This is a presentation made by Dr J D Bapat, during his talk on the "Durability of Concrete", on the Foundation Day of Indian Concrete Institute, Pune Centre, India. The presentation includes the role played by the mineral admixtures in imparting the strength and durability to concrete. It also mentions different mechanisms of the deterioration of concrete.

1. DURABILITY OF CONCRETE
by
Dr J D Bapat
http://www.drjdbapat.com
21 February 2019
Foundation Day
Indian Concrete Institute Pune Centre

2. ACKNOWLEDGEMENT
• WITH SINCERE THANKS TO THE PUBLISHER:
• I ACKNOWLEDGE THAT WHILE PREPARING THIS
PRESENTATION I HAVE USED INFORMATION GIVEN IN MY
BOOK:
“MINERAL ADMIXTURES IN CEMENT AND CONCRETE”
CRC PRESS – TAYLOR & FRANCIS GROUP

3. DURABILITY OF CONCRETE
DURABILITY IS SYNONYMOUS WITH APPLICATION OF
MINERAL ADMIXTURES IN CEMENT & CONCRETE
PULVERISED FUEL ASH (PFA)
 BLAST FURNACE SLAG (BFS)
 SILICA FUME (SF)
 RICE HUSK ASH (RHA)
 METAKAOLIN

4. DURABILITY OF CONCRETE
HOW MINERAL ADMIXTURES
IMPART STRENGTH & DURABILITY
TO CONCRETE

5. DURABILITY OF CONCRETE
ERREGULAR SHAPE CEMENT PARTICLES

6. DURABILITY OF CONCRETE
SPHERICAL FA PARTICLES

7. DURABILITY OF CONCRETE
PARTICLE SIZE OF RAW FA RANGES MOSTLY FROM 1
TO 100 MICRON
 UNDER 10 MICRON: CONTRIBUTE TO EARLY,
7 & 28 D, STRENGTH
 BETWEEN 10 & 45 MICRON: REACT SLOWLY &
CONTRIBUTE TOWARD LATE STRENGTH , UP TO 1
YEAR
ABOVE 45 MICRON: CONSIDERED INERT & LARGELY
ACT AS FINE SAND OR FILLER

8. DURABILITY OF CONCRETE
STRENGTH INCREASE CONTINUES OVER LONG TIME PERIOD

9. DURABILITY OF CONCRETE
SLAG GRADES
 ASTM C-989-09: SPECIFIES THREE GRADES OF GGBS
BY ACTIVITY INDEX: GRADE 80, 100 & 120
 GRADE 120: REPRESENTS HIGHEST STRENGTH

10. DURABILITY OF CONCRETE
ITZ
0% SF 10% SF

11. DURABILITY OF CONCRETE
CSH

12. DURABILITY OF CONCRETE

13. DURABILITY OF CONCRETE
GHATGHAR DAM IN ROLLER COMPACTED
CONCRETE WITH 60% FA

14. DURABILITY OF CONCRETE
CURING
CURING: IS A PROCESS OF PREVENTING LOSS OF
MOISTURE FROM CONCRETE, WHILE MAINTAINING
SATISFACTORY TEMPERATURE REGIME
 EARLY & LONG TERM CURING IS BENEFICIAL FOR
DEVELOPMENT OF CONCRETE PROPERTIES
 ADEQUATE & CONTINUOUS SUPPLY OF WATER IS
NECESSARY FOR LONG-TERM STRENGTH DEVELOPMENT &
IMPROVED DURABILITY PERFORMANCE OF CONCRETE WITH
MINERAL ADMIXTURES

15. DURABILITY OF CONCRETE
CONCRETE
DETERIORATION

16. DURABILITY OF CONCRETE
CARBONATION
CARBONATION: PRECIPITATION OF CALCITE (CaCO3)
CH + CO2 = CaCO3
 SIDE EFFECT – 1: CORROSION
 SIDE EFFECT – 2: STRENGTH REDUCTION
 ULTIMATE RESULT: LOSS OF STRENGTH, VOLUMETRIC
DECREASE (SHRINKAGE) & CRACKING & INCREASE IN
CONCRETE POROSITY

17. DURABILITY OF CONCRETE

18. DURABILITY OF CONCRETE
CARBONATION TESTING

19. DURABILITY OF CONCRETE
ALKALI-AGGREGATE REACTION (AAR)
 TERMED AS AAR WHEN AGGREGATES CONTAINING CERTAIN
DOLOMITIC (Ca + Mg) OR SILICEOUS MINERALS REACT WITH
SOLUBLE ALKALIES IN CONCRETE & SOMETIMES RESULT IN
DETRIMENTAL EXPANSION, CRACKING & PREMATURE LOSS OF
SERVICEABILITY OF CONCRETE STRUCTURES AFFECTED
 ALL KINDS OF CONCRETE STRUCTURES MAY BE AFFECTED (.)
STRUCTURES IN DIRECT CONTACT WITH WATER, SUCH AS DAMS &
BRIDGES, ARE PARTICULARLY SUSCEPTIBLE TO AAR.
 TWO TYPES OF AAR: (A) ALKALI–CARBONATE REACTION (ACR) &
(B) ALKALI–SILICA REACTION (ASR), DIFFERING IN TYPE OF
AGGREGATE MINERAL PHASES & REACTION MECHANISMS

20. DURABILITY OF CONCRETE
CONCRETE PAVEMENT CRACKED DUE TO ASR

21. DURABILITY OF CONCRETE
CORROSION OF REINFORCEMENT
 CORROSION OF REINFORCEMENT OCCURS WHEN
ALKALINITY (pH) OF SURROUNDING PORE SOLUTION
FALLS SUBSTANTIALLY DUE TO CHLORIDE PENETRATION
& STEEL IS EXPOSED
 EXPOSED STEEL GETS CORRODED IN PRESENCE OF
WATER & OXYGEN
 FORMATION OF EXPANSIVE CORROSION PRODUCTS
(RUST) THAT OCCUPY SEVERAL TIMES VOLUME OF
ORIGINAL STEEL
 EXPANSIVE CORROSION PRODUCTS CREATE TENSILE
STRESS IN CONCRETE SURROUNDING CORRODING
STEEL REBAR, LEADING TO CRACKING & SPALLING OF
CONCRETE COVER

22. DURABILITY OF CONCRETE
FLY ASH CONCRETE IS USED UNDER SEVERE EXPOSURE CONDITION
SUCH AS IN DECKS & PIERS OF SUNSHINE SKYWAY BRIDGE,
TAMPA BAY, FLORIDA

23. DURABILITY OF CONCRETE
SULPHATE ATTACK
OBSERVED WHEN STRUCTURES ARE EXPOSED TO
SULFATE SOLUTIONS OR BUILT IN SULFATE BEARING SOIL
OR GROUND WATER
 ALL COMMONLY OBTAINED WATER SOLUBLE SULPHATES
ARE DELETERIOUS (Mg > Na > Ca) BUT EFFECT IS SEVERE
WHEN IT IS ASSOCIATED WITH Mg, AS IT ATTACKS C-S-H
 SULFATES REACT WITH PORE SOLUTION TO PRECIPITATE
EXPANSIVE GYPSUM, ETTRINGITE OR THAUMASITE OR A
MIXTURE OF THESE COMPOUNDS, DEPENDING UPON
TEMPERATURE & OTHER FAVORABLE CONDITIONS
 PRECIPITATION LEADS TO STRESS WITHIN MATERIAL,
INDUCING EXPANSION, STRENGTH LOSS, SPALLING &
SEVERE DEGRADATION

24. DURABILITY OF CONCRETE
JOIN THE GROUP: MODERN CONCRETE
WHATSAPP ON: 9422517402
NAME:
ORGANISATION:
DESIGNATION:

25. THANKS !!
www.drjdbapat.com