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PRESENTATION TO 34 TH ANNUAL AIRPORTS CONFERENCE 3/02/11 By: Casimir J. Bognacki, PE, FACI Chief of Materials Engineering.

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Presentation on theme: "PRESENTATION TO 34 TH ANNUAL AIRPORTS CONFERENCE 3/02/11 By: Casimir J. Bognacki, PE, FACI Chief of Materials Engineering."— Presentation transcript:

1 PRESENTATION TO 34 TH ANNUAL AIRPORTS CONFERENCE 3/02/11 By: Casimir J. Bognacki, PE, FACI Chief of Materials Engineering

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4 JFK – BAY RUNWAY – 13R – 31L LENGTH: 14,600 WIDTH: 200 FEET CONCRETE DEPTH: 18 INCHES APPROXIMATELY:250,000 CUBIC YARDS OF CONCRETE 400,000 TONS OF ASPHALT

5 BAY RUNWAY – 13R – 31L ENTIRE RUNWAY WAS CLOSED FOR 120 DAYS. AFTER THIS TIME, 10,700 FEET OF THE RUNWAY WOULD BE COMPLETED. APPROXIMATELY 200,000 CUBIC YARDS OF CONCRETE WOULD BE PLACED IN THREE MONTHS.

6 BAY RUNWAY – 13R – 31L DESIGN LIFE OF ASPAHLT PAVEMENT YEARS. DESIGN LIFE OF PORTLAND CEMENT CONCRETE PAVEMENT IS 40 YEARS. INITIAL CONSTRUCTION COSTS FOR ASPHALT PAVEMENT IS 28% LESS THAN CONCRETE PAVEMENT. FOR A 40-YEAR LIFE CYCLE COST ANALYSES, THE CONCRETE PAVEMENT WAS 17% LESS.

7 END-RESULT SPECIFICATION IF THE FLEXURAL STRENGTH CRITERIA IS NOT MET, CONTRACTOR INCURS PAYMENT REDUCTIONS. IN ORDER TO QUALIFY FOR A BONUS OF 6%, THE PWL FOR FLEXURAL STRENGTH MUST BE 100 % AND MUST MEET THE CRITERIA FOR WATER CONTENT, AIR, AND RAPID CHLORIDE PERMEABILITY.

8 DURABLE & GREEN PORTLAND CEMENT CONCRETE PAVEMENTS LOW WATER CONTENT W/C <.45 LOW CEMENT CONTENT< 350 LBS. LOW TOTAL CEMENTITIOUS CONTENT < 550 LBS. SUBSTITUTE SUPPLEMENTARY CEMENTITIOUS MATERIAL FOR CEMENT40% TOTAL AGGREGATE CONTENT > 70% BY VOLUME USE LARGE NOMINAL MAXIMUM AGGREGATE 2 INCHES OR GREATER COMBINED AGGREGATE GRADATION COARSENESS FACTOR 70 WORKABILITY FACTOR 32 ENTRAIN AIR 5% + 1.5%

9 ACCEPTANCE CRITERIA FOR DELIVERED CONCRETE CONCRETE WAS EVALUATED STATISTICALLY ON A LOT BASIS Criteria *(PWL %) Flexural Strength > Days 95 * Water to Cement Ratio < Air Content 5% + 1.5% 70 ***Rapid Chloride Permeability Test < * Water Content is determined in the Field by Test Method AASHTO T-318. ***ASTM C-1202Accelerated Test – 7 73F o & F o. * PWL = PERCENT WITHIN LIMIT

10 ENHANCE QUALITY ACCEPTANCE TESTING FOR INCREASED DURABILITY DETERMINE WATER CONTENT IN DELIVERED CONCRETE – AASHTO T-318 – MICROWAVE TEST. SPECIFY LOW PERMEABILITY CONCRETE WITH THE USE OF SUPPLEMENTARY CEMENTITIOUS MATERIAL AND VERIFY WITH THE RAPID CHLORIDE PERMEABILITY TEST ASTM (ACCELERATED TEST SPECIMENS CURED FOR 7 73 o F AND 21 o F). AIR CONTENT ASTM C-231.

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12 AASHTO T-318 MICROWAVE OVEN TEST CONCRETE WATER CONTENT OUR EXPERIENCE 2% in-test coefficient of variation for ten specimens from same laboratory batch. 98% recovery of water batched in laboratory mixes. Absorbed water in aggregates used in NYC is not removed with microwave heating for 20 minutes. Testing a representative sample of the mix is very important.

13 MICROWAVE TEST AASHTO T-318 FIELD TEST RESULTS VARIABILITY WITHIN LOAD EWR LOT C - GARAGE Time10:3010:4010:5011:00In-Test Coefficient of Variation W/C Slump (inch) Air % Unit Weight (PCF)

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36 MIX DESIGN CEMENT TYPE IS ***550 LBS. FINE AGGREGATE1190 LBS. COARSE AGGREGATE2280 LBS. WATER220 LBS. AEA2 OZ. HRWR30 OZ. W/C.4 *** IS CEMENT A BLEND OF 58% CEMENT AND 42% GGBFS.

37 CONCRETE INDUSTRY - MYTHS ASTM C-78 IS MORE VARIABLE THAN ASTM C-39. AASHTO T-318 MICORWAVE TEST DOES NOT ACCURATELY DETERMINE WATER CONTENT IN CONCRETE. ASTM C-1202 – RAPID CHLORIDE PERMEABILITY TEST RESULTS TOO VARIABLE TO BE USED FOR ACCEPTANCE TESTING.

38 FIELD TEST RESULTS AVERAGE STD. DEVIATION COMPRESSIVE STRENGTH – 28 DAYS (PSI) (11.6***) FLEXURAL STRENGTH - 28 DAYS (PSI) (8.5***) W/C SLUMP (INCH)1.9 UNIT WEIGHT (PCF) AIR CONTENT (%)5 1 COULOMBS (***) = Coefficient of Variation

39 NOTE THE COEFFICIENT OF VARIABILITY FOR COMPRESSIVE STRENGTH, 11.6, WAS HIGHER THAN FOR FLEXURAL STRENGTH, 8.5. THE PORT AUTHORITY EXPERIENCE IS THAT THE FLEXURAL STRENGTH RESULTS EXHIBITS THE SAME OR LOWER VARIABILITY THAN COMPRESSIVE STRENGTH ON ALL PAVING PROJECTS.

40 RESULTS CONTRACTOR RECEIVED NO PAYMENT REDUCTIONS. BONUS PAYMENTS WERE MADE FOR 83% OF THE TEST LOTS FOR A TOTAL OF $1,149,733.

41 IN ORDER TO CONSTRUCT GREEN, DURABLE PORTLAND CEMENT CONCRETE PAVEMENTS, SUPPLEMENTARY CEMENTITIOUS MATERIALS MUST BE SUBSTITUTED FOR PORTLAND CEMENT. *** MOST COMMON SUPPLEMENTARY CEMENTITIOUS MATERIALS AVAILABLE IN THE NORTHEAST ARE FLY ASH (PRIMARILY TYPE F AND SOME TYPE C) AND GROUND GRANULATED BLAST FURNACE SLAG (GGBFS).

42 IN ORDER TO HAVE GREEN DURABLE CONCRETE PAVEMENTS WITH AN EXTENDED SERVICE LIFE, MORE EMPHASES MUST BE PLACED ON DURABILITY BY: REDUCING TOTAL WATER IN MIX. INCREASING AGGRGATE VOLUME. DECREASING PERMEABILTY.

43 THE IS CEMENT OF 550 LBS./CU YDS. CONSISTED OF CEMENT – 320 LBS. GGBFS -230 LBS. ASSUMING STRENGTH GAIN IS PROPORTIONAL TO QUANTITY OF CEMENTITIOUS MATERIAL. 550 LBS. OF IS CEMENT PRODUCED A FLEXURAL STRENGTH OF 1,095 PSI; THEREFORE, THE IS CEMENT CONTENT COULD HAVE BEEN REDUCED BY AT LEAST 20%. 550 LBS. OF CEMENTITIOUS MATERIAL WAS USED TO MAINTAIN WORKABILITY.

44 ASSUME A 20% REDUCTION IN IS CEMENT WAS REPLACED WITH FLY ASH OR GROUND LIMESTONE TO MAINTAIN WORKABILITY CEMENT260 LBS. GGBFS190 LBS. FLY ASH OR GROUND LIMESTONE100 LBS.

45 GREEN DURABLE PORTLAND CEMENT CONCRETE WITH 260 LBS. OF CEMENT OR LESS PER CUBIC YARD OF CONCRETE.

46 THE PREFERRED SUPPLEMENTARY CEMENTITIOUS MATERIALS FOR ENHANCING DURABILITY ARE FLY ASH-TYPE F AND GGFBS. THE PORT AUTHORITY OF NY & NJ’S EXPERIENCE IS THAT GGBFS PRODUCES MUCH HIGHER FLEXURAL STRENGTH THAN FLY ASH.

47 CEMENT (LBS.) GGBFS (LBS.)150 FLYASH (LBS.)150 FINE AGGREGATE (LBS.) COARSE AGGREGATES (LBS.) W/CM AIR % CONPRESSIVE 28 DAYS (PSI) FLEXURAL 28 DAYS (PSI) FLEXURAL 56 DAYS (PSI)625

48 CONTRACTION JOINT SPACING FAA STANDARD – 20 FT. X 20 FT. THE PORT AUTHORITY OF NY & NJ STANDARD 25 FT. X 25 FT. AND ANY SECTIONS WITH CRACKS PRIOR TO LOADING ARE TO BE REMOVED AT CONTRACTOR’S COST. BY INCREASING JOINT SPACING TO 25 FT., WE REDUCED THE JOINTS AND DOWELS BY 20%

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