Role of carbonate on the swelling/shrinkage of clayey soils

In the past decades, the succession of several periods of drought caused damages on individual constructions in France. After the summer heat in 2003, an increasing number of pathologies with cracks appeared consequently to soil deformation under foundations because of the presence of sensitive clay. Indeed, smectites may swell and shrink when the soil water content varies. So characterize the swelling/shrinkage potential of soils after identifying the presence of clay represents a real challenge to reduce expensive reparations on damaged constructions and prevent new buildings to sinister. Experiments were conducted on the two major clayey materials as named Romainville?s green clay and Argenteuil?s blue marl and at the origin of the pathologies encountered near to Paris. After the geotechnical, physico-chemical and mineralogical characterization of materials extracted from a gypsum carrier, mechanical tests were applied to better understand the relation between microstructural characteristics of soils and macroscopic behaviour. An automatised instrumented apparatus developed in LCPC to measure the volumetric shrinkage were uses as well as the free swell test (Makki, 2008). Several parameters impacting to the soil behaviour were identified as the soil density, the numbers of humidification/desiccation cycles, the sample structure (intact or compacted after destructurated soil sample) and the presence of carbonates. This last parameter appears as determining as it can modify the soil sensitivity, compared to the same soils with similar clay. Between aggregates, the carbonates may form cementation submitted to alteration under dry/wet cycles. This cementation, we tried to put in evidence from observations by scanning electron and optical microscopies completed by porosimetric measurement by mercury intrusion, reduce the soil deformation. So, such parameters must be considered in the classification of soil sensitivity to swelling-shrinkage.

  • Authors:
    • DUC, Myriam
    • MAKKI, Lamis
    • MAGNAN, Jean Pierre
    • MALOULA, Aurélie
  • Conference:
  • Publication Date: 2009

Language

  • English

Media Info

  • Media Type: Digital/other
  • Pagination: 31p

Subject/Index Terms

Filing Info

  • Accession Number: 01497696
  • Record Type: Publication
  • Source Agency: Institut Francais des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)
  • Files: ITRD
  • Created Date: Nov 7 2013 11:49AM