Characterization of TX Active Cement Brett Trautman Field Materials Eng. Two-Lift Paving Open House Route 141, St. Louis County September 28, 2010
History Late 2008, Director heard a presentation on Green cement Materials Division asked to investigate Found company in United States Late 2009, Director requested that a trial section be constructed Early 2010, met with Essroc - Decided to use two-lift paving Early June 2010, laboratory batching done - To ensure similar performance
Aggregates Materials Coarse: Weber North, St. Louis L.S. Ledge 2-9 Fine: Capital Sand, Missouri River, Class A Admixture Air Entrainment: Euclid AEA-92 Water Reducer: n/a Hydraulic Cements Control: LaFarge, Type I Experimental: Essroc, TX Active
Mix Design Criteria Cement Content = 560 lbs/cu yd w/c Ratio = 0.44 Design Air Content = 6.0% Percent Fine Aggregate (by volume) = 40% Used for both mixes (control and experimental) MoDOT
Laboratory Batching Four mixes batched Evaluate Freeze/Thaw Resistance - Batched June 8, 2010 1) Control Mix w/type I 2) Experimental Mix w/tx Active Evaluate Scaling Resistance - Batched June 22, 2010 3) Control Mix w/type I 4) Experimental Mix w/tx Active
Appearance Concrete utilizing TX Active is much lighter in color than normal concrete - Reflects sunlight better - Retain less heat Concrete feels slimy to the touch
Fresh Properties: - Air Content - Unit Weight - Slump Testing
Testing Harden Properties - Compressive Strength - Flexural Strength - Rapid Chloride Permeability - Permeable Voids - Freeze/Thaw Durability - Linear Traverse - Salt Scaling Test
Modified Flexural Strength Concerns about chemical reaction and bonding potential between TX Active cement and regular Type I cement Bottom lift consisted of concrete using Type I cement; top lift consisted of concrete using TX Active cement 1 2 3
Modified Flexural Strength Excellent results - Achieved bond - No indication of a chemical reaction - No voids along interface - Great flexural strength (832psi)
Resistance of Concrete to Rapid Freezing and Thawing AASHTO T 161, Procedure B Molded 3 beams Beam Size - 3 ½ x 4 ½ x 16 Test started after 35 days of curing Beams cured in lime water
Determine durability factor Fundamental transverse frequency Oscilloscope Driver Variable Frequency Oscillator Pickup
Other Tests Length Change Weight Change Length Calibration Length Change Specimen Weight
Compressive Strength of Cylindrical Concrete Specimens AASHTO T 22 Molded 3 cylinders Cylinder size - 6 x 12 3, 7, 28, & 56-day breaks
Flexural Strength of Concrete AASHTO T 97 Molded 3 beams 3 1/2 x 4 1/2 x 16 beams 35-day break; when freeze/thaw testing started Note: Testing freeze/thaw beams after testing
Microscopical Determination of the Air-Void System in Harden Concrete Determine the air void system of the harden concrete (bubble size and spacing) Concrete freeze/thaw durability effected by air void system ASTM C 457 Procedure A - Linear Traverse Molded 1 cylinder Cylinder Size: 4 x 8 Manual Method
Harden Concrete Testing Manual System 4 top 4 bottom 1
Electrical Indication of Concrete s Ability to Resist Chloride Ion Penetration: Determine permeability of concrete AASHTO T 277 Molded 1 cylinder Cylinder Size - 4 x 8 Test at 28 & 56 days
Test Procedures Chloride Penetration top middle bottom 4 2
Density, Absorption, and Voids in Harden Concrete Determine permeable voids of concrete ASTM C 642 Molded 1 cylinder Cylinder Size: 6 x 12 Tested at 28 & 56 days
Test Procedures Permeable Voids 2 4 top middle bottom - not tested
Scaling Resistance of Concrete Surfaces Exposed to Deicing ASTM C 672 Molded 2 panels Chemicals Panel Size: 12 x 12 x 3 50 cycles 14 days moisture curing & stored in air for 14 days
Test Procedures Scaling
Test Results
Fresh Concrete Properties Mix Air Content*, % Slump, in. Unit Weight, lbs/ft 3 Air Content**, % Control (Mix #1) 8.2 1 1/2 139.1 9.1 Experimental (Mix #2) 8.0 1 3/4 140.8 8.0 Control (Mix #3) 8.3 2 139.5 8.5 Experimental (Mix #4) * Pressure Method ** Calculated from unit weight 6.9 1 1/4 141.6 7.3
3-day Compressive Strength Difference = 195 psi Compressive Strengtht, psi 3400 3350 3300 3250 3200 3150 3180 3375 Control (Mix #1) Experimental (Mix #2) 3100 3050 Freeze/Thaw Evaluation 3-day Compressive Strength 3450 3450 3400 Compressive Strength, psi 3350 3300 3250 3200 3150 3220 Control (Mix #3) Experimental (Mix #4) Difference = 230 psi 3100 Scaling Evaluation
7-day Compressive Strength Difference = 95 psi 3960 3940 3960 Compressive Strength, psi 3920 3900 3880 3860 3840 3820 3800 3865 Freeze/Thaw Evaluation Control (Mix #1) Experimental (Mix #2) 7-day Compressive Strength 3900 Compressive Strength. psi 3890 3880 3870 3860 3880 3890 Control (Mix #3) Experimental (Mix #4) Difference = 10 psi 3850 Scaling Evaluation
28-day Compressive Strength Difference = 290 psi Compressive Strength, psi 4950 4900 4850 4800 4750 4700 4650 4600 4550 4500 4940 4650 Freeze/Thaw Evaluation Control (Mix #1) Experimental (Mix #2) 28-day Compressive Strength 4850 4840 Compressive Strength, psi 4800 4750 4700 4650 4680 Control (Mix #3) Experimental (Mix #4) Difference = 160 psi 4600 Scaling Evaluation
56-day Compressive Strength 5250 Difference = 370 psi 5200 5150 5210 Compressive Strength, psi 5100 5050 5000 4950 4900 4850 4800 4840 Control (Mix #3) Experimental (Mix #4) 4750 4700 4650 Scaling Evaluation
Linear Traverse Test Results Air Spacing Specific Voids per Mix Content Factor Surface Inch Control (Mix #1) 6.92 0.003 1399 24.2 Experimental (Mix #2) 6.23 0.003 1435 22.3 - Compressive strength low due to the number of voids per inch
35-day Flexural Strength 840 Difference = 29 psi Flexural Strength, psi 830 820 810 800 798 827 832 Control (Mix #1) Experimental (Mix #2) Modified (Mix #1 & #2) 790 780 Freeze/Thaw Evaluation
28-day Permeability Difference = 708 coulombs 4000 3500 3670 Permeability, coulombs 3000 2500 2000 1500 1000 2962 Freeze/Thaw Evaluation Control (Mix #1) Experimental (Mix #2) 28-day Permeability 4000 3500 3902 Permeability, coulombs 3000 2500 2000 3120 Control (Mix #3) Experimental (Mix #4) 1500 Difference = 782 coulombs 1000 Scaling Evaluation
56-day Permeability Difference = 196 coulombs 2450 2400 2433 Permeability, coulombs 2350 2300 2250 2200 2150 2100 2050 2237 Control (Mix #1) Experimental (Mix #2) 56-day Permeability 2000 Freeze/Thaw Evaluation 3000 Permeability, coulombs 2900 2800 2700 2600 2500 2400 2903 2453 Control (Mix #3) Experimental (Mix #4) Difference = 450 coulombs 2300 2200 Scaling Evaluation
TX Active Study - Permeability (AASHTO T277) Control (#1) Experimental (#2) Control (#3) Experimental (#4) Permeability, Coulombs 4000 3500 3000 2500 2000 1500 1000 500 0 28-day 56-day Time, days
28-day Permeable Voids Difference = 0.6 % 11.9 11.8 11.9 11.7 Permeable Voids, % 11.6 11.5 11.4 11.3 11.2 11.1 11.0 11.3 Scaling Evaluation Control (Mix #3) Exoerimental (Mix #4) 56-day Permeable Voids 12.0 11.8 12.0 Permeable Voids, % 11.6 11.4 11.2 11.0 11.1 Control (Mix #3) Experimental (Mix #4) Difference = 0.9 % 10.8 10.6 Scaling Evaluation
Freeze/Thaw Testing Difference = 0.4 % 95.0 95.0 94.9 Durability Factor, % 94.8 94.7 94.6 94.6 Control (Mix #1) Experimental (Mix #2) 94.5 94.4 Freeze/Thaw Evaluation
Scaling Resistance Control Mix Rating = 0+ (40 cycles) Rating = 0+ (40 cycles)
Scaling Resistance Experimental Mix Rating = 0+ (40 cycles) Rating = 0+ (40 cycles)
Cement Test Results Physical Analysis Cement Fineness, Vicat, min. Autoclave, Compressive Strength, psi Type cm 2 /g Initial Set Final Set % 3-day 7-day Type I 347 129 204-0.01 3990 5450 TX Active 536 93 195 0.02 3380 4090 Required --- Min. 45 Max. 375 Max. 0.8 Min. 1740 Min. 2760
Cement Test Results Chemical Analysis Cement Insoluble Silicon Aluminum Ferric Calcium Magnesium Type Residue, % L.O.I., % Dioxide, % Oxide, % Oxide, % Oxide, % Oxide, % Type I 0.47 2.76 20.61 4.68 2.87 63.29 1.34 TX Active 4.19 2.44 19.03 4.53 3.16 59.06 2.65 Required Max. 0.75 Max. 3.0 --- --- --- --- Max. 6.0
Summary Comparable freeze/thaw resistance Comparable scaling resistance TX Active yields lower permeability TX Active yields high early age strength TX Active yields lower strength at later age Comparable air void system produced Permeable voids slightly higher for TX Active Exceeds minimum requirements for PCCP
Questions brett.trautman@modot.mo.gov (573) 751-2926