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Aggregate and concrete microfracture

  • Hubbard F. H. 
  • Dhir R. K. 
Article

Abstract

Thin sections cut from cast concrete cylinders have been examined in transmitted light to investigate the significance of coarse aggregate type in “primary” microfracturing. Concretes manufactured with crushed-rock aggregates and gravel aggregates were studied and, in every case, the dominant fracture type was a parting of the aggregate-matrix bond Bond cracking was least severe with the marble aggregate where epitaxial calcita over-growth was indicated. The ability of bond cracks to maintain continuity by bridging surface irregularities, via mortar cracks, reduced the inhibiting influence of rough-surfaced aggregate on bond-crack development.

Keywords

Coarse Aggregate Matrix Crack Aggregate Concrete Plain Concrete American Concrete Institute 

Granulats et microfissuration des betons

Résumé

Des lames minces réalisées sur des cylindres de béton coulé ont été examinées en lumière transmise pour étudier l'importance des granulats grossiers dans la microfissuration “primaire”. Nous avons observé des bétons fabriqués avec des granulats issus de roches massives concassées et des granulats alluvionnaires et, dans tous les cas, le type de fissuration prédominant se présentait sous la forme d'un éclatement de la liaison granulat—matrice. Les fissures étaient moins développées dans le cas de granulats de marbre, à cause de la présence de liaisons épitaxiques. La faculté des fissures de se prolonger en franchissant les inégalités de surface, par l'intermédiaire des fentes dans le mortier, a réduit l'influence modératrice des granulats à surface rugueuse sur le développement des fissures.

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References

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Copyright information

© International Association of Engineering Geology 1980

Authors and Affiliations

  • Hubbard F. H. 
    • 1
  • Dhir R. K. 
    • 1
  1. 1.The UniversityDundeeScotland

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