波特蘭石灰石水泥和混凝土的性能分析材料科學(xué)與工程畢業(yè)論文外文資料翻譯

1、題 目波特蘭石灰石水泥和混凝土的性能分析學(xué)院材料科學(xué)與工程專業(yè)材料科學(xué)與工程班級XXXXXX學(xué)生xx學(xué)號xxXXXXXX指導(dǎo)教師XXXX二零一三年四月二十日Cement & Concrete Composites 24 (2002) 371378An analysis of the properties of Portland limestonecements and concreteS. Tsivilisa,*,E. Chaniotakis b,G. Kakali a,G. Batis aa Chemical Engineering Department, National Tech

2、nical University of Athens, 9 Heroon Polytechniou St., 15773 Athens, Greeceb Department of Research and Development, Titan Cement Company S.A., Kamari Plant Viotias, P.O. Box 18, 19200 Elefsis, GreeceAbstractIn this paper the main factors afecting the properties of Portland limestone cements are dis

3、cussed while the hydration behavior of limestone cements is examined. In addition, the intergrindingprocess, concerning the production of the limestone cements, is studied. Finally the properties and the behavior of limestone cement concrete as well as the corrosion behavior of limestone cement mort

4、ar are investigated. It is concluded that the fineness of clinker and limestone is strongly connected with the limestone content andthe fineness of the cement. The limestone cementsindicate satisfactory strength and generally demand less water than the relative pure cements.The limestone addition im

5、proves the clinker reactivity and the exploitation of its hydraulicpotential. The Portland limestone cements indicate competitive concrete properties and improve the corrosion performance of the concrete. 2002 Elsevier Science Ltd. All rights reserved. Keywords: Portland limestone cement; Intergrind

6、ing; Cement properties; Hydration; Concrete properties; Corrosion1. Introduction The use of Portland limestone cements seems to have many benefits, both technical and econmic al 1-3. In addition, the European Standard EN 197-1 identifies two types of Portland limestone cement containing 6- 20% limes

7、tone (type II/A-L) and 21-35% limestone (type II/B-L), respectively 4. It is expected that the future world production of Portland limestone cement will be continuously increased. The wide use of limestone cement requires a thorough knowledge of the cement and concrete properties. As far as the ceme

8、nt is concerned, the research work is focused on three areas. The first one is the efect of limestone on the cement performance 3,5-8. The second one deals with the participation of limestone in the hydration reactions of clinker 9-19, while the third one with the production process and specifically

9、 the intergrinding of clinker and limestone 5,20-22. Although there is a disagreement in many partial topics, the knowledge level is satisfactory and continuously extended.As far as the limestone cement concrete is concerned, the few available references are focused on two areas. The first one is th

10、e efect of limestone on the concrete properties and behavior 23-29. The second one deals with the ''thaumasite problem'', correlated with the use of limestone cement concrete and calcareous aggregates. RecentresearchworkshowsthatPortlandlimestone cement pastes are susceptible to the

11、thaumasite forma- tion, due to sulfate attack at 5, after only a few months exposure to sulfate solutions 30-35. In this paper the main factors afecting the properties of Portland limestone cements are evaluated, while the hydration behavior of the limestone cements is examined. In addition, the int

12、ergrinding process, concerning the production of the limestone cements, is studied. Finally the properties and the behavior of limestone cement concrete as well as the corrosion behavior of limestone cement mortar are investigated. This work is a part of a project, developed in our laboratories, con

13、cerning the properties of limestone cement and concrete. 2. Intergrinding of clinker and limestone OrdinaryPortlandclinkerofindustrialoriginand limestone of high calcite content (CaCO 3: 95.3%) were used (Tables 1 and 2). Four clinker/limestone mixtures, containing 10%, 20%, 30% and 40% limestone, r

14、espectively, were ground to four diferent fineness each one in a pro-pilot plant ball mill (16 samples CLi-j of Table 3). Table 1Chemical and mineralogical composition of clinkerTable 2Chemical composition (%) of limestoneTable 3Particle size distribution (passing %) of clinker, limestone and mixtur

15、eaCLi-j: C: clinker, L: limestone, i: limestone content (%), j: grinding time (A¼35 min, B¼50 min, C¼65 min,D¼85 min).bCEM: mixture (cement).cS: specic surface (Blaine), n: uniformity factor of RR distribution.In order to determine the particle size distribution of clinker and li

16、mestone after their intergrinding, a sedimentation method (Andreasen apparatus) was used. A sample of each mixture was well dispersed in absolute ethyl alcohol. At predefined time intervals samples were withdrawnusingapipet.Theselectedtimeintervals correspond to particle sizes less than 32, 16, 8 an

17、d 4 lm. The alcohol was removed by drying and the limestone content was determined by measuring the loss of ignition (LOI) at 1000. Finally, the particle size distribution of clinker and limestone was computed. The Rosin-Rammler distribution was used for de-scribing the particle size distribution of

18、 the interground samples. The values of the uniformity factor ðnÞ have been computed (Table 3). It is seen that the increase of the limestone content, as well as the increase of the ce-ment fineness, leads to wider particle size distribution. The particle size distribution of the clinker i

19、s significantly diferent than that of the mixture. The limestone is concentrated in the fine fractions (<8 lm), while the clinker is concentrated in the coarser fractions. Fig. 1 presents limestone and clinker contents of the diferent size fractions. It is seen that the limestone content in the f

20、raction with size less than 4 lm is 24.8% and the clinker contentis75.2%.Itmustbenoticedthattheinitial sample contains 20% limestone and 80% clinker. However, the size fraction greater than 56 lm contains only 12% limestone. According to data given in Table 3, the increase of the mixture fineness in

21、uences the clinker fineness but not to a significant degree. In addition, a limestone content over 30% obstructs the grinding of both clinker and reduced clinker and limestone finenesses, compared with those containing 30%. All the above results show that the particle size distribution of the Portla

22、nd limestone cements, as well as the finenesses of clinker and limestone, is strongly con- nected with the limestone content and the fineness of the mixture. In order to produce a Portland limestone cement of desired properties, the grinding to higher fine- ness (compared with the pure cements) is t

23、he easy way, but the proper one is to define the optimum fineness level, taking into account the limestone content and the grinding properties of the components.3. Properties of Portland limestone cementsPortland limestone cements were produced by inter- grinding of clinker (Table 1), limestone (Tab

24、le 2) and gypsum in a pro-pilot plant ball mill of 5 kg capacity. The composition and the properties of the cements tes- ted are given in Table 4. Fig. 2 shows the inuence of limestone content on the strength development of CL-c-45. It is observed that the addition of 10% limestone does not signific

25、antly alter the compressive strength at any age of samples having fineness up to 3800 cm 2=g. Further increase of the cement fineness leads to the production of limestone cements having compressive strength lower than the pure ones. In general, the inuence of the fineness on the compressive strength

26、 is stronger for limestone addition up to 10%. Table 4 also presents the cement paste water demand, the setting time and the expansion of the tested samples. Thelimestonecements,despitetheirhigherfineness, generally demand less water than the relative pure cements. In limestone cements containing 10

27、% limestone, there is a reduction of water demand from 26% to 25%. Theincreaseofthelimestonecontentto20%and 35% causes a decrease of the water demand to 23.5- 22.8%. The efect of limestone on the paste water demand of cements can be attributed to the diferent particle size distributions of the sampl

28、es. Limestone cements despite their higher fineness have wider particle size distributions - lower value of uniformity factor (n) of the Rosin- Rammler distribution-compared with Portland cements (Table 4). This is due to the intergrinding of an easy-ground material such as limestone with the clinke

29、r.The initial and final setting times of limestone cements (Table 4) are similar to those of the Portland cements. The soundness of the limestone cements (Table 4) is satisfactory. The expansion measured according to the Le Chatelier process varies from 0.5 to 1.5 mm while the limit according to EN

30、197-1 is 10 mm.Fig. 1. Limestone (L) and clinker (C) content in dierent size fractionsafter their intergrinding (mixture neness: 3890 cm2/g, limestonecontent: 20%).4. Hydration of Portland limestone cements Limestonecementscontaining0%,10%,20%and 35% w/w limestone were examined (samples C-45, CL10-4

31、5, CL-20-45 and CL-35-45 of Table 4). The properties of the studied cements are given in Table 4. Pastes were prepared by mixing solid and carbon dioxide-free distilled water in polyethylene vials subjectedto rotation from time to time. The water-to-cement ratio used is 0.3. After periods of 1, 2, 7

32、 and 28 days, the samples were dried in vacuum for 24 h and subjected to X-ray difraction. Thermogravimetric analysis (TGA) was used for the determination of non-evaporable water and calcium hydroxide content in dried cement pastes, using a TA Instruments Thermal Analyst 3000. The samples (_50 mg) w

33、ere heated over the range 20-900 at a constant rate of 15/min in an atmosphere of carbon dioxide- free nitrogen, owing in 90 cm 3/min. Table 5 shows the hydration products in the C-45 and CL-35-45 pastes. In C-45 pastes, ettringite is gradually transformed into monosulfate. In CL-35-45 pastes, the f

34、ormation of ettringite is delayed and monocarboalu- minateispreferablyformedinsteadofmonosulfate. Calcium aluminate hydrates (3CaO·Al2O3·Ca(OH)·18H2O and Ca2Al2O5·8H2O)aredetectedinC-45 pastes but not in limestone pastes, probably because of the dilution of the samples by limesto

35、ne.Table 4Composition and properties of Portland limestone cementsaLimestone cement: CL-c-t, C: clinker, L: limestone, c: limestone (%), t: grinding time (min).bn: Uniformity factor of RR distribution.Fig. 2. Inuence of limestone content on cement strength development(grinding time: 45 min).Concerni

36、ng the CH and non-evaporable water de- terminations(Table6),thehighercontentofbound water, in the pastes made from limestone cements, in- dicatesthatlimestoneimprovestheclinkerreactivity and the exploitation of its hydraulic potential. This ef- fect may be related to the structure modification of th

37、e hydration products as well as to the nucleating action of the finely ground limestone. The increase of Ca(OH )2content in pastes of limestone cement indicates an acceleration of calcium silicates hydration, especially in cement containing 10% limestone.5. Properties of limestone cement concreteThe

38、 composition and properties of the tested cements are given in Table 7. Portland limestone cements were producedbyintergrindingofclinker,limestoneand gypsum in a pro-pilot plant ball mill of 5 kg capacity. The cements LC1-LC4 contain 0%, 10%, 15% and 20% limestone,respectively,andhavethesame28dcom-

39、2 pressive strength (48-51 N/mm , strength class 42.5R of EN 197-1). The cement LC5 contains 35% limestone (32.5R of EN 197-1). The concrete production was carried out in a mixer of 50 l capacity. The mix proportions and the aggregate grading are given in Table 8. Theconcretepropertiesofthetestedcem

40、entsare giveninTable9.Themixeswithlimestonecement,althoughtheirhigherfineness,indicateasatisfactory workability. The slump of the mixes was in the range 110-130 mm (class S3 of EN 206). A plasticizer (Poz- zolith 390N) was used in concrete containing cement with 35% limestone (LC5). Concerning the c

41、ompressive strength, all the mixes belong to the class C20/25 of EN 206.Table 5Hydration products in samples C-45 and CL-35-45Table 6Non-evaporable water andCa(OH )2 content in limestone cement pastesTable 7Characteristics of the tested cementsTable 8Concrete mix proportions and aggregate gradingaPl

42、asticizer (Pozzolith 390N).Table 9Concrete properties6. Corrosion behavior of limestone cement mortar The cements of Table 7 have been used for the rela- tive tests. The W =C ratio was 0.50 and the calcareous sand:cement ratio was 3:1. Prismatic specimens (80 _80 _ 100mm 3)wereconstructedand fourcyl

43、indrical steel bars (12×100 mm 2) were embedded in each one. Each bar has a properly attached copper wire. Both, the top surface of all specimens and the part of steel bars which protrudes over the concrete, are covered with an epoxy glue to protect the bars from atmospheric corrosion.The speci

44、mens were partially immersed in a 3 wt% NaClsolution,uptoaheightof25mm,inorder to accelerate the corrosion process. After immersing all specimens in the corrosive solution, the following measurements were carried out: (a) gravimetric mass loss of the rebars after 9 and 12 months exposure, (b) mean c

45、arbonation depth, after 9 and 12 months, using phe- nolphthalein indicator, anointed across a vertical section of the specimen and (c) porosity of the specimens, after 9 months exposure, using a Carlo Erba 2000 Hg porosi- meter. It must be noted that the advanced investigation of steel rebars corros

46、ion with strain gauges is the subject of a future study 36. Fig. 3 presents the mass loss of rebars (average value of four specimens), expressed as mg=cm 2 of surface of the rebars. There is an explicit decrease of corrosion in specimens with limestone. The mass loss of rebars decreases as the limes

47、tone content increases up to 20%. It must be noticed that the corrosion rate of LC4 is three timeslowerthanLC1mg/cm 2monthagainst 0.093 mg/cm 2 month). The mass loss of specimens with 20% and 35% limestone is the same, in the frame of statistical analysis. Concerning the carbonation depth, all types

48、 of Portland limestone cements used did not show any carbonationafterexposuretimesof 9 and 12 months.The Portland cement specimen had a carbonation depth of 3- 5 mm. In addition, the specimens with limestone had lower porosities compared with those of the Portland cement specimen (LC1: 15.3%, LC2: 1

49、1.6%, LC3: 12.2%, LC4: 12.5%, LC5: 13.1%). Thus, the corrosion behavior of the limestone cement concrete may be attributed to the lower total porosity and the negligible carbonation depth. The above phe- nomena lead to a significant reduction of the corrosion potentialresultinginreducedmasslossofthe

50、used rebars.Fig. 3. The effect of the limestone content on the mass loss of rebars.7. Conclusions The followingconclusions canbedrawn fromthe present study: The particle size distribution of the Portland lime- stone cements, as well as the fineness of clinker and limestone, is strongly connected wit

51、h the limestone content and the fineness of the cement. The limestone cements indicate satisfactory strength andgenerallydemandlesswaterthantherelative pure cements. The limestone addition improves the clinker reactiv- ity and the exploitation of its hydraulic potential. The Portland limestone cemen

52、ts indicate competitive concrete properties and improve the durability of the concrete.References1 Sparker S, Ghosh S. Mineral admixtures in cement and concrete.1st ed. India: ABI Books Private Limited; 1993.2 Baron J, Dourve C. Technical and economical aspects of theuse of limestone ller additions

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57、r; 1991. p. 10724.11 Ingram K, Daugherty K. Limestone additions to Portland cement:uptake, chemistry and effects. In: Proceedings of the 9th International Congress on the Chemistry of Cement, New Delhi, vol. III.1992. p. 1806.12 Ingram K, Poslusny M, Daugherty K, Rowe D. Carboaluminatereactions as i

58、nuenced by limestone additions. In: Kligger P,Hooton D, editors. Carbonate additions to cement. ASTM STP,vol. 1064. Philadelphia: ASTM; 1990. p. 1423.13 Klemm W, Adams L. An investigation on the formation ofcarboaluminates. In: Kligger P, Hooton D, editors. Carbonateadditions to cement. ASTM STP, vo

59、l. 1064. Philadelphia: ASTM;1990. p. 6072.14 Tsivilis S, Kakali G, Chaniotakis E, Souvaridou A. A study onthe hydration of Portland limestone cement by means of TGA.J Thermal Anal 1998;52:86370.15 Kakali G, Tsivilis S, Aggeli E, Bati M. Hydration products ofC3A, C3S and Portland cement in the presence of CaCO3. CemConcr Res 2000;30(7):10737.16 Bona