Temperature Measurements in the Production of Quality Concrete

Transcription

1 Temperature Measurements in the Production of Quality Concrete John McClafferty PE (AZ) GCC - (915) January 13 & 14, 2017 NMSU Samuel P. Maggard Quality Concrete School 10/25/2016 1

2 1) Relevant chemistry of concrete (1/26) Calcium Ca C Silica Si S Aluminum, Al, A Iron Fe F 10/25/2016 2

3 1) Relevant chemistry of concrete (2/26) Major Oxides, stable rusted form Calcium Oxide (lime) CaO C Silica Oxide SiO2 S Aluminum Oxide Al2O3 A Iron (the grey) Fe2O3 F 10/25/2016 3

4 1) Relevant chemistry of concrete (3/26) Major Oxides, stable rusted form Calcium Oxide (lime) CaO C Silica Oxide SiO2 S Aluminum Oxide Al2O3 A Iron (the grey) Fe2O3 F Minor Oxides, catalysts Magnesium Oxide MgO M Sulfur Trioxide SO3 S Sodium Oxide Na2O NaEq = 0.65K20 + Na2O Potassium Oxide K2O Alkali Equivalent 10/25/2016 4

5 1) Relevant chemistry of concrete (4/26) Clinker Chemistry; Ca 3 SiO 5 or 3CaO. SiO 2 = C 3 S C 3 S, Tricalcium silicate, Alite, 50-65%, early psi Early Strength 1-2-3; 1st Round Knock Out 10/25/2016 5

6 1) Relevant chemistry of concrete (5/26) Clinker Chemistry; Ca 3 SiO 5 or 3CaO. SiO 2 = C 3 S C 3 S, Tricalcium silicate, Alite, 50-65%, early psi Ca 2 SiO 4 or 2CaO. SiO 2 = C 2 S C 2 S, Dicalcium silicate, Belite, 5-25%, later psi Longer Strength Gain. 10/25/2016 6

7 1) Relevant chemistry of concrete (6/26) Clinker Chemistry; Ca 3 SiO 5 or 3CaO. SiO 2 = C 3 S C 3 S, Tricalcium silicate, Alite, 50-65%, early psi Ca 2 SiO 4 or 2CaO. SiO 2 = C 2 S C 2 S, Dicalcium silicate, Belite, 5-25%, later psi Ca 3 Al 2 O 6 or 3CaO. Al 2 O 3 = C 3 A C 3 A, Tricalcium aluminate, Aluminate, 7-10% 10/25/2016 7

8 1) Relevant chemistry of concrete (7/26) Clinker Chemistry; Ca 3 SiO 5 or 3CaO. SiO 2 = C 3 S C 3 S, Tricalcium silicate, Alite, 50-65%, early psi Ca 2 SiO 4 or 2CaO. SiO 2 = C 2 S C 2 S, Dicalcium silicate, Belite, 5-25%, later psi Ca 3 Al 2 O 6 or 3CaO. Al 2 O 3 = C 3 A C 3 A, Tricalcium aluminate, Aluminate, 7-10% Ca 4 Al 2 Fe 2 O 10 or 4CaO. Al 2 O 3. Fe 2 O 3 = C 4 AF C 4 AF, Tetracalcium aluminoferrite, Ferite, 8-10% 10/25/2016 8

9 1) Relevant chemistry of concrete (8/26) 10/25/2016 9

10 1) Relevant chemistry of concrete (10/26) Cement Chemistry Clinker a mixture of various amounts of compounds. 10/25/

11 1) Relevant chemistry of concrete (9/26) Gypsum Chemistry Gypsum Plaster of Paris CaSO 4-2H 2 O CaSO 4-0.5H 2 O Anhydrite CaSO 4 95% Clinker + 5% Gypsum and finely ground = Cement 10/25/

12 1) Relevant chemistry of concrete (11/26) Hydration; cement & water reaction. C-S-H gel C3S, C2S & H2O is Tobermorite Gel. 10/25/

13 1) Relevant chemistry of concrete (12/26) C 3 S + (1.3 + x)h => C 13 SHx + 1.3CH C 2 S + (0.3 +x)h => C 13 SHx + 0.3CH 2C 3 A +21H =>C 4 AH 19 + C 2 AH 8 =>2C 3 AH 6 +9H C 3 A + 3CSH H => C 6 AS 3 H 32 < Ettringite 10/25/

14 1) Relevant chemistry of concrete (12/26) 10/25/

15 1) Relevant chemistry of concrete (13/26) Water water everywhere and not a drop to drink! 10/25/

16 1) Relevant chemistry of concrete (14/26) 10/25/

17 1) Relevant chemistry of concrete (15/26) 10/25/

18 1) Relevant chemistry of concrete (16/26) 10/25/

19 1) Relevant chemistry of concrete (17/26) 10/25/

20 1) Relevant chemistry of concrete (18/26) 10/25/

21 1) Relevant chemistry of concrete (19/26) 10/25/

22 1) Relevant chemistry of concrete (20/26) 10/25/

23 1) Relevant chemistry of concrete (21/26) Water forms; Nunavik region Canada, Inuit, the native people, have words for 53 types of snow. H 2 0, Dihydrogen oxide, Dihydrogen Monoxide, Hydrogen Oxide, Oxidane, steam, condensate, water, frost, slush, ice, snow 10/25/

24 1) Relevant chemistry of concrete (22/26) Potassium Oxide Sodium Oxide Gypsum 10/25/

25 1) Relevant chemistry of concrete (23/26) 10/25/

26 1) Relevant chemistry of concrete (24/26) Hydration (reacting cement and water) Tricalcium silicate + Water = Calcium silicate hydrate + Calcium hydroxide + heat 2Ca 3 SiO 5 + 7H 2 O => 3CaO. 2SiO 2. 4H 2 O + 3Ca(OH) kj Dicalcium silicate + Water = Calcium silicate hydrate + Calcium hydroxide + heat 2Ca 2 SiO 4 + 5H 2 O => 3CaO. 2SiO 2. 4H 2 O + Ca(OH) kj Calcium hydroxide + Fly Ash + Water => 10/25/

27 1) Relevant chemistry of concrete (25/26) And Hydration continues 2C 3 A + C 6 AS 3 H H => 3C 4 ASH 12 C 4 AF + 3CSH H => C 6 (A,F)S 3 H 32 + (F,A)H 3 C 4 AF + C6(A,F)S 3 H H => 3C 4 (A,F)SH 12 + (F,A)H 3 C 4 ASH CSH H => C6AS3H 32 Etc. Etc. 10/25/

28 1) Relevant chemistry of concrete (26/26) Concrete paste quality depends on available compounds & temperature. 10/25/

29 Ca 3 SiSO 4 CO 3 (OH) 6 12H 2 O, or 2) Thaumasite [Ca 3 Si(OH) 6.12H 2 O] (SO 4 )(CO 3 ), or CaSiO 3.CaCO 3.CaSO 4.15H2O 10/25/

30 2) Thaumasite (1/2) Thaumasite Sulfate Attack, (TSA); Forms in the 40 s F range. Friable concrete paste - 'mush. Can be broken with one s fingers removing aggregate. 10/25/

31 2) Thaumasite (2/2) Thaumasite, named in 1878 from the Greek word meaning to be surprised. SURPRISE! 1-1/2 polished section of degraded concrete from a highway structure in the United Kingdom, the white being Thaumasite Sulfate Attack. 10/25/

32 3) Temperature Measurement 10/25/

33 3) Temperature Measurement (1/5) Calorimetry, measures energy at a constant sample temperature. Simple explanation of Graph Zones; 1) Gypsum through solution incases clinker. 2) Alkalis turn solution to 13 ph. 3) Encasement dissolves, and clinker hydration begins. 4) Initial Aluminate reactions complete, strength reactions continue for 21 to 91 days slowing to insignificant strength gain. 10/25/

34 3) Temperature Measurement (2/5) Calorimetry 10/25/

35 3) Temperature Measurement (3/5) Calorimetry 10/25/

36 3) Temperature Measurement (4/5) Temperature logging, Field Calorimetry 10/25/

37 3) Temperature Measurement (5/5) Temperature logging, Field Calorimetry 10/25/

38 3) Gypsum chemistry note (1/1) Note: With warmer temperatures gypsum coats the clinker slower and less effectively. 10/25/

39 4) Mass Concrete 10/25/

40 4) Mass Concrete, DEF (1/3) The Trojan Horse of Sulfate Delayed Ettringite Formation (DEF) Initially ettringite is formed as expected in the plastic stage, however With temperatures over 150 F (65 C) ettringite decomposes as the sulphate is enticed to join with the C-S-H paste, which they do, however 10/25/

41 4) Mass Concrete, DEF (2/3) Trojan Horse of Sulfate Delayed Ettringite Formation When the atmosphere around them cools, the sulphate ions lose interest slowly migrate back to ettringite - this can take a month or two to complete. The ettringite is a larger volume crystal as it attracts water and acts as an internal wedge splitting the concrete apart with some cracks noted in literature exceeding 1 wide. 10/25/

42 4) Mass Concrete, DEF (2/3) Trojan Horse of Sulfate Delayed Ettringite Formation 10/25/

43 4) Mass Concrete, Thermal Shock (3/3) Thermal Shock Cracking Temperature differential over 35F (20C) 10/25/

44 5) Water as Temperature Control 10/25/

45 5) Water as Temperature Control (1/9) Evaporative cooling and SSD. Simple with a water use cost, but limited to the environmental conditions for evaporation, and the time before use to cool. 10/25/

46 5) Water as Temperature Control (2/9) Chilled water Cools water, to low 40 s F. Electricity predominate cost. Cooling concrete is limited to water replacement. Replace water; every 5F the chilled water is below concrete temperature provides -1F; -6 to -12F reduction. 10/25/

47 Ice 5) Water as Temperature Control (3/9) Ice can replace 90% of nonmoisture water, 10% water is needed to rinse in load. Minus 1F takes 7.5 pounds of replacement ice. SOLID ICE to be explained 10/25/

48 5) Water as Temperature Control (4/9) Ice The Dark Truth 32F ice can have the same effect as water at 32F, or up to an extra 144 degrees F of cooling. Temperature will not always tell us ice quality. 10/25/

49 5) Water as Temperature Control (5/9) Ice The Dark Truth 212 F xxxxxxxxxxxxxxxxxx 180 Btu/lb xxxxxxxxxxxxxxxxxxxx 32F to 212F 32 F xxxxxxxxxxxxxxx 970 Btu/lb xxxxxxxxxxxxx 144 Btu/lb 10/25/

50 5) Water as Temperature Control (6/9) Ice The Dark Truth ICE QUALITY TEST FORM Specific Weight Temperature Heat Total Btu's Lbs F Btu/(lbmF) Btu/lbm 32F base Initial Water Test Ice Combined Water Water 1.01 Latent Heat of Fusion 144 Ice 0.49 Test Ice Btu's -938 Test Ice water Btu's Test Ice Btu's at 32F -838 Test Ice Latent Btu's Test Ice Condition % /25/

51 5) Water as Temperature Control (7/9) Ice The Dark Truth Test Ice Btu's at 32F -838 Test Ice Latent Btu's Test Ice Condition % estimated Test Ice Original Temperature F 14.9 estimated solids in a cy estimated water in a cy Total Btu's to change 1 F 1130 adjust "sub 32F" until this is zero > 0 sub 32F F above 32F Btu reduction from Tested Ice > 1130 Estimated Lbs of Tested Ice to reduce 1 cy of concrete by 1 F > /25/

52 5) Water as Temperature Control (8/9) Ice The Dark Truth ICE QUALITY TEST FORM Specific Weight Temperature Heat Total Btu's Lbs F Btu/(lbmF) Btu/lbm 32F base Initial Water Test Ice Combined Water Water 1.01 Latent Heat of Fusion 144 Ice 0.49 Test Ice Btu's -938 Test Ice water Btu's Test Ice Btu's at 32F -838 Test Ice Latent Btu's Test Ice Condition % estimated Test Ice Original Temperature F 14.9 estimated solids in a cy estimated water in a cy Total Btu's to change 1 F 1130 adjust "sub 32F" until this is zero > 0 sub 32F F above 32F Btu reduction from Tested Ice > /25/2016 stimated Lbs of Tested Ice to reduce 1 cy of concrete by 1 F >

53 5) Water as Temperature Control (9/9) Ice The Dark Truth ICE QUALITY TEST FORM Specific Weight Temperature Heat Total Btu's Lbs F Btu/(lbmF) Btu/lbm 32F base Initial Water Test Ice Combined Water Water 1.01 Latent Heat of Fusion 144 Ice 0.49 Test Ice Btu's -938 Test Ice water Btu's Test Ice Btu's at 32F -838 Test Ice Latent Btu's Test Ice Condition % estimated Test Ice Original Temperature F 14.9 estimated solids in a cy estimated water in a cy Total Btu's to change 1 F 1130 adjust "sub 32F" until this is zero > 0 sub 32F F above 32F Btu reduction from Tested Ice > 1130 stimated Lbs of Tested Ice to reduce 1 cy of concrete by 1 F > 7.3 ICE QUALITY TEST FORM Specific Weight Temperature Heat Total Btu's Lbs F Btu/(lbmF) Btu/lbm 32F base Initial Water Test Ice Combined Water Water 1.01 Latent Heat of Fusion 144 Ice 0.49 Test Ice Btu's -450 Test Ice water Btu's Test Ice Btu's at 32F -295 Test Ice Latent Btu's Test Ice Condition % estimated Test Ice Original Temperature F 32.0 estimated solids in a cy estimated water in a cy Total Btu's to change 1 F 1117 adjust "sub 32F" until this is zero > 0 sub 32F F above 32F /25/2016 Btu reduction from Tested Ice > Estimated Lbs of Tested Ice to reduce 1 cy of concrete by 1 F > 20.0

54 6) Initial Curing (the last section) 10/25/

55 6) Initial Curing (14/14) 10/25/

56 6) Initial Curing (13/14) 10/25/

57 6) Initial Curing (12/14) (Right) In Cooler with R12; 124 F - 4,660 psi 10/25/

58 6) Initial Curing (11/14) Open to sun; 121 F 4,980 psi 10/25/

59 6) Initial Curing (10/14) (Left) Cooler in Air, Vented & Dry 104 F - 5,140 psi 10/25/

60 6) Initial Curing (9/14) Submerged in 5 gallon pail; 93F - 5,280 psi 10/25/

61 Shade; 6) Initial Curing (8/14) 90F - 5,450 psi 10/25/

62 6) Initial Curing (7/14) In Air Conditioned Board Room; 83 F - 5,370 psi 10/25/

63 6) Initial Curing (6/14) In Cooler, Vented and Water Bath; 78 F - 5,570 psi 10/25/

64 6) Initial Curing (5/14) 130 Initial Curing Trial August 18, Sun Insulated Pail H2O Air Cooler Air Boardrm Shade Sun Cool H2O Insulated Cool Dry Pail H2O Shade 80 Cooler H2O 70 Boardroom /25/

65 6) Initial Curing (4/14) Strengths sorted on Temperature*Hours (22 hrs, base 15F) F*Hrs 7d 28d A/C Cooler Bath Shade Pail w H2O Sun Cooler Insulate /25/

66 6) Initial Curing (3/14) Strengths sorted on Temperature Max F 7d 28d Cooler Bath A/C Shade Pail w H2O Cooler Sun Insulate /25/

67 6) Initial Curing (2/14) Strengths sorted on Temperature d 28d Linear (7d) Linear (28d) /25/

68 THE END 10/25/