–abrasion resistancemixtures can be evidenced in the experiment made with TIRE2.5mixture in test poles to be used at electrical energy distribution In Table 8, the values of mass loss, after 72 h of erosion–abra-net in the Northeast region of Brazil . Four structures were con- sion (underwater method), of CR and of concretes made with poly-formed, immobilizing about 20 kg of material, or 5 kg/pole. Consid- meric waste in contents of 2.5% and 5.0% are presented.ering that about 4 kg of fragmented rubber can be removed from a Regarding mass loss by underwater erosion–abrasion, it wasuseless tire, or about 0.8 kg from its tread and sidewall, in this case observed that CR presented the best results, in comparison withabout one entire tire can be disposed for each pole. In the case the concrete made with addition of 2.5% of polymeric waste. How-where only the rubber from the tread is used, the number ups to ever, for the content of 5%, the concrete made with addition of PETsix tires. In the same Northeast region of Brazil, the local company and LDPE presented better results than the concrete without anyof electrical energy has an asset of 6 million units of installed poles, addition. Horszczaruk  veriﬁed that the concrete strengthenedbeing foreseen annual substitutions of, approximately, 60,000 with polymeric ﬁber has higher abrasive resistance when com-units, or, an equivalent immobilization of 300 tons of rubber per pared with concrete without ﬁber addition.year or about 75,000 units of this type of tire. Following the recom- The resistance to erosion–abrasion, after 72 h, decreased in themendations of concrete pole standards (NBR 8451/98), the forecast following order: LDPE, PET and TIRE. Such results can be attributedof such immobilization is of 35 years maximum. to shape, texture and elastic module of the employed materials: the LDPE, with average grain diameter smaller than 0.4 mm, had the best performance, with mass loss of around 7.46% for LDPE2.53.2. Tensile strength under diametrical compression composition. The poorest performance was presented by the mate- rials with the compositions TIRE2.5 and TIRE5. This can be based When the RM’s were compared in terms of tensile strength un-der diametrical compression, results indicated an unexpectedbehavior, without any direct relationship between strength, con-tent or type of the waste added to the concrete. Based on Siddique Table 8 Mass loss of concrete samples under erosion–abrasionet al.  this behavior happens due to the absence of a fragile fail- (underwater method).ure, typical of conventional concrete. In the graph of Fig. 6, results of splitting tensile strength of con- Material Mass loss (%)cretes are presented. CR 6.57 No direct relationship was veriﬁed between tensile strength un- TIRE2.5 8.41 TIRE5 7.39der diametrical compression and recycled material content. On PET2.5 8.07average, the best results were for contents of 1% and 2.5%, in PET5 5.04weight, for the three materials, with prominence of LDPE2.5, which LDPE2.5 7.46presented tensile strength under diametrical compression of LDPE5 3.943.95 MPa, at 28 days. One of the important factors to be investigated regarding theanalysis of ﬁber-reinforced concrete is the relationship betweencompressive strength and tensile strength. For conventional con- (a) 4crete, tensile strength under diametrical compression is about10% of the compressive strength. For LDPE, PET and TIRE materials, in the analyzed contents, therelationship between compressive strength and tensile strengthunder diametrical compression was of (10.4 ± 0.8)%. In this situa- 1 2tion, the ﬁbers of the added materials worked as reinforcement,preventing the propagation of cracks [18,10,23]. 5 3 LDPE PET TIRE 4 RC Tensile strength (MPa) (b) 3 2 1 0 0 0,5 1,0 2,5 5,0 7,5 Content (%)Fig. 6. Comparative graph of splitting tensile strength of concretes with addition of Fig. 7. Micrograph by SEM of TIRE5 concrete (a) and respective EDS specter of thewaste and its respective contents. analyzed region (b).
1054 J.C.A. Galvão et al. / Construction and Building Materials 25 (2011) 1049–1055on its higher water absorption ratio, which is explained by the resultant image or replica of the place that contained one of thehigher amount of communicating pores and, consequently, smaller blades of PET (b). In this last case, the lack of adherence betweenaverage compressive strength, with the rupture process happening, the paste and the material was probably caused by the increasedin most of the cases, in the interface ‘‘cement paste|ﬁber”, corrob- smoothness of the polymer texture. In the same image, otherorating with the works of Raghavan and Huynh . places of removing of the related blades can be seen. Although the tests of aging by SO2 were equally made with all the specimen, the results indicated that these two compositions had superior per-3.4. Microstructure after aging by SO2 formance, not having in their broken surfaces and pores crystals of chemical phases containing sulfur, resultant from the chamber of In Fig. 7, the micrograph obtained by SEM of the broken surface tests or from the proper composition of cement.of one of the TIRE5 specimens is presented, after the aging processof the specimen during 180 days in a humid chamber containing 3.5. Application in ﬁeldsulfur dioxide. Its respective specter of semi quantitative elemen-tary chemical composition is also shown. The concretes with addition of polymeric waste and the CR did In the inspected region it is shown the interface between the not present any technical problems at the moment of its applica-rubber and the paste, the proper rubber (1) and, all over the exten- tion as RM on the spillway surface of Mourão powerplant dam.sion of the region and in diverse parts of the sample, crystals of As quoted by Siddique et al., the addition of polymeric waste re-portlandite (2), gypsum (3), and ettringite (4), indicating a progres- duced the workability of the concrete. This reduction has been cor-sive degradation process of the structure . This composition, in rected with the use of plasticizing additive, keeping slump ﬁxed atrelationship to PET and LDPE, presented a greater tendency to for- (30 ± 10) mm for all materials applied in ﬁeld.mation of these crystals, which are capable of compromising the The tack bridge, with the use of structural adhesive based on andurability of concrete at industrial environments, given the ten- epoxy resin of high viscosity, proved to be, in the ﬁrst hours, a reli-dency to higher concentrations of SOx gases in those areas. The able element in the increase of tack resistance between the oldspecter of the region, obtained by EDS, is also shown in Fig. 7, being concrete (substratum) and the new fresh concretes (RM).possible to point out the presence of the chemical element sulfur, In Fig. 9a, one of the six compositions applied in the spillway ofthat can be part of the proper elastomer and phases of sulpho-alu- Mourão powerplant is shown the repair material based on TIRE2.5,minates, ettringite and gypsum which are present. with 270 days of age and, in Fig. 9b, the details of its interface with In Fig. 8, the micrographs by SEM of the broken surfaces of the the substratum. Until the present moment, defects proceedingcompositions LDPE5 (a) and PET5 (b) are presented, respectively. It from the application, edge or deleterious actions (erosion–abra-is evident the presence of polymeric waste from the partially in- sion) caused by the environment or the water ﬂow in the ﬂowingserted materials in the paste, speciﬁc from LDPE (a), and also the periods of the barrage’s reservoir have not occurred.Fig. 8. Images by SEM of concrete with addition of polymeric waste: (a) LDPE5; (b) Fig. 9. Photos of the RM based on TIRE2.5. (a) Detail of the region containing the RMPET5. TIRE2.5; (b) detail of its interface with the substratum.
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(5) The concrete samples studied did not present technical  LI G, Garrick G, Eggers J, Abadie C, Stubbleﬁeld MA, Pang S. Waste tire ﬁber modiﬁed concrete. Compos Part B: Eng 2004;35:305–12. problems during their application as repair materials in the  Mesbah HA, Buyle-Bodin F. Efﬁciency of polypropylene and metallic ﬁbres on hydraulic surface of the dam. For those materials, until the control of shrinkage and cracking of recycled aggregate mortars. Construct present moment, edge effect has not been identiﬁed. Build Mater 2008;13:439–47. (6) The addition of polymeric waste is viable, mainly when  Neville AM. Properties of concrete. 4th ed. New York, USA: John Wiley & Sons, Inc.; 1996. there are expected improvements in the properties of  Ochi T, Okubo S, Fukui K. Development of recycled PET ﬁber and its application dynamic order as resistance to the erosion–abrasion and of as concrete-reinforcing ﬁber. Cem Concr Compos 2007;29:448–55. optimization or reduction of solid rejects in landﬁlls. It was  Ogi K, Shinodab T, Mizuic M. Strength in concrete reinforced with recycled CFRP pieces. Compos Part A: Appl Sci Manuf 2005;36:893–902. veriﬁed that tons of rejects can be used in the energy distri-  Peret CM, Salomão R, Zambon AM, Pandolfelli VC. Reforço mecânico por ﬁbras bution industry, in manufacturing of civil structures (poles poliméricas e seus efeitos na secagem de concretos refratários. Cerâmica and cross-arms) cast with similar composition. 2003;49:257–61.  Portella KF, Joukoski A, Franck R, Derksen R. Reciclagem secundária de rejeitos de porcelanas elétricas em estruturas de concreto: determinação do The use of recycled materials added to concrete is a technology desempenho sob envelhecimento acelerado. Cerâmica 2006;52:155–67.that can constantly be improved, regarding technical and environ-  Portella KF, Joukoski A, Cabussu MS, Inone PC, Pedreira DP, Piazza F, et al. Mapeamento ambiental para a determinação do grau de corrosividade e demental conditions. Therefore, studies in this area are promising to degradação de materiais das redes aéreas de distribuição de energia elétricaits dissemination in the market. com soluções corretivas. PROJETO DE PESQUISA COELBA, LACTEC e ANEEL, 20, 2008 [in Portuguese].  Raghavan D, Huynh H. Durability of simulated shredded rubber tire in highlyAcknowledgements alkaline environments. J Mater Sci 1997;33 [Nova Iorque].  Rebeiz KS. Time-temperature properties of polymer concrete using recycled PET. Cem Concr Compos 2007;17:603–8. To UTFPR and CAPES for the concession of PIQDTEC; to CNPq –  Siddique R, Khatib J, Kaur I. Use of recycled plastic in concrete: a review. WastePIBITI, for the allowance of technological initiation (Process Manage 2008;28:1835–52.303729/2008-2), to UFPR – PIPE; to COPEL, to LACTEC and ANEEL,  Sivakumar A, Santhanam M. Mechanical properties of high strength concrete reinforced with metallic and non-metallic ﬁbres. Cem Concr Composfor the ﬁnancing and the infrastructure for the conduction of this 1995;29:119–24.research project; to MENNOPAR for the supply of polymeric waste.  Song PS, Hwang S, Sheu BC. Strength properties of nylon- and polypropylene- ﬁber-reinforced concretes. Cem Concr Res 2005;35:1546–50.  Tambelli CE, Schneider JF, Hasparyk NP, Monteiro PJM. Study of the structureReferences of alkali–silica reaction gel by high-resolution NMR spectroscopy. J Non-Cryst Solids 2006;352:3429–36. American Concrete Institute. Concrete Repair Manual, Document no: ACI  Zoorob SE, Suparma LB. Laboratory design and investigation of the properties 210.1R-94. Compendium of case histories on repair of erosion-damaged of continuously graded Asphaltic concrete containing recycled plastics concrete in hydraulic structures, 1999. aggregate replacement (Plastiphalt). Cem Concr Compos 2000;22:233–42.