Knowledge FOr Resilient soCiEty KURS CJELOIVOTNOG UENJA - - PowerPoint PPT Presentation

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Knowledge FOr Resilient soCiEty KURS CJELOIVOTNOG UENJA - - PowerPoint PPT Presentation

Mar 23, 2023 18 likes •408 views

Banja Luka 10.03.2020 Knowledge FOr Resilient soCiEty KURS CJELOIVOTNOG UENJA PROTIVPOARNE GRAEVINSKE MJERE SPOLJNI UTICAJ SULFATA NA BETON Doc. Dr Vesna Bulatovi The European Commission support for the production of this publication

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Banja Luka 10.03.2020

KURS CJELOŽIVOTNOG UČENJA PROTIVPOŽARNE GRAĐEVINSKE MJERE SPOLJNI UTICAJ SULFATA NA BETON

  • Doc. Dr Vesna Bulatović

Knowledge FOr Resilient soCiEty

The European Commission support for the production of this publication does not constitute an endorsement of the contents which reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein.

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Concrete durability Microclimate Concrete quality Transport mechanisms Water and aggressive Temprature and pressure Diffusion Capillary suction Permeability Cement type w/b Curing Pore connectivity binding Porosity Degree of hydration

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Initiation Propagation Accept limit Technical Service Life Damage

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Initiation Propagation Accept limit Technical Service Life Damage

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Initiation Propagation Accept limit Technical Service Life Damage

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DETERIORATION OF CONCRETE Mechanical Chemical Physical · Impact · Overload · Movement (e.g.settlement) · Explosion · Vibration · Alkali-aggregate reaction · Aggressive agents e.g.sulfates,soft water,salts · Biological activities · Freeze/thaw · Thermal · Salt crystallization · Erosion · Wear

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  •  alkali-silica reaction (ASR)

 alkali-carbonate reaction (ACR)

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The microstructure of the concrete is changed under this attack. These changes may vary in the type of severity, but they commonly include chemical sulfate attack and physical attack. Common damages:

  • Cracking,
  • Expansion
  • Loss of bond between the cement paste and aggregate.

The expansion resulting from sulfate attack is generally attributed to the formation of gypsum and ettringite.

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Sulfate attack is categorize into:

  • Chemical
  • Physical
  • Internal
  • External
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Liquid Reaction zone Pore solution Original cement paste

Na+ OH- SO42- Na+ OH- Ca2+ SO42- CaSO4·2H2O 6CaO·Al2O3·3SO3·32H2O (ettringite) Al(OH)-4 Ca(OH)2 4CaO·Al2O3·SO3·12H2O (monosulfate)

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Liquid Reaction zone Pore solution Original cement paste

Mg2+ SO42- Mg(OH)2 SiO2·aq 3MgO·2SiO2·2H2O CaSO4·2H2O OH- Mg2+ Ca2+ SO42- Ca(OH)2 C-S-H AFm AFt

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Class of chemical attack Max w/c Min strength class Min cement content (kg/m3) Other requirements XA1 0.55 C30/37 300 XA2 0.50 C30/37 320 Sulfate-resisting cement XA3 0.45 C35/45 360

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Knowledge FOr Resilient soCiEty