Victor Okoro - The study of the effect of polyethylene and polyvinylchloride on the physico-chemical properties of Portland cement.

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      Publication Details (including relevant citation   information):

      I.        INTRODUCTION

    ThetermcementwasderivedfromtheLatinwordCaementummeaninganythingthatbindsorunittwobodiestogether.Itmaybedefinedaspowderedceramicmaterialwhichwhenmixedwithwater,setsand develops adhesiveandcohesiveproperties thatenables tobindupintoacompactmass[1].Portlandcementisa hydrauliccementthatwhencombinedwithwater, hardens intoasolidmass.Interspersedinanaggregatematrix itformsPortlandcementconcrete(PCC)[2].TheuseofcementcanbetracedbacktoEgyptian,Romanand Indianbuilderswhouseddifferenttypesof cementingmaterialslikegypsum,lime,etc,intheir ancient constructions[3].ItwasnotuntilthenineteenthcenturythatJosephAspdindevelopedPortlandcementbyfiring limestonewhichcontainedsomeclayeysoiltoaveryhightemperature.Thisledtotheproductionofcement withsuperiorhydraulicproperties[3]Concrete,whichPortlandcementisamajorpartofit,is madeupof sand orstone,knownasaggregate,combinedwithcementpastetobindit.Thegreaterproportionofconcreteis aggregatewhichisbulkyandrelativelycheaperthanthecement.As muchoftheconstituentsofconcretecome fromstone,itisoftenthoughtthatconcrete hasthesamequalitiesandwilllastforever[4].Inrecentyearsthis concepthasbeenchanged.Manyinvestigationshaveshownthatconcretedoesnotperformaswellasitwas expectedduetotheeffectofmanyfactorswhichcontributetoorcausethedeteriorationofconcretestructures [5].Thesefactorscanbeduetopoormanufactureoraveryaggressiveenvironmentwhichleadstolowflexural strength,lowfailurestrain,susceptibilityto frostdamageandlowresistancetochemicals[6].In certain situations,theseproblemscanbesolvedbyusingmaterialswhichcontainorganicpolymersorresins,insteadof orinconjunctionwithPortlandcement[6].Polymersarelargeclassofmaterialsconsistingofsmallmolecules (monomers)thatcanbelinkedtogethertoformlongchain,thustheyareknownasmacromolecules.They mainlyhavelightweight,aretough,havelowmoduliiandhighstrengthtoweightratio[7].Thesepolymers offertheadvantagesofhighstrength,improveddurability,goodresistancetocorrosionandreducedwater permeability.Therearethreeprincipalclassesofcompositematerialscontainingpolymers.Theseare;polymer impregnatedconcrete(PIC),polymermodifiedconcrete(PMC)andpolymerconcrete(PC)[8].Inthiswork,we reportedtheeffectof polyethyleneandpolyvinylchlorideonthephysico-chemicalpropertiesofPortland cement.

      ii  EXPERIMENTAL

    Materials

      DangotebranoPortlancement  obtainefrom  Ekemarket,  Awka,  Nigeria  wasused  foresearch. The polyethylene plastic bags and polyvinylchloride pipe samples were sourced from waste dumpsroadsides, gutters and streets at Awka , Anambra state, Nigeria. The PE bags were washed with water and detergent, dried and taken to a lumping machine, where they were heated to lumps. The PVC pipe samples weralso washed with water and detergent, dried and cut into smaller sizes. Both the PE lumps and PVC samplewere ground separately using Ferm FMS-200 grinding machine of model: 31010 and speed: 31m/s, to fine powder of 2.55mm mesh size. Portland cement was accurately weighed in a cuboids shaped mould usinelectronic balance of model: LC 120005 and the mass was found to be 756g. The weighed cement was themissed with 200ml of water in a plastic container and introduced into the cuboids shaped mould made of wooand lined with polyethylene sheets. It was allowed to set for 24 hrs. This slab was removed from the mould anwas taken to be 100% cement and served as the control. From 756g of dry cement, 0.1%, 0.5%, 1.0%, 3.0%, 7.0% and 25.0% concentrations of polymers were calculated for each cement-polymer composite and the ratiwas based on pure cement. These various concentrations of the polymers were mixed with the dry cement untithey were evenly distributed in the cement. Water was added in aliquots until a homogenous paste was formed. The mixing was carried out in a plastic container and care was taken to avoid over watering by maintaining aappropriate water/cement ratio. The paste was then poured into the mould. It was kept under a temperature of 250C for 24hrs to setAfter setting, the composites were removed from the mould and cured for 2 weeks. Curing was carried out by immersing the composites fully in water to develop full strength [9]. After curing, thcomposites were taken out to be air dried for 2 days and kept for analysis.

     

      Method  

     

      Thefollowingparametersweredeterminedonthecement-polymercompositesproduced;electricalanthermal  conductivities,  hardness,  abrasion  resistance  and  water  imbibitions.  The  electrical  and  thermaconductivitiesweredeterminedusingASTM,(2009)method[10],thewaterimbibitionwasdeterminedusing theNIS,(2000)method[11]whilethehardnessandabrasionresistancewasdeterminedusingASTM,(1999) method[12].  

       

       

      iii.            RESULTSANDDISCUSSION

       

      Table1:Theresultsofthephysic-chemicalpropertiesofthecement-polymercomposites.

         

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
           

            Filler       

           

            (%)       

         
           

            Polyethylene(PE)       

         
           

            Polyvinylchloride(PVC)       

         
           

            TC       

           

            (kW/m/0C)       

         
           

                      EC (10-6       

           

            Sm-1)       

         
           

            H       

           

            (HRC)       

         
           

            AR       

           

            (mm)       

         
           

            WI       

           

            (%)       

         
           

            TC       

           

            (kW/m/0C)       

         
           

                      EC (10-6       

           

            Sm-1)       

         
           

            H       

           

            (HRC)       

         
           

            AR       

           

            (mm)       

         
           

            WI       

           

            (%)       

         
           

            0.0       

         
           

            0.273       

         
           

            0.55       

         
           

            602       

         
           

            0.138       

         
           

            10.24       

         
           

            0.273       

         
           

            0.55       

         
           

            602       

         
           

            0.138       

         
           

            10.24       

         
           

            0.1       

         
           

            0.167       

         
           

            0.36       

         
           

            462       

         
           

            0.136       

         
           

            6.61       

         
           

            0.315       

         
           

            1.11       

         
           

            477       

         
           

            0.141       

         
           

            1.86       

         
           

            0.5       

         
           

            0.187       

         
           

            0.36       

         
           

            454       

         
           

            0.136       

         
           

            6.15       

         
           

            0.145       

         
           

            0.09       

         
           

            647       

         
           

            0.128       

         
           

            6.56       

         
           

            1.0       

         
           

            0.167       

         
           

            0.33       

         
           

            534       

         
           

            0.135       

         
           

            6.15       

         
           

            0.150       

         
           

            0.44       

         
           

            584       

         
           

            0.132       

         
           

            9.63       

         
           

            3.0       

         
           

            0.172       

         
           

            0.42       

         
           

            633       

         
           

            0.139       

         
           

            14.55       

         
           

            0.205       

         
           

            0.86       

         
           

            694       

         
           

            0.148       

         
           

            7.76       

         
           

            7.0       

         
           

            0.265       

         
           

            0.21       

         
           

            743       

         
           

            0.145       

         
           

            3.44       

         
           

            0.247       

         
           

            0.12       

         
           

            593       

         
           

            0.141       

         
           

            7.61       

         
           

            25.0       

         
           

            0.050       

         
           

            1.50       

         
           

            617       

         
           

            0.739       

         
           

            15.07       

         
           

            0.021       

         
           

            0.02       

         
           

            629       

         
           

            0.162       

         
           

            2.80       

         

      TC = Thermal Conductivity, EC = Electrical Conductivity, H =   Hardness, AR = Abrasion Resistance and WI = Water Imbibition

       

      The results of the physic-chemical properties of the   cement-polymer composites produced are shown in Table 1. The   results of thermal conductivities of the cement-polymer   composites are shown in Fig.1, It is generally observed that the   thermal conductivities of these composites decreased as the   concentration of the polymers increased. The decrease can be   attributed to the positive effect of the polymers in preventing   ions such as Na+, Al3+, Ca2+, etc, in the cement from   transferring heat energy through the openings in the cement   matrix which serves as a medium for heat transfer. This is due to   the good adhesion of the cement matrix to the polymer filler   [13]. It is observed (fig.2) that the electrical conductivities   of the cement-polymer composites decreased as the concentrations   of the polymers increased, though the values for PE composites   were contrary to this observation. The increase in electrical   conductivities for PE- composites at high concentrations is due   to the possession of free polar mobile groups at high   concentrations, the polymer tends to conduct electricity   appreciably at 25% concentration. PVC on the other hand tends to   have low electrical conductivity at high concentration due to the   presence of chlorine attached to the polymer backbone which   prevents free rotation of the polymer chains [14].For hardness   (fig.3), it is observed that the hardness of the composites   increased when the concentrations of the polymers increased to 7%   and thereafter decreased slightly. Hardness is the ability of a   material to resist indentations from applied normal loads.   Although cement materials have excellent hardness, they are   generally brittle and this makes them easily indented when loads   are applied. The polymers used acts as a binder which increases   the mobility/rheology of the cement-polymer composites. The   result is that there is a reduction in both entrapped and   capillary voids. Increased binder content means that the   individual cementgrains are in close proximity to each other   resulting in a denser microstructure in the hardened composites.   It is seen that 7% polymer concentration gives optimal increase   in hardness of the composites before saturation effects sets in.   Abrasion resistance test (fig.4) shows that the abrasion   resistance properties of the cement- polymer composites increased   as the polymer concentration increased until a definite   concentration when the increase in polymer concentration brought   about a decrease in abrasion resistance. Abrasion is the ability   of a slide to wear or scratch a material [15].Materials such as   cement are abraded because of the creation of entrapped voids   which result when cement is molded with water and other   aggregates. These voids result in cement concrete having inferior   abrasion resistance. The polymers act as binders by reducing both   the entrapped air and void in the cement matrix. 7% polymer   concentration gives optimal increase in abrasion resistance of   the composites before saturation effect sets in. It is observed   (fig.5) that the water imbition of the cement-polymer composites   decreased as the concentrations of the polymers increased, except   for PE at 25% concentration which had a high increase in water   imbibitions. Cement when mixed with water, creates entrapped   voids which is a result of trapped air introduced during mixing   operation. This makes the cement material to imbibe water when   used in constructions under water. The polymers in the composites   helps to fill the voids and pores inherent in native cement paste   and so reduce the effective area over which flow can take   place.7% polymer concentration gives effective decrease in the   water imbibitions of the PE composites before saturation effect   sets in.

       

      IV.CONCLUSION

      It is concluded from this investigation that 2.5mm mesh size of   polyethylene and polyvinylchloride

      powder can be used as fillers or rein forcers for Portland   cement. The results of the physico-chemical properties showed   variations in properties of the cement-polymer composites   produced with increasing polymer concentration. The study showed   that the composites will help: in controlling heat conduction in   cement buildings, in reducing electric hazards associated with   cement buildings, in reducing the rate at which under water   cement constructions imbibe water and in the production of cement   materials that will be hard enough to resist indentation and wear   and tear through abrasion at optimal polymer concentrations.

       

      REFRENCES

      [1].http://www.wikipedia.com/portland-cement.html,22/03/2012:14.00.

      [2].           P.C. Hewlett, Chemistry   of cement and concrete (Arnold,CA: Lea ,1998) .

      [3].           A.S. Sambo, A.N. Eboatu   and I.J. Dioha, Cements, ceramics and glass (Bauchi: ATBU   Press,2000)1-13.

      [4].          D.F. Orchard, Concrete   Technology (Essex, England: Applied Science Publishers Ltd, 1973)   311-478.

      [5].L.A. Kuhlmann, Causes, evaluation and repair of cracks in   concrete structures, ACI Materials Journal, July-August,1990,   387- 394.

      [6].J.M. Illston and P.L.J. Domone, Construction Material, Their   Nature and Behavior (New York: McGraw-Hill, Inc., 2001). [7].Y.   Ohama, Concrete Admixtures Handbook: Properties, Science and   Technology (Park Ridge: Noyes Publication, 1984).

      [8].           J. Kosednar and N.P.   Mailvaganam, Selection and use of polymer-based materials in the   repair of concrete structures, Journal of

      [9].           Performance of   Constructed Facilities, 19(3), 2005, 229-233            .

      [10].         S.C. Bhatia (2001), Engineering   Chemistry (New Delhi :CBS. Publishers) 7.

      [11].         ASTM E1225, Guarded Comparative   Measurement Techniques, American Society for Testing of   Materials, E1225-09, 2009.

      [12].         Nigerian Industrial Standard   NIS 439, Standard for Cement ICS 91: 100: 10, 2000.

      [13].Standard Specification for Portland Cement , ASTM C-150,   Annual Book of ASTM Standards, American Society for Testing of   [14].Materials, West Conshohocken, PA, 1999.

      [15].J.A. Larbi and J. Bijen, (1990), Polymers in Concrete, Proc.   of 6th    Int. Conf. on polymers in concrete, Beijing   China, 1990, 185. [16].J.K. Stille, Vinyl addition polymers,   Introduction to Polymer Chemistry (New York: John Wiley and Sons,   1962) 163-171.

      [17].         F.L. Smith,  Effect of   aggregate quality on resistance of concrete to abrasion: Cement   and Concrete, ASTM STP 205, American

      Society for Testing  of Materials, Philadelphia,1958,91-105.

       

      Abstract:

        The goal of this research work is to develop a better way   of handling the problems caused by the failures of cement   concrete structures by forming cement-polymer composites and   identifying the best composite for targeted product.   Polyvinylchloride(PVC) and Polyethylene(PE) were ground into fine   powder of 2.55mm mesh size and were compounded with Portland   cement at various concentrations of 0.0%, 0.1%, 0.5%, 1.0%, 3.0%,   7.0% and 25.0% of pure Portland cement. Physico-chemical   properties of the cement-polymer composites produced were   analysed and the results obtained were compared with pure   Portland cement which served as the control. The results show   that abrasion resistance and hardness of the composites   increased, except at some concentration while water imbibition,   electrical and thermal conductivities of the composites decreased   as the polymer concentrations increased. It is observed that 7.0%   concentration of both polymers gave the best composites when   hardness and abrasion resistance is required. 7.0% PE   concentration gave the best PE composite for electrical   conductivity and water imbibition while 25.0% PVC concentration   gave the best PVC composite for electrical conductivity and water   imbibition.

      Address (URL): www.ijesi.org Volume 2 Issue 8ǁ August 2013 ǁ   PP.23-27