COARSE FRACTIONATED RECLAIMED ASPHALT PAVEMENT (FRAP) IN A TERNARY BLENDED CONCRETE

Transcription

1 COARSE FRACTIONATED RECLAIMED ASPHALT PAVEMENT (FRAP) IN A TERNARY BLENDED CONCRETE Jeffery Roesler, Ph.D. P.E. Professor Department of Civil and Environmental Engineering University of Illinois at Urbana-Champaign Tollway Open House August 20, 2013 Rosemont, IL

2 Acknowledgements Steve Gillen and Ross Bentsen Illinois State Toll Highway Authority Alexander Brand and Armen Amirkhanian (Ph.D. students); Ryan Smith; Daniel King; Pengcheng Shangguan University of Illinois at Urbana-Champaign Professor Imad Al-Qadi University of Illinois at Urbana-Champaign ARA, Inc. S.T.A.T.E. Testing and CTL Group Meyer Materials, Holcim, Lafarge

3 What is FRAP? Old asphalt pavement that has been milled, (washed), and fractionated (graded) Coarse FRAP contains 2.1% asphalt HMA has 5-6% Contains about 14% agglomerated particles

4 Why use FRAP in Concrete? Sustainability Disposal/hauling energy Natural resource depletion Carbon footprint Economy!! Excess stockpiles of coarse FRAP Fine FRAP (<#4 sieve) used by the Tollway as a liquid binder replacement when used with reclaimed asphalt shingles (RAS) Large stockpiles of coarse FRAP remain unused and take up space

5 Field Studies RAP or FRAP in Concrete Concrete with RAP Iowa (1976) two lift Austria (early 1990s to present) two lift, <10% RAP Kansas (1997) two lift, 15% RAP Illinois Tollway (2010 to present) composite, two lift, 20% RAP France (late 2000s to present) RCC, up to 100% RAP Other RAP studies in cement treated layers

6 I-94 Tollway Casting (October 2010) First pavement in Illinois containing a portion of RAP as coarse aggregate in concrete The mix contained 35% coarse FRAP and 20% fly ash The FRAP had 15% agglomerated particles

7 I-88 Tollway Casting (September 2012) Tollway s first two-lift pavement Bottom lift was a ternary blend (cement, slag, fly ash) with 21% coarse FRAP Bottom lift was 8 inches with 3.5-inch top lift Bottom lift had lower compressive and flexural strengths but similar fracture properties to the top lift

8 Literature Review RAP in Concrete Property Compressive strength Split tensile strength Flexural strength Modulus of elasticity Drying shrinkage Restrained ring shrinkage Coefficient of thermal expansion Abrasion Ductility Reaction as %RAP Increased Decrease Decrease Decrease Decrease Variable Results Decrease* Unaffected Increase Increase Property Shock absorbent properties Strain capacity Porosity Oxygen permeability Ultrasound pulse velocity Surface Absorption Slump Unit weight Air Content *The onset of cracking was delayed and the crack width was reduced Reaction as %RAP Increased Improve Improve Increase Increase Decrease Unaffected Variable Results Decrease Variable Results Kolias (1996) Delwar et al. (1997) Huang et al. (2005,2006) Hossiney et al. (2008, 2012) Bilodeau et al (2012)

9 Research at the University of Illinois ( )

10 Mix Designs Cement replacement 25% slag (Grade 100) 10% fly ash (Class C) Cementitious Content = 630 lb/yd 3 w/cm = 0.37 Coarse FRAP replacement 0, 20, 35, and 50% Chemical admixtures WRDA 82 mid-range water reducer Daravair 1400 air entraining agent

11 FRAP Gradation Conducted according to ASTM C136 FRAP gradation Does not meet IDOT CA limits Meets ASTM C33 Size 67 limits Meets IDOT CA11 when blended with dolomite Sieve FRAP Gradation ASTM C33 Size 67 Grading CA % / % / % / % # % # % # % - - # % - - # % - - # % - - # % - -

12 Compressive Strength Compressive Strength (psi) Concrete Age (days) % replacement of coarse aggregate 0% 20% 35% 50%

13 Flexural Strength (3 rd Point Loading) Flexural Strength (psi) % 20% 35% 50% % replacement of coarse aggregate

14 Split Tensile Strength

15 Elastic Modulus (Static) 7.0E E+06 Elastic Modulus Ipsi) 5.0E E E E+06 0% 20% 35% 50% 1.0E E+00

16 Dynamic Modulus at 21 C (70 F) 8.0E E Day Dynamic Modulus (psi) 7.0E E E E E E E E+06 % replacement of coarse aggregate 0% 21C 20% 21C 35% 21C 50% 21C 3.0E Frequency (Hz) 28 days

17 8.0E+06 4 C 8.0E C 7.0E E E E E E E E E % 4C 20% 4C 35% 4C 50% 4C 3.0E % 21C 20% 21C 35% 21C 50% 21C 28 Day Dynamic Modulus 8.0E E E E E E % 54C 20% 54C 35% 54C 50% 54C 54 C

18 Dynamic Modulus Reduction Percent Reduction in Modulus 0% 10% 20% 30% 40% 50% 0% -10% -20% -30% -40% -50% FRAP Content 20% 35% 50% 4C -19% 21C -22% 54C -22% 4C -31% 21C -31% 54C -34% 4C -46% 21C -46% 54C -49% 28 Day 4C 28 Day 21C 28 Day 54C -60%

19 Reduction at 28 Days FRAP Content 0% 10% 20% 30% 40% 50% 0% -10% Percent Reduction -20% -30% -40% -50% Static Modulus Dynamic Modulus 4C Compressive Strength Split Tensile Strength Flexural Strength -60%

20 AASHTO Free Drying Shrinkage -600 Shrinkage Strain (microstrain) % 20% 35% 50% Concrete Age (days)

21 Restrained Ring Shrinkage Shrinkage Strain (microstrain) % (Ternary) 0% (Ternary) CTL Group 0% (Plain Cement) No Cracks after 95+ days -160

22 Rapid Chloride Penetration Test % FRAP Sample Charge Passed Adjusted Charge Passed % Average % Average % FRAP 35% 50% Rating: Very Low to Low Test Charge Adjusted Charge Sample Age Passed Passed Average Average

23 Freeze-Thaw Durability After 300 Cycles Relative Dynamic Modulus Mix Average 0% FRAP % FRAP % FRAP % FRAP

24 Alkali Silica Reaction (ASR) Test 0.200% Expansion (%) 0.175% 0.150% 0.125% 0.100% 0.075% 0.050% 0.025% Limit at 0.16% Dolomite Sand FRAP Fines Post-Extracted FRAP 0.000% % Days in NaOH Solution Coarse+Fine aggregates are Group II by IDOT

25 Fracture Properties

26 Dirty FRAP Mixes Four mix types were made: Control (0%) Dirty FRAP (20%, 35%, and 50%) Washed Dirty FRAP (20%, 35%, and 50%) Fines (past #4) removed by washing Sieved Dirty FRAP (20%, 35%, and 50%) Fines (past #4) removed by dry sieving Tested for compressive and split tensile strength and 7, 14, and 28 days

27 Dirty FRAP Gradation 100% 90% 80% 70% Percent Passing 60% 50% 40% 30% 20% 10% 0% Sieve (mm) FRAP Dirty FRAP Washed Dirty FRAP

28 Compressive Strength 28 Days Day Compressive Strength (psi) % 10% 20% 30% 40% 50% Percentage of Coarse FRAP Dirty FRAP Sieved Dirty FRAP Washed Dirty FRAP

29 Lab Study Conclusions FRAP can used up to 35% to meet IDOT strength requirements for paving concrete Compression: 3500 psi at 14 days Flexural: 650 psi at 14 days Concrete strength/modulus decreases w/ FRAP content increase Restrained shrinkage is reduced for FRAP (50%) in concrete Chloride penetration is unaffected Virgin & FRAP concretes have same total fracture energy

30 Slab Casting Two-Lift ( )

31 Mix Design Virgin Mix 45% FRAP 100% RCA 45-55% FRAP-RCA Total Cementitious Cement 55% Slag 35% Fly Ash 10% Total Coarse Aggregate (SSD) Virgin Coarse Aggregate, CA11 (SSD) Virgin Intermediate Aggregate, CA16 (SSD) FRAP (SSD) RCA (SSD) Virgin Fine Aggregate (SSD) Water w/cm = Virgin mix had an optimized gradation Added synthetic macrofibers to 45% FRAP mix 0.43% by volume 45% cement replacement

32 Concrete Fresh Properties Description Slump (inches) Air Content (%) Unit Weight (lb/yd 3 ) 45% FRAP 7 8.5% % FRAP with fibers 5 12% % RCA 5 5.5% % FRAP-RCA % Virgin % 147.2

33 Compressive Strength Mix Average Compressive Strength (psi) Coefficient of Variation (COV) Percent Difference from Virgin 45% FRAP % -44% 45% FRAP with fibers % -60% 100% RCA % -26% 45-55% FRAP-RCA % -41% Virgin % --

34 Flexural Strength Mix Average MOR (psi) Coefficient of Variation (COV) Percent Difference from Virgin 45% FRAP % -25.7% 45% FRAP with fibers % -42.6% 100% RCA % -27.0% 45-55% FRAP-RCA % -24.6% Virgin % --

35 SLAB TESTING

36 Results Full Depth Concrete Which slab had the highest peak stress at failure? Mix Average MOR (psi) 45% FRAP % RCA % FRAP-RCA 593 Virgin 786 Failure Stress (psi) 1,345 1,170 1,465 1,185

37 Slab Results Slab Type Average Peak Load (kn) Percent Difference from Full Depth Virgin Two Lift Virgin over 45% FRAP % Full Depth 45% FRAP % Two Lift Virgin over 45% FRAP with fibers % Full Depth 100% RCA % Two Lift Virgin over 100% RCA % Full Depth 45-55% FRAP-RCA % Two Lift Virgin over 45-55% FRAP- RCA % Full Depth Virgin Average Result of Two Slab Tests

38 Slab Results

39 Single Edge Notched Beam (SENB) Two Parameter Fracture Model Jenq and Shah (1985) Compute K Ic and CTOD c Total fracture energy Hillerborg (1985)

40 Single Edge Notched Beam (SENB) EE ii = 6SSaa 0 gg 2 (αα 0 ) CC ii bb 2 tt gg 2 αα 0 = αα αα αα αα 0 2 EE uu = 6SSaa cc gg 2 (αα cc ) CC uu bb 2 tt Load (kn) C i C u CMOD (mm) KK IIII = 3 PP mmmmmm WW 0SS LL SS ππaa cc 1/2 gg 1 (aa cc /bb) 2bb 2 tt CCCCCCCC cc = 6SSaa ccgg 1 (aa cc /bb) EEbb 2 tt PP mmmmmm WW 0SS LL (1 ββ) 2 +( (aa cc /bb))(ββ ββ 2 ) 1/2

41 SENB Results Critical Stress Intensity Factor, K Ic (MPa-m 1/2 ) Critical Crack Tip Opening Displacement, CTODc (mm) Initial Fracture Energy, G Ic (N/m) Peak Load, P (kn) Total Fracture Energy, G F (N/m) 45% FRAP % FRAP with fibers 100% RCA FRAP RCA Virgin Highlighted Values are Statistically Different from the Virgin Mix

42 Fracture Energy and Strength Laboratory specimen strengths were lower for recycled aggregate concrete but the fracture energy was similar to virgin concrete Other studies have weakened or removed bonding and have found similar results (Guinea et al. 2002, Elices and Rocco 2008) Higher fracture energy may be due to: Absorption of energy by the asphalt on the FRAP Tortuosity of the crack as it travels around the FRAP and RCA rather than through the aggregate (like with virgin) Quality of the recycled materials Fracture energy of concrete linked to aggregate crushing value (i.e. quality) of RCA (Butler 2012)

43 What Do the Results Mean? Slab capacity is not accurately predicted by the beam flexural strength! Supports previous findings by Beckett and Humphreys 1989; Roesler 1998; Roesler et al. 2004, 2005, 2012; Kohler 2005; Rao 2005; Cervantes and Roesler 2009 Load capacity is underpredicted by a factor of 1.5 to 2.7! Attributed to geometric/material size effect (Ioannides 1997; Roesler 2006; Evangelista 2011) Despite a significant reduction in concrete beam/cylinder strengths, concrete with recycled aggregates can have similar slab flexural load capacities compared to virgin aggregate. Do we need to increase the slab thickness for FRAP concrete?

44 Questions / Comments

45 Concrete FRAP Tollway References 1. Brand, A., Amirkhanian, A., and Roesler, J. Flexural Capacity of Rigid Pavement Concrete Slabs with Recycled Aggregates, Illinois Center for Transportation Research Report ICT , University of Illinois, Urbana, IL, 108 pp. 2. Brand, A. Roesler, J., Al-Qadi, I., Shangguan, P., (2012), Fractionated Reclaimed Asphalt Pavement (FRAP) as a Coarse Aggregate Replacement in a Ternary Blended Concrete Pavement, Illinois Center for Transportation Research Report ICT , University of Illinois, Urbana, IL, 129 pp. 3. Brand, A., Amirkhanian, A., Roesler, J. (2013), Load Capacity of Concrete Slabs with Recycled Aggregates, ASCE T&DI Conference, Los Angeles, CA. 4. Gillen, S., Brand, A., Roesler, J., Vavrik, W. (2012), Sustainable Long-Life Composite Concrete Pavement for the Illinois Tollway, International Conference on Long Life Concrete Pavement, Seattle, Washington. 5. Brand, A., Smith, R., Roesler, J., Al-Qadi, I., Gillen, S. (2012), Fresh and Hardened Properties of Concrete with Fractionated Reclaimed Asphalt Pavement, International Conference on Concrete Pavement, Quebec City, Canada. 6. Bentsen, R. A., W. A. Vavrik, J. R. Roesler, and S. L. Gillen. Ternary Blend Concrete with Reclaimed Asphalt Pavement as an Aggregate in Two-Lift Concrete Pavement. Proceedings of the 2013 International Concrete Sustainability Conference, National Ready Mixed Concrete Association, San Francisco, California, 6-8 May 2013, 13 pp.