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Recent Innovations in Concrete & Foundations Leading Growth

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Presentation on theme: "Recent Innovations in Concrete & Foundations Leading Growth"— Presentation transcript:

1 Recent Innovations in Concrete & Foundations Leading Growth
Sustainable By Dr. N V Nayak Principal Advisor, Gammon India Limited Chairman, Geocon International Pvt. Ltd Organizers : ISSE, Pune District Center The First Memorial Lecture In Memory of Late Prof. Y.S. Sane 9TH Sep 2014

2 Concrete 1.0 Preamble “Worldwide levels of carbon dioxide, have reached their highest level in 3 million years, US Scientists have said”. “Times of India, Mumbai, June 2013” “In 1.8bn years Earth Will Become Too Hot As Seas Will Evaporate” “Times of India, Mumbai, 20th September 2013”

3 We have to reverse this trend, for our survival for the future.
World Average Temperature will rise by at least 4°C by the year 2100 and at least by 8°C by 2200. “Times of India, Mumbai, 21st October 2013” “East Himalayan Forests Turning Brown” “Times of India, Mumbai, 2nd January 2014” We have to reverse this trend, for our survival for the future.

4 Without affecting the Growth/Development by
How? & Without affecting the Growth/Development by Sustainable Development; Why Discuss “Concrete” for Sustainable Development? Concrete is Most Widely used construction Material only next to water. It Generally produces Carbon Dioxide (CO2).

5 2.0 Sustainable Development
Annual World Concrete Consumption : Mt Annual India’s Concrete consumption : t Mt Target without increased cement : Mt production (4 Times) World Annual Cement Production :4000Mt Consumption (in 2013) China’s Annual Cement Production : Mt (58.7%) India’s Annual Cement Production : Mt (6.7%)

6 India 6.7% China 58.7 %

7 3.0 Emission of CO2 Concrete Production for Growth Must
1 t of Cement Production releases t of CO2 1 t of Cement consumed in (-) 0.4 t of CO2 concrete absorbs while hardening Therefore, net 1 t of cement produced and releases consumed in concrete t of CO2 emits Hence we in India release Mt of CO2 producing & Consuming 280 Mt of Cement Annually / day Concrete Production for Growth Must How to make it Sustainable

8 4.0 Sustainable Concrete Production
6 Steps to be followed (*)Make Compulsory use of Secondary Cementing Material (SCM) (Saving Roughly 60-70%) Produce more Durable Concrete (Increased Life Almost Double) (*) Use Higher Strength Concrete (Saving roughly 30%).

9 (*)Use Higher Size of Aggregate (MSA) in Concrete
(Saving roughly 10%). (*)Use optimum Cement Content in Concrete. Encourage use of “Carbon Negative Cement”. With (*) alone, we can produce ≈ 4 times the concrete for given amount of cement manufactured.

10 4.1 Main Secondary Cementing Materials
Fly Ash (FA) –Annual Production – 200 Mt; Ground Granulated Blast Furnace Slag (GGBS); - Annual Production : 90 Mt Metakaoline (MK); – Annual Production : 7000 t ( Complete Export……..) Rice Husk Ash (RHA); Micro-silica (MS); Ultrafine Fly Ash & Ultrafine GGBS (UFFA; UFS, Alcofine) (Recent Innovations) Annual Production : (5000 t t) = 20000t Annual Export : (2000 t t) = 6000 t… (30%)

11 4.2 Codal Provisions

12 Author’s Recommendation
Use fly Ash up to = 50% Use 70% in combination with Fly Ash + GGBS, or 85% GGBS Alone. Why ? Avoid Micro Silica (MS) ; Why ? (explained later) Substitute MS by UFS/Alccofine, Ultrafine Fly Ash Why ?

13 4.3 Durable Concrete Present Practice, Design = years Life AIM Design for Life = Years Possible Increased Life - Reduced Concrete Requirement - Reduced Cement Requirement

14 Solution Common to all Low w/b ratio ≈ 0.3
To make Durable Concrete, Concrete to Resist certain Aggressive Environment (Mainly 6) 1.0 Chloride corrosion 2.0 Carbonation corrosion 3.0 Alkali Silica Reaction 4.0 Sulphate attack 5.0 Industrial waste 6.0 Casual approach Why ? (See photos below) Solution Common to all Low w/b ratio ≈ 0.3

15 To make Durable Concrete, Concrete to Resist certain Aggressive Environment

16 4.3.1 Chloride Corrosion Solution SCM Maximum Permissible limit
GGBS in marine conditions preferred. Fly ash & not GGBS in Roads In General 70% replacement GGBS + fly ash together

17 4.3.2 Carbonation Corrosion
Solution Fly ash preferred If GGBS used, Restrict to 50%; for higher percentage plastering is to be adopted.

18 4.3.3 Damp patches on the surface of a reinforced concrete arch affected by ASR
Solution High permissible % of SCM like fly ash (25 to 50%) GGBS (50 to 70%) Metakaoline (10 to 20%) Silica Fume (5 to 10%)

19 4.3.4 Sulphate Attack Solution High percentage of GGBS – 1st preference Fly ash – 2nd preference Not to be preferred Silica Fume Metakaoline

20 4.3.5 Pile Concrete in Industrial Environment
Normally we determine pH, Chloride and Sulphate in ground Water and Subsoil; Many other factors of ground water affect performance of concrete; These are of importance in Industrialized Areas. Why? [See Figures]

21 Influence of Industrial Wastes on Structures

22 Solution: GGBS : > 50% (1st Preference) : < 50% (2nd Preference) Fly Ash : ≈ 50% (3rd Preference)

23 Summary of effectiveness of SCM on concrete
Type of SCM % Addition with respect to Total Cementitiou s content Resistance to Alkali-Silica Reaction/Exp ansion On Carbonation Resistance On Chloride Resistance On Sulphate Resistance On Industrial Waste Fly ash 10% to 25% 26% to 50% Good to Very Good Excellent Moderate Good Slightly better than OPC Better than 1(a) GGBS 50% 50 to 70% Very Good Poor Silica Fume 5 to 10% - Metakaoline 10 to 20%

24 Category Preferential order of Various SCM Alkali-Silica Reaction Fly ash (High%), GGBS (high%), Silica Fume, Metakaoline Carbonation Fly ash, GGBS (<50%), Silica Fume, Metakaoline GGBS (>50%) Chloride Corrosion Fly ash (>26%), GGBS (>50%) Silica Fume, Metakaoline Fly ash (≤25%), GGBS (≤50%) Sulphate Resistance Fly ash Industrial Waste GGBS (> 50%) GGBS (<50%) Fly ash (<50%)

25 Densely Reinforced Beam-Column Junction
4.3.6 CASUAL APPROACH Innumerable cases Densely Reinforced Beam-Column Junction

26 Solution Self Compacting Concrete

27 Benefits of Ultrafine Slag and Fly ash
Better Workability & Retention Period Better Pumpability Early Strength Gain Reduced Drying Shrinkage Better Sulphate Resistance Better Pore Size and Particle Packing (Reduced permeability) Better Resistance to Industrial Waste Reduced Cost

28 Recent & Future Developments of Concrete
Ultrafine Slag & Ultrafine Fly ash - Need Fast Implementation Self curing concrete High Priority Dry mixing of concrete in Batching plant High Priority Industry waste as aggregate Bendable concrete Self cleaning concrete Self healing concrete (Bacterial concrete) Carbon negative cement controlled permeability formwork

29 5.0 Foundations : Pile Foundations - Bored Cast-in-situ
Preamble Simple innovations are referred here which will have great effect on durability and sustainability

30 Taets Pile Breaker 5.1 Removal of Concrete above cutoff level
Chipping of concrete by Jack Hammer by Wedge Method – Widely adopted

31 5.1 Removal of Concrete above cutoff level
Performance of Taets Consequences Micro Cracks getting developed in Piles below cutoff level and chances of endangering its performance. Measures for Improved Performance ????? Taets Pile breaker – Costly but time effective and quality suspect

32 5.1Removal of Green Concrete above pile cut-off
Developed by Speaker and adopted in IRC 78 – 2011 Methodology Remove Concrete soon after completion of Pile Concrete; Generally removed manually by Tumbler for depth up to 0.5m below ground; Special Tool is used for deeper depth (See Figure ); After removal, Vibrate Concrete using Rammer (Fig in next slide); In absence of Ramming/Vibration, Air voids will be present in concrete which will result in strength reduction Scooping Tool

33 5.2 Removal of Green Concrete above pile cut-off
Rammer for Vibration of Concrete after scooping Compressive Strength Results

34 5.3 L Bend to Pile Reinforcement Cage
Theoretically Not Required Except in some special cases. Majority Still Provide Consequences ??????

35 L Bend to Pile Reinforcement Cage (Contd..)
Reasons: Proper flushing may not be possible; Concrete Flow also may not be proper. (see Adjacent pic) Recommendations : Avoid L Bend in Main Reinforcement steel at bottom of Pile, unless mandated Sand, Not Concrete

36 5.4 Socketing of Pile in Weathered/Soft Rock
Many Practices are adopted to decide Socket Length; Speaker has been Adopting “Cole-Stroud Approach Based on N Values of SPT” since 1974. (Now adopted by Bureau ofIndian Standards “IS ”) Main Point to note FS = 3 in Friction and also in End Bearing. Thorough Investigation needed Was adopted for Zuari- Mandovi bridges for KRCL, Goa India. (see Adjacent Figure).

37

38 Socketing of Pile in Weathered / Soft Rock (Contd..)
N Value of SPT PPR Value (tm/m2/cm) Remarks 50 37.35 For N Values in between, Linear Extrapolation will be adopted 100 74.70 150 112.05 200 149.40 250 186.75 This approach can be adopted up to N Value of 400 300 224.10 350 261.45 400 298.80 Some Insist of doing “SPT” Test. This is not desirable from time and cost consideration. To overcome this problem, quality control concept involving “Pile Penetration Ratio-PPR” has been developed. PPR Reflects Energy in tm required to Advance Borehole of 1m2 cross section by 1 cm

39 5.5 .Torque Meters on Control Panel
Force Meter

40 5.6 Convert Marine Piling to Land Piling
In Konkan Railway Project, out of 15 marine jobs, 13 jobs were converted fully to land piling by AFCONS 4.5 Km long Bridge on Godavari River converted into Land Piling by Gammon, Max Depth of water ~ 14m (See Adjacent pic) Advantages : Substantial Time and Cost Reduction

41 5.7 Settlement Criteria for Load Test

42 Settlement Criteria For Load Test Cont’d…
Curve (a) – IS 2911 Part 4 – 1.5 times design load Curve (b) - IS 2911 Part 4 – 1.5 times design load Curve (c ) - 10% of Pile ultimate load Curve (d) – 2% of pile 1.5 times design load Curve (e ) - 3% of pile dia @ 1.5 times design load

43 5.8 Capacity of Under ream Piles
IS 2911 – Part 3 – 1980 – Incorrect Recommendation. Why?

44

45 5.9 MSA in Foundations & Substructures
Recommend – 40mm MSA Save 10% in cementitious material

46 5.10 Highly Innovative Indian Design
Zuari Bridge on Konkan Railway Novel Concept Adopted for the First Time in India Only 14 Well Foundations on entire Konkan Railway Project (over 100 bridges) Caissons / Wells were pneumatically sunk. Founding depth of one caisson was 30 m below water level. - Workers could hardly work for ½ hour. Hence Novel Idea founding caisson on piles was adopted for the first time in India (See Pic in Next Slide)

47 Details of Caisson Resting on Piles

48 Way Forward Determined Approach by all of us to follow “Sustainable Growth Guidelines” Saving in Piling – Minimum 25% over the present practice Saving in Concrete – Minimum 10% over the present practice

49 Thank you “Jai Hind” “Jai Bharat (India)” “Jai Maharashtra”


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