Presentation on theme: "Recent Innovations in Concrete & Foundations Leading Growth By Dr. N V Nayak Principal Advisor, Gammon India Limited Chairman, Geocon International Pvt."— Presentation transcript:
Recent Innovations in Concrete & Foundations Leading Growth By Dr. N V Nayak Principal Advisor, Gammon India Limited Chairman, Geocon International Pvt. Ltd Organizers : ISSE, Pune District Center Sustainable The First Memorial Lecture In Memory of Late Prof. Y.S. Sane 9 TH Sep 2014
I.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, 20 th September 2013”
World Average Temperature will rise by at least 4°C by the year 2100 and at least by 8°C by “Times of India, Mumbai, 21 st October 2013” “East Himalayan Forests Turning Brown” “Times of India, Mumbai, 2 nd January 2014” We have to reverse this trend, for our survival for the future.
How? & Without affecting the Growth/Development by Sustainable Development; Why Discuss “Concrete” for Sustainable Development? o Concrete is Most Widely used construction Material only next to water. o It Generally produces Carbon Dioxide (CO 2 ).
2.0Sustainable Development Annual World Concrete Consumption: Mt Annual India’s Concrete consumption : 1000t Mt Target without increased cement : 4000 Mt production (4 Times) World Annual Cement Production :4000Mt Consumption (in 2013) China’s Annual Cement Production : 2350 Mt (58.7%) India’s Annual Cement Production: 280 Mt (6.7%)
India 6.7% China 58.7 %
3.0Emission of CO 2 1 t of Cement Production releases 0.9 t of CO 2 1 t of Cement consumed in (-) 0.4 t of CO 2 concrete absorbs while hardening Therefore, net 1 t of cement produced and releases consumed in concrete 0.5 t of CO 2 emits Hence we in India release 0.34 Mt of CO 2 producing & Consuming 280 Mt of Cement Annually / day Concrete Production for Growth Must How to make it Sustainable
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%).
(*)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.
4.1 Main Secondary Cementing Materials o Fly Ash (FA) –Annual Production – 200 Mt; o Ground Granulated Blast Furnace Slag (GGBS); - Annual Production : 90 Mt o Metakaoline (MK); – Annual Production : 7000 t ( Complete Export……..) o Rice Husk Ash (RHA); o Micro-silica (MS); o Ultrafine Fly Ash & Ultrafine GGBS (UFFA; UFS, Alcofine) (Recent Innovations) o Annual Production : (5000 t t) = 20000t o Annual Export : (2000 t t) = 6000 t… (30%)
4.2 Codal Provisions
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 ?
4.3Durable Concrete Present Practice, Design = years Life AIM Design for Life = Years Possible Increased Life -Reduced Concrete Requirement - Reduced Cement Requirement
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
To make Durable Concrete, Concrete to Resist certain Aggressive Environment
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
Solution Fly ash preferred If GGBS used, Restrict to 50%; for higher percentage plastering is to be adopted Carbonation Corrosion
Solution High permissible % of SCM like fly ash (25 to 50%) GGBS (50 to 70%) Metakaoline (10 to 20%) Silica Fume (5 to 10%) Damp patches on the surface of a reinforced concrete arch affected by ASR
4.3.4 Sulphate Attack Solution High percentage of GGBS – 1 st preference Fly ash – 2 nd preference Not to be preferred Silica Fume Metakaoline
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]
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 Moderate Good Excellent Good Good a)Slightly better than OPC b)Better than 1(a) GGBS 50% 50 to 70% Very Good Excellent Moderate Poor Very Good Excellent Very Good Excellent Very Good Excellent Silica Fume5 to 10%ExcellentModerateVery GoodModerate - Metakaoline10 to 20%ExcellentModerateVery GoodModerate -
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
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
5.0 Foundations : Pile Foundations - Bored Cast-in-situ Preamble Simple innovations are referred here which will have great effect on durability and sustainability
Taets Pile Breaker 5.1 Removal of Concrete above cutoff level Chipping of concrete by Jack Hammer by Wedge Method – Widely adopted
5.1 Removal of Concrete above cutoff level Performance of Taets Taets Pile breaker – Costly but time effective and quality suspect Consequences Micro Cracks getting developed in Piles below cutoff level and chances of endangering its performance. Measures for Improved Performance ?????
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
5.2Removal of Green Concrete above pile cut-off Rammer for Vibration of Concrete after scooping Compressive Strength Results
5.3 L Bend to Pile Reinforcement Cage Theoretically Not Required Except in some special cases. Majority Still Provide Consequences ??????
L Bend to Pile Reinforcement Cage (Contd..) Reasons: O Proper flushing may not be possible; O 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
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 (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).
Socketing of Pile in Weathered / Soft Rock (Contd..) O Some Insist of doing “SPT” Test. This is not desirable from time and cost consideration. O To overcome this problem, quality control concept involving “Pile Penetration Ratio- PPR” has been developed. O PPR Reflects Energy in tm required to Advance Borehole of 1m 2 cross section by 1 cm N Value of SPT PPR Value (tm/m 2 /cm) Remarks For N Values in between, Linear Extrapolation will be adopted This approach can be adopted up to N Value of
5.5.Torque Meters on Control Panel Torque Meters Force Meter
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
5.7 Settlement Criteria for Load Test
Settlement Criteria For Load Test Cont’d… a) Curve (a) – IS 2911 Part 4 – 1.5 times design load b) Curve (b) - IS 2911 Part 4 – 1.5 times design load c) Curve (c ) - 10% of Pile ultimate load d) Curve (d) – 2% of pile 1.5 times design load e) Curve (e ) - 3% of pile 1.5 times design load
5.8Capacity of Under ream Piles IS 2911 – Part 3 – 1980 – Incorrect Recommendation. Why?
5.9MSA in Foundations & Substructures Recommend – 40mm MSA Save 10% in cementitious material
5.10 Highly Innovative Indian Design Zuari Bridge on Konkan Railway Novel Concept Adopted for the First Time in India o Only 14 Well Foundations on entire Konkan Railway Project (over 100 bridges) o Caissons / Wells were pneumatically sunk. o 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)
Details of Caisson Resting on Piles
Way Forward “Sustainable Growth Guidelines” 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
Thank you “Jai Hind” “Jai Bharat (India)” “Jai Maharashtra”