The pH influence on the index properties of clays



Three clay sediments, concerning Pliocenic clay, Chaotic Complex clay and commercial kaolinic clay, have been studied in order to verify the pH influence on the index properties. The analysed clays have been mineralogically characterized in natural, conditions, and in modified pH conditions. This last procedure, obtained respectively by adding NH4OH or CH3COOH 1 mol., in a pH range between 4.5–11.3 has been carried out. To verify the different experimental conditions the C.E.C. of exchangeable cations as K+, Na+, Ca++ and Mg++, has been measured. The index properties obtained show a different behaviour of the three clays. The kaolin is not much affected only a limited WL% increase is recognizable when the pH decreases. The Chaotic complex clay evidence a considerable rise of the WL with the pH uncrease. In the Pliocenic clay the WL value increased with the pH. The described process can be related to the natural environment, connected also with various pollution phenomena.


Clay Debris Flow Kaolinite Kaolin Liquid Limit 

Influence du pH sur les propriétés des argiles


Trois sédiments argileux: une argile pliocène, une argile appartenant à un complexe argileux et une argile kaolinique du commerce ont été étudiés en vue de vérifier l'influence du pH sur leurs propriétés. Les argiles étudiées ont été analysées dans les conditions naturelles eet dans des conditions de pH modifié. Ce dernier processus, obtenu en ajoutant respectivement NH4OH ou CH3COOH conduit à des pH variant de 4,5 à 11,3. Pour vérifier les différentes conditions expérimentales, le C.E.C. des cations échangeables tels que K+, Na+, Ca++ et Mg++ a été mesuré. Les caractéristiques mesurées montrent que les trois argiles ont des comportements différents. Le kaolin est peu affecté, on ne constate, qu'une augmentation limitée de WL quand le pH diminue. L'argile du complexe argileux affiche une augmentation considérable du WL quand le pH augmente. Dans l'argile pliocène WL augmente moyennement en fonction du pH. Le processus décrit peut être relié à l'environnement naturel ainsi qu'à différents phénomènes liés à la pollution.


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  1. ASTM, 1976: Test for liquid limit of soils. Designation D423-66. Annual book of ASTM Standards. Part. 19. Philadelphia.Google Scholar
  2. BEAR FIRMAN (Ed.). 1964. Chemistry of the soil. Reinhold Publishing Corporation. New York, 2nd Ed.Google Scholar
  3. BUCKMAN H.O. and BRADY N.C., 1969: The nature and properties of soils. The McMillan Co., Toronto, 653 p.Google Scholar
  4. CASAGRANDE A., 1940: The structure of clay and its importance in foundation engineering, in contributions to soil mechanisms, 1924–1940, Boston Soc. Civil Engrs. pp, 72–125.Google Scholar
  5. COTECCHIA V., FEDERICO A. and TRIZZINO R., 1982: Microtessiture di sedimenti argillosi. Esperimenti su kaolinite e bentonite ed esempi di sedimenti argillosi dell'Italia meridionale. Geol. Appl. Idr., v. 17, pp. 53–78.Google Scholar
  6. CRONEY D. and COLEMAN J.D., 1954: Soil structure in relation to soil suction (PF). J. Soil Sci., v. 5, pp. 75–84.CrossRefGoogle Scholar
  7. DAWSON R.F., 1960: Investigation of the liquid limit test on soils. Paper on soils, 1959 Meetings ASTM, Special Technical Publication No. 254, pp. 190–195.Google Scholar
  8. GORI U., 1991: Laboratory vane test: qualitative relationships between peak and residual shear strength of clays. IX PCSMFE, Chile, v. 1, pp. 501–514.Google Scholar
  9. MALESANI P. and MANETTI P., 1970: Proposta di classificazione di sedimenti clastici. Mem. Soc. Geol. It., v. 9.Google Scholar
  10. MICHAELS A.S., 1952: Altering soil-water relationships by chemical means. Proc. Mass. Inst. Tech. Conf. Soil Stability, Cambridge, pp. 59–67.Google Scholar
  11. MITCHELL J.K., 1956: The fabric of natural clays and its relations to engineering properties. Highway Res. Board Proc., 35 (Natl. Acad. Sci. Natl. Research Council Publ., 426), pp. 693–713.Google Scholar
  12. MITCHELL J.K., 1976: Fundamentals, of soil behaviour. New York: Wiley.Google Scholar
  13. O'BRIEN N.R., 1971: Fabric of kaolinite and illite floccules. Clay and Clay Minerals, v. 19, pp. 353–359.CrossRefGoogle Scholar
  14. OSIPOV Y.B., VAITEKUNENE A.I., SOKOLOV B.A., 1978: Engineering significance of texture in studying the mechanical properties of clay soils and making calculation. Proc. III Congr. Int A.I.G.I., 1, 363–377, Madrid.Google Scholar
  15. RAO S.M., SRIDHARAN A. and CHANDRAKARAN S., 1989: Influence of drying on the liquid limit behaviour of a marine clay. Géotechnique. v. 39, No. 4, pp. 715–719.CrossRefGoogle Scholar
  16. ROBERT M., VENEAU G. and HERVIO M., 1983: Influence des polications du fer et de l'aluminium sur les propriétés des argiles. Science du Sol. Bull. de A.F.E.S. No. –4, pp. 235–251.Google Scholar
  17. ROSENQVIST I.Th., 1955. Investigation in the clay-electrolyte-water system. Norw. Geotec. Inst., publ. No. 9, pp. 3–120.Google Scholar
  18. ROSENQVIST I.Th., 1959: Physico-chemical properties of soils: soil water systems. Amer. Soc. Civil Eng. Proc., v. 85, No. SM2, part 1, paper 2000, pp. 31–53.Google Scholar
  19. ROSENQVIST I.Th., 1960: The influence of Physico-chemical factors upon the mechanical properties of clays. Lecture at the Ninth National Conference on Clays and Clay Minerals, Lafayette, Indiana, pp. 5–8.Google Scholar
  20. SCHOFIELD R.K. and SAMSON H.R., 1954: Flocculation of kaolinite due to the attraction of oppositely charged crystal flakes. Faraday Soc. Discuss. v. 18, pp. 135–145.CrossRefGoogle Scholar
  21. SHEPARD P.F., 1954: Nomenclature based on sand, silt, clay rations. Journ. Sedim. Petr., v. 24.Google Scholar
  22. SHOOK J.F. and FANG H.Y., 1961: A study of operator variability in the determination of liquid limit and plastic limit of soils. Highw. Res. Board. Highw. Res. Abstract 31, No. 9, pp. 26–28.Google Scholar
  23. SRIDHARAN A., RAO S.M. and MURTHY N.S., 1988: Liquid limit of kaolinite soils. Géotechnique, v. 38, No. 2, pp. 191–198.CrossRefGoogle Scholar
  24. STEPKOWSKA E.T. and POZZUOLI A., 1990: Microstructure and Properties of Clays. Min. Petr. Acta XXXIII, pp. 101–116.Google Scholar
  25. TERZAGHI K., 1925: Erdbaumechanik auf bodenphysikalischer grundlage. Franz Denticke Press, Leipzigang and Vienna, 399 pp.Google Scholar
  26. VENIALE F., 1983: Consolidamento e stabilizzazione dei terreni argillosi mediante diffusione di sali (KCl). Ingegneria ferroviaria, No. 6, pp. 1–9.Google Scholar
  27. VENIALE F., 1985: The role of microfabric in clay soil stability. Miner. Petrogr. Acta, v. 29-A, pp. 101–119.Google Scholar
  28. VIDALIE J.-F., 1977: Relation entre les propriétés physico-chimiques et les caractéristiques mécaniques des sols compressibles. Rapport de recherche LCPC, Paris, No. 65, 87 pp.Google Scholar
  29. YONG R.N. and OHTSUBO M., 1986: Interparticle action and rheology of kaolinite-amorphous iron hydroxide (ferrihydrite) complexes. Submitted to Applied Clay Science. Internat. Journal.Google Scholar

Copyright information

© International Association of Engineering Geology 1994

Authors and Affiliations

  • U. Gori
    • 1
  1. 1.Institute of Applied GeologyUniversity of UrbinoItaly

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