research article sustainable use of tepetate composite in...

Hindawi Publishing CorporationAdvances in Materials Science and EngineeringVolume 2013 Article ID 806387 6 pageshttpdxdoiorg1011552013806387

Research ArticleSustainable Use of Tepetate Composite in Earthen Structure

T Loacutepez-Lara Juan Bosco Hernandez-Zaragoza Jaime Horta Eduardo Rojas GonzalezCarlos Lopez-Cajun and Gerson Ramirez

Postgraduate Division Faculty of Engineering Autonomous University of Queretaro Cerro de las Campanas SNColonia Ninos Heroes 76010 Queretaro QRO Mexico

Correspondence should be addressed to T Lopez-Lara lolteuaqmx

Received 20 March 2013 Accepted 18 June 2013

Academic Editor Mohd Sapuan Salit

Copyright copy 2013 T Lopez-Lara et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

One of the best indicators for construction sustainability is the use of earthy local materials which are completely recyclables andsavers of energy during their life cycle Tepetate is an underestimated earth-natural material vast and economic used only in acompacted form in backfills for layers of low resistance in pavements and platforms of buildings This volcanic soil named indifferent ways in several countries is found in the central region of Mexico Its resistance as compacted material is very low ofthe order of 008MPa In this work an improved sustainable-tepetate composite using CaOH is presentedThis research includesthe determination of mechanical properties as well as the physicochemical characterization of the sustainable-tepetate compositebehavior It can be concluded that the strength of the proposed composite increases significantly immediately after treatment andwith time X-Ray Diffraction shows that all the mineralogical phases prevail in the natural tepetate and only a new phase appeared(calcite) which increases with timeThis and the reaction of CaOHwith clay content are very likely associated with the continuousstrength increase of the composite

1 Introduction

Construction based on earthy materials is the most impor-tant since these are natural sustainable and plenty in anyregion of the world Unfortunately the applications of anearthy material in general depend on their mechanicalproperties in their pure natural form This fact makes themof limited applications which leads to be used only as fillsin platforms One example of this kind of materials is thetepetate However there is a potential of being used as acomposite via the use of other economical and sustainablematerials for constructions such as the CaOH Indeed CaOHis a material being used from ancient timesThere are severalantique constructions as bridges castles and aqueducts builtwith stones and CaOH as joining material These construc-tions have lasted for centuries and they still can be seennowadays The previous shows their long useful life

Moreover CaOH has a wide field of applications both inindustry (paper paints etc) and construction (it decreasessoils expansion and increases strength on pavements) Itis also used as fertilizer metallurgy water treatment glassmanufacture and so forth

In this work CaOH was used to improve the mechanicalproperties of natural tepetate This is an economic and vastvolcanic soil used in construction only as backfill material

2 Background

The use of earth on site as a building material saves manufac-turing cost time energy environmental pollution and trans-portation cost Earth can also be used in the constructionof low cost sustainable houses which is significantly cheaperthan using conventional bricks Selected soil (sand and clay)is mixed with water to the correct proportions and thenplaced in a hydraulic or hand operated compressing machineto produce compressed blocks which after curing is used forbuilding walls [1 2]

Tepetates have been reported in several countries mainlyin Latin America They have been denoted with differentnames such as silcrete in the USA talpetate in Nicaraguahardpan duripan and cangahua in Colombia and Ecuadorcancagua moromoro tosca and nadis in Chile hardpan inPeru and kora and masa in Japan [3]

2 Advances in Materials Science and Engineering

Tepetate is a word derived from the Nahuatl tepetlatlwhose root tetl means stone and petlatl petate Literally ithas been translated as ldquostone-petaterdquo ldquostone-likerdquo or ldquosoft-rockrdquo For the aztecs this word was included within theirclassification of materials of a type of soil for agriculturehard to work [4] However when the Spaniards arrived toMexico the word tepetate was synonymous of agriculture-useless because of its low quality [5]

In Mexico there exists a great amount of materialsdenoted as tepetates These occupy approximately 30 of thesurface of the whole country [6 7] either on the surface or inthe first meter deep [8] Tepetates are interstratified volcanicbanks including paleosoils of different nature characterizedby horizontal boundaries andwell defined between the layersTepetates of the Mexican central plateau have been describedas massive compacted and hard natural formations andcemented for several chemical agents including clays andsilicates [3] Tepetates classification has been based on thetype of cementing substance When the cementing substanceis mainly silica (SiO

2) the tepetates are denoted ldquoduri-

panrdquo when is calcium carbonate (CaCO3) the tepetates are

denoted ldquopetrocalcicrdquo type when is calcium sulfate (CaSO4)

they are denoted ldquopetrogypsicrdquo type when are salts theyare denoted ldquopetrosaltrdquo type when is iron they are denotedldquopetroferricrdquo type and when is clay they are denoted ldquofragi-panrdquo type Tepetates are originated basically from volcanicmaterials that have been cemented or compacted as conse-quence of three main processes (1) consolidation of mineralparticles provoking compaction (2) nature of the pyroclasticmaterials consolidated at the instant of being deposited(3) hardening by pedologic (sedimentary) processes whichproduce cementing substances in solution [6 7]

Several works onMexican tepetates have been reported inthe literature Most of them have been based in their physicaland chemical characterization [9ndash11] In most of those itreports is assessed that tepetate is a matrix composed of sandlime and small percentages of clays However once in a whilethey can exhibit high content of claysThis variability leads toa problem for work-rehabilitation of tepetates for each textu-ral type generates an independent physical and mechanicalbehavior Clearly this fact requires a specific investigationSome of their reports were based on micromorphologicalcharacteristics [12] which have a distribution related to grossand fine particles simple porphyritic and morphology ofpeds in subangular blocks suggesting a reorganization of thebasal mass There are also reports focused on the cementingsubstance identification the use of soil and its ecologicalsignificance [6 7]

Some authors have made reference to the relief climateand pedologic origin of tepetates [13 14] As a matter offact it has been determined that the secondary hardeninghappens under template or semiarid conditions this climatecondition allows the liberation of compounds The liberatedcompounds are lixiviated and deposited and then they actas cementing substance (free silica calcium carbonate) inthe soil These are particularly efficient if in the matrixof the horizon where they are deposited are absorbed byclay Tepetates are formed preferably in subhumid climates(annual precipitation less than 800mm) characterized for a

dry season lasting from four to six months [14] where ingeneral evapotranspiration is greater than the precipitation

There are also a great amount of studies about its agro-logical properties (important for agronomy) Indeed sincethe pre-Hispanic age there have been some attempts for usingthem in agriculture by breaking themup and fertilizing them[15]This is so because they have a very low content of organicmatter nitrogen and phosphorous which makes it difficultfor using them in agricultural production [16] Some studieshave been on tepetate taxonomy for example [17] reportedthat in the lower level known as generic there were kindsof soils that can be located in the group of work soils as wellas in the nonwork soils This double inclusion is exemplifiedwith the materials named as tepetates About its classificationand geological origin [6 18] tepetates are originated fromold deposits of volcanic ashes deposited in situ or reworkedwhich were subjected to both processes namely diagenesis(hydroconsolidation) and pedogenesis that contributed to itscompaction andor cementation

On the other hand tepetates below soils produce litholog-ical discontinuity that block the water infiltration and favorthe lateral leakage marking a surface where slides are proneAs well tepetate could favor erosion and prevent aquifersreloading [19]

In 1996 while the III International Symposium of Hard-ened Volcanic Soils was celebrated at Quito Ecuador it wasproposed to characterize tepetates as a hardened horizonof volcanic origin whose material is basically composed ofpyroclastic materials or fluids or else as degraded volcanicsoils

Based on research done for several authors [9ndash11] it ispossible to infer that independently of its origin tepetatesalways show common physical mechanical and chemicalproperties among them Its compaction or cementationshould be highlighted which are reflected in high apparentdensities (1667ndash1863 KNm3) low porosity (from 13 to24) and its hydraulic conductivities and holding lowhumidity These characteristics limit significantly the fastincorporation of primary plants and generate a constant soilerosion

Llerena [20] and Garcıa [21] considered tepetates ofthe Mexican Valley as pumite fragments of the Terciary orCenozoic in process of weathering Valdes [22] mentionedthat tepetates of the Mexico were formed due to the alluvialsediments that lately were consolidated Rodrıguez et al[23] noticed that the results reported by the aforementionedauthor lack sufficient precision and left questions about thehardened layers concluding that tepetates may have diverseorigins

Zebrowski [3] states two geological processes for explain-ing the horizons hardening as follows

(A) Simple consolidation-compaction or by the hydro-consolidation of volcanic materials transported by the waterIn both cases there always exists an increase of the apparentdensity material a greater hardness and consequently adecrease of porosity

(B) Hardening of volcanic materials at the instant of theirdeposit and posterior cooling (pyroclastic flows) is another

Advances in Materials Science and Engineering 3

These natural deposits called tepetate in Mexico havevery low permeability and the overlying soil erodes rapidlywhen cultivated Unconfined compression varied from 029to 157MPa and the mean was 242MPa The strongestmost indurated tepetate appears to occur when disseminatedcarbonates combine with silica as cementing substances [24]The reported properties are circumstantial and depend on thegeological consolidation and type of cementing substance

As construction material the properties of tepetatesshow a wide range of values thus making it less reliable ashomogeneousmaterial for construction Adding it has a verylow strength as construction material [25] The propertiesof Tepetate depend on the volcanic origin of this materialmainly through phreatomagmatic eruptions As constructionmaterial 80 of the tepetates are classified as silty sandaccording to the Unified System of Soil Classification with noplasticity [26]

About problematic soils used in embankments for sus-tainable pavements there is a study for bituminous sandmaterials where their high bitumen content makes oil sandmaterials problematic for field operations [27] Then aboutexpansive soils there is a study on their engineering propertiesas subgrade when stabilized by using different percentage ofhydrated lime on thickness of pavement structural systemThe results suggest that the highly strength lowest swellingand small thickness of pavement were determined with anoptimum percentage of lime content of 6 [28]

CaOH is a natural linking material in the preparation ofmortars for construction Indeed their usage goes back toancient times Developed countries specify for constructionin seismic zones the compulsory use of CaOH in mortarsbecause of their unique features of adherence and strengthfor sustaining diagonal tensions

Up to the industrial revolution and the cement discoveryin 1824 at Portland UK CaOH had been the main linkfor construction in mortars stuccos and paints Due to thelimited facility of transportation constructors applied thelocal material but they knew a wide spectrum of tricks forcorrecting the effects of each of the found CaOH and produc-ing the mortars with the required quality in each applicationcase such as the control of speed for solidification hardnessand the degree of waterproofing [29]

Lime treatment in clay soils can be explained by twotypes of chemical reactions that occur when lime is addedto a wet soil short-term reactions known as soil improve-ment or modification consisting of cation exchange andflocculation and the long-term reaction known as stabiliza-tionsolidification the pozzolanic activity During the cationexchange the highly alkaline environment produced by theaddition of lime causes silica and alumina to be dissolvedout of the structure of the clay minerals and to combinewith the calcium to produce new cementitious compoundscalcium silicate hydrates calcium aluminate hydrates andcalcium aluminosilicate hydrates The calcium hydrosilicatescontribute substantially to the strength of the stabilized soilmaterial and are of varying composition These reactionscontribute to flocculation by bonding adjacent soil particlestogether and strengthen the soil with curing time [30 31]

3 Experimental Methodology

31 Soils Samplings Tepetate was taken from one of the largeactive banks of Queretaro QROMexico It should be pointedout that this location was selected because tepetate was beingused for backfills in residential areas and also as layers for baseor subbase of pavements The place is known as ldquoMompanirdquohaving geographical coordinates latitude 20∘39101584069010158401015840N lon-gitude 100∘281015840296110158401015840W and a height of 1905m above sea levelThe CaOH used was of the commercial type

32 Procedure After extracting the material from ldquoMom-panirdquo the index and mechanical properties were determinedfollowing the procedure set by the American Society forTesting and Materials (ASTM)

(i) gradation (size of aggregates) [32](ii) liquid limit plastic limit and index limit (material

plasticity) [33](iii) classification by the Unified System for Soil Classifi-

cation (it defines soil type) [34](iv) proctor Standard Compaction (it determines the

maximum dry density and optimum humidity of thematerial for obtaining the greater strength) [35]

(v) unconfined compressive strength (material strength)[36]

Then the physicomechanical behavior of the sustainable-tepetate composite using CaOH was studied by performingthe tests listed as follows

(i) proctor Standard Compaction [35](ii) unconfined compressive strength at different ages

[36]

Finally the physicochemical characterization of naturaltepetate and the sustainable-tepetate composite was done viaX-Ray Diffraction

4 Results

41 Index and Mechanical Properties of the Natural Tepetateunder Study Gradation was made by the dry mechanicalmethod It was determined using sieve analysis With thismethod the particles distribution can be quantified startingfrom the larger ones (75 microns retained in sieve N∘200)[32]The results of soil gradation were graves (2322) sands(4255) and fines (3423)

The plasticity properties (Liquid Limit LL Plastic LimitPL and Plastic Index PI) were determined for the bank ofselected material [33]The values obtained were LL = 3245PL = 3138 and PI = 107 The soil classification wasobtained by the plasticity chart From this one had that thefines are limes of low plasticity (ML)Then with the plasticityproperties and the gradation (455 sands and 3236 offines) the soil can be classified as a silty sand (SM) [34]Since tepetate is a material placed and compacted in theconstruction site its ideal compaction was determined via


Table 1 Materials standard compaction

Material Maximum dry unitweight (KNm3)

Optimummoisture ()

Natural tepetate 1267 285Tepetate-CaOH 2 1247 275Tepetate-CaOH 4 1255 28Tepetate-CaOH 6 1273 278Tepetate-CaOH 8 1294 265Tepetate-CaOH 10 1279 275Tepetate-CaOH 12 1281 285Tepetate-CaOH 15 1309 265Tepetate-CaOH 20 1319 255

Proctor Standard test [35]Themaximum specific dry weightwas 1267 KNm3 with an optimum humidity of 285 Thestrength of natural tepetate was measured to 0 days and was0082MPa [36]

42 Properties of the Sustainable-Tepetate Composite

421 Proctor Standard Compaction The Proctor Standardtest [35] was made for the sustainable-tepetate compositewith different percentages of CaOH (2 4 6 8 1012 15 and 20 with respect to the soil dry weight)These are shown in Table 1 From that table it can be seenthat in general with the increase of CaOH the optimumhumidity tends to decrease and its maximum specific-dry weight increases slowly Moreover it can be seen thatthe increment of CaOH disintegrates tepetate easing andincreasing the compaction The optimum moisture of mostof the composites is between 26ndash285 and from 1247 to1318 KNm3 of maximum dry unit weight

422 Unconfined Compression Strength of Sustainable-Tepetate Composite The Unconfined Compression StrengthStandard test [36] was made for the sustainable-tepetatecomposite with different percentages of CaOH Probesof sustainable-tepetate composites were compacted fordifferent CaOH percentages For this their dry unit weightand optimum humidity obtained by the Proctor standardwere applied Probes were prepared for several periods oftime namely for 0 7 14 28 42 56 70 112 and 126 daysas shown in Table 2 and Figure 1 Tepetate strength test wasmade only to 0 days and the result was 008MPa

From Figure 1 it is apparent that the strength increaseswhen the amount of CaOH in the composite also increasesThe increase of strength with time is also noticeable and thesame happens with clays [37] However there is an optimumamount (10) of CaOH leading to themaximum strength Astime goes on the composite strength increases significantlyreaching to 294MPa at 28 days and up to 421MPa at 56 daysstabilization timeThe increase of resistance of the tepetate isvery likely for its clay contentThe treatment of clay with limeincreases its resistance with the time due to the formationof calcium silicate hydrates calcium aluminate hydrates and

000100200300400500600

0 20 40 60 80 100 120 140

Resis

tanc

e (M

pa)

Time (days)

Tepetate-CaOH 2Tepetate-CaOH 4Tepetate-CaOH 6Tepetate-CaOH 8


Figure 1 Strength time variation of the sustainable-tepetate com-posite

calcium aluminosilicate hydrates These reactions contributeto flocculation by bonding adjacent soil particles together andstrengthen the soil with curing time

43 X-Ray Diffraction (XRD) X-Ray Diffraction was donewith a diffractometer Bruker D8-Advance at 30KV and30mA Samples of natural tepetate and the sustainable-tepetate composite at 15 and 30 days were analyzed foridentifying minerals at the outset and those formed aftersome time

Natural Tepetate X-Ray Diffraction to natural tepetate wasdoneThe study shows that several minerals as the halloysitehematite and quartz can be identified The halloysite is atype of clay with plasticity much greater than the kaolin-ite Hematite is a product of contact metamorphism andiron formations and is a common cementing substance insedimentary rocks frequently abundant in weathered ironminerals This is an outcome of the goethite decompositionwhich was found in the composite

Quartz was another mineral found Actually this is themain component of sands [6] and was also identified at thetepetate XRD

Sustainable-Tepetate Composite at 15 Days The diffractogramof better sustainable-tepetate composite (10 CaOH) at 15days shows that all the phases of the natural tepetate arepresent among them quartz hematite and halloysite (fromwhite to light gray) but a new phase (calcite) appeared asresult of the reaction of the CaOH with water

The use of CaOH with expansive-clay soils a treatmentapplied generally to inhibit volumetric instability showedan increase of strength Additionally it is known that sucha mixture generates calcite formation which increases withtime [37] Therefore it is very likely that the calcite isresponsible of the strength composite

The light gray and white colors of the tepetate seem to beoriginated by the absence of weathering of the original rock ofgray and white colors deposits of CaCO

3 arising from salts

or as result of iron removal leaving great amount of mineralsrich in SiO

2as quartz feldspar and kaolinite [6 7]


Table 2 Resistance of sustainable-tepetate composite in time

Resistance material (MPa) Time (days)0 7 14 28 42 56 70 112 126

Tepetate-CaOH 2 009 046 053 027 030 034 031 033 045Tepetate-CaOH 4 050 118 121 150 166 178 172 192 198Tepetate-CaOH 6 033 095 129 185 235 283 264 266 273Tepetate-CaOH 8 038 122 152 217 302 386 358 341 417Tepetate-CaOH 10 044 136 182 297 354 414 412 483 404Tepetate-CaOH 12 047 124 178 288 351 403 400 444 397Tepetate-CaOH 15 036 109 146 279 344 393 391 410 396Tepetate-CaOH 20 032 093 122 230 345 405 380 391 385

Sustainable-Tepetate Composite at 30 DaysThe diffractogramof the sustainable-tepetate composite (10 CaOH) at 30 daysshows that all the phases of the natural tepetate are presentbut the calcite shows an increment with respect to 15 daysbecause the deflection or peak of the calcite grows in thediffractogram [37]

5 Conclusions

The strength of the natural tepetate was 008MPa It wasconstituted by graves (2322) sands (4255) and fines(3423)

Themechanical behavior of the sustainable-tepetate com-posite was improved with a maximum 10 of CaOH Indeedwith this percentage of CaOH the maximum strength wasobtained After this percentage the strength showed noimprovement Additionally a significant increase of strengthwas recorded as time went on In fact at 28 days the strengthwas 294MPa whereas at 56 days time for stabilization thestrength was 421MPa Thus it is apparent that the inclusionof CaOH produced an optimum strength of the tepetateby improving their mechanical properties in structures ofcompacted soils This methodology creates a new sustainablecomposite using tepetate

From the X-Ray Diffraction it was inferred that thenatural tepetate was constituted mainly by halloysite quartzand hematite These correspond to the gradation of soil witha better definition (weathered sands and halloysite clay)Since there was presence of iron minerals (hematite) andclay (halloysite) the tepetate could be classified as of thepetroferric type with some halloysite clay In the sustainable-tepetate composite with CaOH all the phases of naturaltepetate appeared However a new phase formed (calcite)which increased with time could be associated very likelywith the increase of strength of the composite with timeAt the same time the reactions of CaOH with clay contentcontribute to flocculation by bonding adjacent soil particlestogether and strengthen the soil with curing time

The sustainable-composite tepetate offers an alternativeconstruction material because of local construction materialbeing lasting resistant and economical of low consumptionenergy in its preparationMoreover it is one hundred percentrecyclable and thus can be used for reinforced platforms or forblock elements

References

[1] M S Zami and A Lee ldquoUsing earth as a building material forsustainable low cost housing in ZimbabwerdquoTheBuilt amp HumanEnvironment Review vol 1 pp 40ndash55 2008

[2] R Sangeeta and C Swaptik ldquoEarth as an energy efficientand sustainable building materialrdquo International Journal ofChemical Environmental amp Biological Sciences vol 1 no 2 pp257ndash261 2013

[3] C Zebrowski ldquoLos suelos volcanicos endurecidos de AmericaLatinardquo Terra Latinoamerica vol 10 pp 15ndash23 1992

[4] Ch Gibson Los Aztecas Bajo El Dominio Espanol 1519ndash1810Siglo XXI Coyoacan Mexico 13 edition 1996

[5] C A Ortiz-Solorio Los levantamientos etnoedafologicos [PhDthesis] Colegio de Postgraduados Instituto de Recursos Natu-rales Montecillo Mexico 1999

[6] D Flores-Roman A Gonzalez-Velazquez J R Alcala-Martınez and J E Gama-Castro ldquoLos tepetatesrdquo Revista DeGeografıa vol 3 no 4 pp 37ndash42 1991

[7] D Flores-Roman A Gonzalez-Velazquez J R Alcala-Martınez and J E Gama-Castro ldquoDuripans in the subtropicaland temperate subhumid climate of the Trans-Mexico VolcanicBeltrdquo Revista Mexicana De Ciencias Geologicas vol 13 no 2pp 228ndash239 1996

[8] E G GuerreroM J L Luna andO E Caballero ldquoDistribucionde los tepetates de la Republica Mexicana escala 14 000 000rdquoTerra vol 10 pp 131ndash136 1992

[9] G Miehlich ldquoFormation and properties of tepetate in thecentral highlands of Mexicordquo Terra vol 10 pp 137ndash144 1992

[10] H D Pena M E Miranda C Zebrowski and M H AriasldquoResistencia de los tepetates de la vertiente occidental de laSierra Nevadardquo Terra vol 10 pp 164ndash177 1992

[11] D J Etchevers M Rosa Lopez-Claude C Zebrowski and DPena ldquoCaracterısticas quımicas de tepetates de referencia de losestados de Mexico y Tlaxcala Mexicordquo Terra vol 10 pp 171ndash182 1992

[12] R Hessmann ldquoMicromorphological investigations on ldquotepe-taterdquo formation in the ldquotobardquo sediments of the state of Tlaxcala(Mexico)rdquo in Suelos Volcanicos Endurecidos vol 10 of Terra pp145ndash150 1992

[13] A Geissert ldquoLos tepetates de Xalapa VeracruzMexico relacioncon el relieve modelado actual y esquema cronologicordquo Terravol 10 pp 221ndash225 1992

[14] D Dubroeucq P Quantin and C Zebrowski ldquoLos tepetatesde origen volcanico en Mexico Esquema Preliminar de clasi-ficacionrdquo Terra vol 7 pp 1ndash13 1989


[15] S Rodriguez-Tapia C A Ortız-Solorio C Hidalgo-MorenoandM C Gutierrez-Castorena ldquoLos tepetates de la ladera oestedel cerro Tlaloc saprolita sin endurecimiento pedologicordquoTerra Latinoamerica vol 22 no 1 pp 11ndash21 2004

[16] J D Alvarez-Solıs R Terrera-Cerrato and J D Etchevers-Barra ldquoActividad microbiana en tepetate con incorporacion deresiduos organicosrdquo Agrociencia vol 34 no 5 pp 523ndash5322000

[17] B J Williams and C A Ortiz-Solorio ldquoMiddle American folksoil taxonomyrdquo Annals Association of American Geographersvol 71 no 3 pp 335ndash358 1981

[18] T J Nimlos and C Ortiz-Solorio ldquoTepetate the rock matrdquoJournal of Soil amp Water Conservation vol 42 no 2 pp 83ndash861987

[19] J E Gama-Castro E McClung de Tapia E Solleiro-Rebolledoet al ldquoIncorporation of ethnopedological knowledge in thestudy of soils in the Teotihuacan Valley Mexicordquo Eurasian SoilScience vol 38 no 1 pp S95ndashS98 2005

[20] L D Llerena El distrito de conservacion del suelo y agua deChapingo Mexico [PhD thesis] Escuela Nacional de Agricul-tura Chapingo Mexico 1947

[21] E A Garcıa Estudio de los suelos tepetatosos y las posibilidadesde recuperacion agrıcola [PhD thesis] Escuela Nacional deAgricultura Chapingo Mexico 1961

[22] L A Valdes Caracterısticas morfologicas y mineralogicas de lossuelos de tepetate de la Cuenca de Mexico [MS thesis] Colegiode Postgraduados Escuela Nacional de Agricultura ChapingoMexico 1970

[23] S Rodrıguez M C Gutierrez-Castorena C Hidalgo and CA Ortiz-Solorio ldquoCIntemperismo en Tepetates y en cenizasvolcanicas y su influencia en la formacion de Andisolesrdquo Terravol 17 pp 97ndash108 1999

[24] T J Nimlos ldquoThe density and strength of Mexican tepetate(duric materials)rdquo Soil Science vol 147 no 1 pp 23ndash27 1989

[25] T Lopez-Lara J B Hernandez-Zaragoza J Horta-Rangel ERojas C Lopez-Cajun and D Rosales-Hurtado ldquoTepetate asconstructionmaterialrdquo Journal ofMaterials in Civil Engineering2012

[26] T Lopez-Lara J B Hernandez-Zaragoza J Horta-RangelE Rojas and D Rosales-Hurtado ldquoGeocharacterisation ofldquoTepetatesrdquordquo European Journal of Environmental and Civil Engi-neering 2013

[27] J Anochie-Boateng E Tutumluer and S H Carpenter ldquoCasestudy dynamic modulus characterization of naturally occur-ring bituminous sands for sustainable pavement applicationsrdquoInternational Journal of Pavement Research and Technology vol3 no 6 pp 286ndash294 2010

[28] A A M Adam I A Ibrahim A J Alhardllo A M Hadi andMY Ibrahim ldquoEffect of hydrated lime on behavior of expansivesoil as subgrade of flexible pavement structural systemrdquo inSustainable Construction Materials S Wu L Mo B Huangand B F Bowers Eds pp 64ndash76 American Society of CivilEngineers 2012

[29] O F Arredondo Estudio De Materiales VI Ceramica Y VidrioInstituto Eduardo Torroja de la Construccion y el CementoMadrid Spain 9nd edition 1980

[30] J A Lasledj andM Al-Mukhtar ldquoEffect of hydrated lime on theengineering behavior and the microstructure of highly expan-sive clayrdquo in Proceedings of the 12th International conference ofInternational Association for Computer Methods and Advancesin Geomechanics pp 3590ndash3598 Goa India 2008

[31] J Ninov I Donchev A Lenchev and I Grancharov ldquoChemicalstabilization of sandy-silty illite clayrdquo Journal of the University ofChemical Technology and Metallurgy vol 42 no 1 pp 67ndash722007

[32] Standard Test Method for Particle-Size Analysis of Soils ASTMD422-63 Annual Book of ASTM Standards 2007

[33] Standard Test Methods for Liquid Limit Plastic Limit andPlasticity Index of soils ASTMD4318-10Annual Book of ASTMStandards 2010

[34] Standard TestMethod for Classification of Soils for EngineeringPurposes ASTM D 2487-93 Annual Book of ASTM Standards1993

[35] Standard Test Methods for Laboratory Compaction Charac-teristics of Soil Using Standard Effort (12400ft-lbfft3(600kN-mm3)) ASTM D698-00a Annual Book of ASTM Standards2000

[36] Standard Test Method for Unconfined Compressive Strengthof Cohesive Soil ASTM D2166-00 Annual Book of ASTMStandards 2000

[37] T Lopez-Lara J Horta-Rangel J B Hernandez-Zaragozaand V M Castano ldquoProperties of waste soil-hydrated limecompositerdquoMechanics of Time-DependentMaterials vol 10 no2 pp 155ndash163 2006

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Tepetate is a word derived from the Nahuatl tepetlatlwhose root tetl means stone and petlatl petate Literally ithas been translated as ldquostone-petaterdquo ldquostone-likerdquo or ldquosoft-rockrdquo For the aztecs this word was included within theirclassification of materials of a type of soil for agriculturehard to work [4] However when the Spaniards arrived toMexico the word tepetate was synonymous of agriculture-useless because of its low quality [5]

In Mexico there exists a great amount of materialsdenoted as tepetates These occupy approximately 30 of thesurface of the whole country [6 7] either on the surface or inthe first meter deep [8] Tepetates are interstratified volcanicbanks including paleosoils of different nature characterizedby horizontal boundaries andwell defined between the layersTepetates of the Mexican central plateau have been describedas massive compacted and hard natural formations andcemented for several chemical agents including clays andsilicates [3] Tepetates classification has been based on thetype of cementing substance When the cementing substanceis mainly silica (SiO

2) the tepetates are denoted ldquoduri-

panrdquo when is calcium carbonate (CaCO3) the tepetates are

denoted ldquopetrocalcicrdquo type when is calcium sulfate (CaSO4)

they are denoted ldquopetrogypsicrdquo type when are salts theyare denoted ldquopetrosaltrdquo type when is iron they are denotedldquopetroferricrdquo type and when is clay they are denoted ldquofragi-panrdquo type Tepetates are originated basically from volcanicmaterials that have been cemented or compacted as conse-quence of three main processes (1) consolidation of mineralparticles provoking compaction (2) nature of the pyroclasticmaterials consolidated at the instant of being deposited(3) hardening by pedologic (sedimentary) processes whichproduce cementing substances in solution [6 7]

Several works onMexican tepetates have been reported inthe literature Most of them have been based in their physicaland chemical characterization [9ndash11] In most of those itreports is assessed that tepetate is a matrix composed of sandlime and small percentages of clays However once in a whilethey can exhibit high content of claysThis variability leads toa problem for work-rehabilitation of tepetates for each textu-ral type generates an independent physical and mechanicalbehavior Clearly this fact requires a specific investigationSome of their reports were based on micromorphologicalcharacteristics [12] which have a distribution related to grossand fine particles simple porphyritic and morphology ofpeds in subangular blocks suggesting a reorganization of thebasal mass There are also reports focused on the cementingsubstance identification the use of soil and its ecologicalsignificance [6 7]

Some authors have made reference to the relief climateand pedologic origin of tepetates [13 14] As a matter offact it has been determined that the secondary hardeninghappens under template or semiarid conditions this climatecondition allows the liberation of compounds The liberatedcompounds are lixiviated and deposited and then they actas cementing substance (free silica calcium carbonate) inthe soil These are particularly efficient if in the matrixof the horizon where they are deposited are absorbed byclay Tepetates are formed preferably in subhumid climates(annual precipitation less than 800mm) characterized for a

dry season lasting from four to six months [14] where ingeneral evapotranspiration is greater than the precipitation

There are also a great amount of studies about its agro-logical properties (important for agronomy) Indeed sincethe pre-Hispanic age there have been some attempts for usingthem in agriculture by breaking themup and fertilizing them[15]This is so because they have a very low content of organicmatter nitrogen and phosphorous which makes it difficultfor using them in agricultural production [16] Some studieshave been on tepetate taxonomy for example [17] reportedthat in the lower level known as generic there were kindsof soils that can be located in the group of work soils as wellas in the nonwork soils This double inclusion is exemplifiedwith the materials named as tepetates About its classificationand geological origin [6 18] tepetates are originated fromold deposits of volcanic ashes deposited in situ or reworkedwhich were subjected to both processes namely diagenesis(hydroconsolidation) and pedogenesis that contributed to itscompaction andor cementation

On the other hand tepetates below soils produce litholog-ical discontinuity that block the water infiltration and favorthe lateral leakage marking a surface where slides are proneAs well tepetate could favor erosion and prevent aquifersreloading [19]

In 1996 while the III International Symposium of Hard-ened Volcanic Soils was celebrated at Quito Ecuador it wasproposed to characterize tepetates as a hardened horizonof volcanic origin whose material is basically composed ofpyroclastic materials or fluids or else as degraded volcanicsoils

Based on research done for several authors [9ndash11] it ispossible to infer that independently of its origin tepetatesalways show common physical mechanical and chemicalproperties among them Its compaction or cementationshould be highlighted which are reflected in high apparentdensities (1667ndash1863 KNm3) low porosity (from 13 to24) and its hydraulic conductivities and holding lowhumidity These characteristics limit significantly the fastincorporation of primary plants and generate a constant soilerosion

Llerena [20] and Garcıa [21] considered tepetates ofthe Mexican Valley as pumite fragments of the Terciary orCenozoic in process of weathering Valdes [22] mentionedthat tepetates of the Mexico were formed due to the alluvialsediments that lately were consolidated Rodrıguez et al[23] noticed that the results reported by the aforementionedauthor lack sufficient precision and left questions about thehardened layers concluding that tepetates may have diverseorigins

Zebrowski [3] states two geological processes for explain-ing the horizons hardening as follows

(A) Simple consolidation-compaction or by the hydro-consolidation of volcanic materials transported by the waterIn both cases there always exists an increase of the apparentdensity material a greater hardness and consequently adecrease of porosity

(B) Hardening of volcanic materials at the instant of theirdeposit and posterior cooling (pyroclastic flows) is another


















[36]


4 Results






Optimummoisture ()







000100200300400500600

0 20 40 60 80 100 120 140

Resis

tanc

e (M

pa)

Time (days)



















5 Conclusions





References














































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




















[36]


4 Results






Optimummoisture ()







000100200300400500600

0 20 40 60 80 100 120 140

Resis

tanc

e (M

pa)

Time (days)



















5 Conclusions





References














































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






Optimummoisture ()







000100200300400500600

0 20 40 60 80 100 120 140

Resis

tanc

e (M

pa)

Time (days)



















5 Conclusions





References














































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials








5 Conclusions





References














































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials


































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



research article sustainable use of tepetate composite in...

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