Presentation on theme: "Recent Innovations in Concrete & Foundations Leading Growth"— Presentation transcript:
1Recent Innovations in Concrete & Foundations Leading Growth SustainableByDr. N V NayakPrincipal Advisor, Gammon India LimitedChairman, Geocon International Pvt. LtdOrganizers : ISSE, Pune District CenterThe First Memorial LectureIn Memory of Late Prof. Y.S. Sane9TH Sep 2014
2Concrete1.0 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”
3We 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.
4Without affecting the Growth/Development by How?&Without affecting the Growth/Development bySustainable Development;Why Discuss “Concrete” for Sustainable Development?Concrete is Most Widely used construction Material only next to water.It Generally produces Carbon Dioxide (CO2).
52.0 Sustainable Development Annual World Concrete Consumption : MtAnnual India’s Concrete consumption : t MtTarget without increased cement : Mtproduction (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%)
73.0 Emission of CO2 Concrete Production for Growth Must 1 t of Cement Production releases t of CO21 t of Cement consumed in (-) 0.4 t of CO2concrete absorbs while hardeningTherefore, net 1 t of cement producedand releases consumed in concrete t of CO2emitsHence we in India release Mt of CO2producing & Consuming 280 Mt of Cement Annually / dayConcrete Production for Growth MustHow to make it Sustainable
84.0 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.
104.1 Main Secondary Cementing Materials Fly Ash (FA)–Annual Production – 200 Mt;Ground Granulated Blast Furnace Slag (GGBS);- Annual Production : 90 MtMetakaoline (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) = 20000tAnnual Export : (2000 t t) = 6000 t… (30%)
12Author’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 ?
134.3 Durable ConcretePresent Practice, Design = years Life AIM Design for Life = Years Possible Increased Life - Reduced Concrete Requirement - Reduced Cement Requirement
14Solution 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)SolutionCommon to all Loww/b ratio ≈ 0.3
15To make Durable Concrete, Concrete to Resist certain Aggressive Environment
164.3.1 Chloride Corrosion Solution SCM Maximum Permissible limit GGBS in marine conditions preferred.Fly ash & not GGBS in RoadsIn General 70% replacement GGBS + fly ash together
174.3.2 Carbonation Corrosion SolutionFly ash preferredIf GGBS used, Restrict to 50%; for higher percentage plastering is to be adopted.
184.3.3 Damp patches on the surface of a reinforced concrete arch affected by ASR SolutionHigh permissible % of SCM likefly ash (25 to 50%)GGBS (50 to 70%)Metakaoline (10 to 20%)Silica Fume (5 to 10%)
194.3.4 Sulphate AttackSolutionHigh percentage ofGGBS – 1st preferenceFly ash – 2nd preferenceNot to be preferredSilica FumeMetakaoline
204.3.5 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]
23Summary of effectiveness of SCM on concrete Type of SCM% Addition with respect toTotal Cementitiou s contentResistance to Alkali-Silica Reaction/Exp ansionOn Carbonation ResistanceOn Chloride ResistanceOn Sulphate ResistanceOn Industrial WasteFly ash10% to 25%26% to 50%Good to Very GoodExcellentModerateGoodSlightly better than OPCBetter than 1(a)GGBS50%50 to 70%Very GoodPoorSilica Fume5 to 10%-Metakaoline10 to 20%
27Benefits of Ultrafine Slag and Fly ash Better Workability & Retention PeriodBetter PumpabilityEarly Strength GainReduced Drying ShrinkageBetter Sulphate ResistanceBetter Pore Size and Particle Packing (Reduced permeability)Better Resistance to Industrial WasteReduced Cost
28Recent & Future Developments of Concrete Ultrafine Slag & Ultrafine Fly ash - Need Fast ImplementationSelf curing concrete High PriorityDry mixing of concrete inBatching plant High PriorityIndustry waste as aggregateBendable concreteSelf cleaning concreteSelf healing concrete (Bacterial concrete)Carbon negative cementcontrolled permeability formwork
295.0 Foundations : Pile Foundations - Bored Cast-in-situ Preamble Simple innovations are referred here which will have great effect on durability and sustainability
30Taets Pile Breaker 5.1 Removal of Concrete above cutoff level Chipping of concrete by Jack Hammer by Wedge Method – Widely adopted
315.1 Removal of Concrete above cutoff level Performance of TaetsConsequencesMicro 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
325.1Removal of Green Concrete above pile cut-off Developed by Speaker and adopted in IRC 78 – 2011MethodologyRemove 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 reductionScooping Tool
335.2 Removal of Green Concrete above pile cut-off Rammer for Vibration of Concrete after scoopingCompressive Strength Results
345.3 L Bend to Pile Reinforcement Cage Theoretically Not Required Except in some special cases.Majority Still ProvideConsequences ??????
35L 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 mandatedSand, Not Concrete
365.4 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 noteFS = 3 in Friction and also in End Bearing.Thorough Investigation neededWas adopted for Zuari- Mandovi bridges for KRCL, Goa India.(see Adjacent Figure).
38Socketing of Pile in Weathered / Soft Rock (Contd..) N Value of SPTPPR Value(tm/m2/cm)Remarks5037.35For N Values in between, Linear Extrapolation will be adopted10074.70150112.05200149.40250186.75This approach can be adopted up to N Value of 400300224.10350261.45400298.80Some 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
405.6 Convert Marine Piling to Land Piling In Konkan Railway Project, out of 15 marine jobs, 13 jobs were converted fully to land piling by AFCONS4.5 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
42Settlement Criteria For Load Test Cont’d… Curve (a) – IS 2911 Part 4 – 1.5 times design loadCurve (b) - IS 2911 Part 4 – 1.5 times design loadCurve (c ) - 10% of Pile ultimate loadCurve (d) – 2% of pile 1.5 times design loadCurve (e ) - 3% of pile dia @ 1.5 times design load
435.8 Capacity of Under ream Piles IS 2911 – Part 3 – 1980 –Incorrect Recommendation.Why?
455.9 MSA in Foundations & Substructures Recommend – 40mm MSASave 10% in cementitious material
465.10 Highly Innovative Indian Design Zuari Bridge on Konkan RailwayNovel Concept Adopted for the First Time in IndiaOnly 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)