Performance-Related Tests of Recycled Aggregates for Use in Unbound Pavement Layers (2008)

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20 Laboratory Investigation RAP and RCP materials are generally used as an unbound structural layer. Thus, most of the laboratory tests were con- ducted on samples meeting a target gradation similar to a DGBL; a few tests were conducted on samples prepared to a gradation similar to an OGDL. The target gradations, shown in Table 4.1, are based on typical gradations for virgin mate- rials as provided in the Aggregate Handbook (2), which were adjusted based on results of the literature search and consid- eration of current practices. RAP and RCP materials meeting the target gradations were procured to allow testing of recycled materials with gradations similar to as-produced gradations. Table 4.2 shows the test conducted and the material combinations that were evaluated. Results of Laboratory Tests Grain Size Analysis All samples met the DGBL and OGDL gradation require- ments. The gradations with corresponding target for as- received RCP DGBL, RAP OGDL, and RAP DGBL are shown in Figures 4.1, 4.2, and 4.3, respectively. The gradations for the blended virgin aggregate DGBL and virgin aggregate OGDL samples are shown in Figures 4.4 and 4.5, respectively. RCP-GR-SC and RAP-GR-CO met the DGBL requirements as-received. These materials were blended to OGDL gradation. The constitutive aggregate in material referred to as RCP-LS- IL (in Figure 4.1 and subsequent figures) could have been dolomite or limestone. Figure 4.4 shows two virgin aggregate samples blended to meet DGBL requirements. Moisture/Density Relations Test specimens were prepared by compacting the RAP, RCP, and blends in accordance with test method D of AASHTO T 180. The OMC and the maximum dry densities for each ma- terial are listed in Table 4.2. As indicated, the OMCs of two ma- terials (50/50 blend of RCP-GR-SC DGBL#2 and RAP-GR-CO 50/50 OGDL re-blend) were changed from the laboratory- determined values because of the free moisture observed dur- ing repeated load triaxial testing. Static Triaxial Test The static triaxial test was conducted in accordance with AASHTO T 234 on each sample at confining stresses of 0, 5, and 15 psi (0, 34.5, 103.4 kPa) to determine the shear strengths at OMC. Samples were prepared to approximately 95 percent of the maximum dry density values listed in Table 4.2. Table 4.3 shows the maximum deviator stress at various confining stresses. Coarse DGBL gradation of virgin aggregate (DGBL#1) had a higher maximum deviator stress compared to the finer DGBL gradation (DGBL#2); virgin OGDL had a lower maxi- mum deviator stress compared to the DGBL gradations. Figure 4.6 shows the maximum deviator stress at 15 psi (103.4 kPa) confining pressure in ascending order. Overall, RCP samples had the greatest maximum deviator stress, followed by virgin aggregate materials and RAP samples. Materials with as-received DGBL gradations also had a higher deviator stress compared to material with OGDL as-received gradations. RAP and RCP with granite aggregate had a higher maximum deviator stress, followed by materials with gravel and limestone. Repeated Load Triaxial Test Results The repeated load triaxial tests were conducted to obtain a relative measure of the resistance of tested materials to permanent deformation. The test procedure, described in detail in Appendix B (available as NCHRP Web-Only Docu- ment 119 available on the webpage), is briefly discussed in Chapter 3. At each load level, 1,000 cycles were applied; the deviator stress for the first two load levels was 10 and 20 psi C H A P T E R 4 Laboratory Test Program and Test Results

21 Table 4.1. Percent passing for laboratory testing. Table 4.2. OMC and density data. Sieve size DGBL OGDL 1.50 inch (37.5 mm) 95 - 100 100 3/4 inch (19.0 mm) 70 - 89 70 - 95 3/8 inch (9.5 mm) 50 - 70 35 - 65 No. 4 (4.75 mm) 35 - 55 20 - 40 No. 16 (1.18mm) -- a 0 - 10 No. 30 (0.6 mm) 12 - 25 -- a No. 50 (0.3 mm) -- a 0 - 5 No. 100 (0.15 mm) -- a 0 - 3 No. 200 (0.075 mm) 0 - 7 0 - 1 a Not recorded Material Tested Tested Gradation Maximum Dry Density (pcf) OMC (percent) Virgin DGBL Blend#1 DGBL#1 150.1 7.4 Virgin DGBL Blend#2 DGBL#2 141.1 6.3 Virgin OGDL Blend OGDL 132.7 8.8 RAP-LS-MS OGDL 124.1 6.3 RAP-GV-LA OGDL 123.5 5.4 RAP-GR-CO DGBL#2 125.8 10.3 RCP-LS-IL DGBL#1 123.0 11.0 RCP-GV-LA DGBL#1 121.7 9.0 RCP-GR-SC DGBL#2 124.2 9.5 50/50 RAP-LS-MS OGDL 128.7 6.8 50/50 RAP-GV-LA OGDL 130.7 5.9 50/50 RAP-GR-CO DGBL#2 130.3 4.0 50/50 RCP-LS-IL DGBL#1 130.5 8.1 50/50 RCP-GV-LA DGBL#1 132.0 7.6 50/50 RCP-GR-SC DGBL#2 128.8 9.0 a RAP-GR-CO 100%OGDL re-blend OGDL 123.7 5.6 RAP-GR-CO 50/50 OGDL re-blend OGDL 127.5 3.5 RCP-GR-SC 100%OGDL re-blend OGDL 120.2 9.0 b RCP-GR-SC 50/50 OGDL re-blend OGDL 124.8 9.0 Notes: 1 pcf (pound/ft3) = 16.02 kg/m3 a OMC was lowered from 13.0 percent to 9.0 percent because of the free moisture observed during repeated load triaxial tests. b OMC was lowered from 15.4 percent to 9.0 percent because of the free moisture observed during repeated load triaxial tests. (68.9 and 137.9 kPa) and increased by 20 psi (137.9 kPa) there- after until failure (defined by a permanent axial strain of 10 percent) occurred or the load-frame limit was reached. Tests were conducted on triplicate OGDL samples prepared at OMC and on triplicate DGBL samples prepared at OMC in the saturated (wet) and unsaturated (dry) conditions. Results for repeated load triaxial tests conducted on RCP-GR-SC in the dry condition (unsaturated) are shown in Figures 4.7 and 4.8. Figure 4.7 shows the axial strain percent versus deviator stress relationships for the first and last load increments at the beginning and following the 1000th cycle of a repeated stress loading increment. Figure 4.8 shows the magnitude of axial

22 strain percent versus number of load cycles. Load increments, applied axial stress for each load cycle, and corresponding stress ratios are shown in Table 4.4. The stress ratio is defined as the ratio of major principal stresses (i.e., the ratio between vertical and horizontal stresses); it is equal to the ratio be- tween the axial applied stress and chamber confining pres- sure (i.e., σ1/σ3). Table 4.5 lists the stress ratios at which a particular per- manent strain (1, 3, 7, or 10 percent) occurred for each trip- licate sample. A higher stress ratio at lower permanent strain indicates a material with more resistance to perma- nent deformation. Stress ratios (average of three tests) obtained from dry (tests conducted at OMC) repeated load triaxial tests are Figure 4.1. Gradation results of RCP as-received DGBL samples. Figure 4.2. Gradation results of RAP as-received OGDL samples. 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Sieve Size Opening (inch) Pe rc en t P as si ng DGBL-Target RCP-GV-LA RCP-LS-IL Virgin DGBL blend#2 RCP-GR-SC 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Sieve Size Opening (inch) Pe rc en t P as si ng OGDL-Target RAP-GV-LA RAP-LS-MS

23 Figure 4.4. Gradation results of virgin aggregate DGBL-blended sample. 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Sieve Size Opening (inch) Pe rc en t P as si ng DGBL-Target Virgin-DGBL Virgin DGBL blend#2 Figure 4.3. Gradation results of as-received RAP DGBL samples. 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Sieve Size Opening (inch) Pe rc en t P as si ng DGBL-Target RAP-GR-CO shown in Figure 4.9 for RAP and Figure 4.10 for RCP and vir- gin aggregate. The material resistant to permanent deforma- tion has the highest stress ratio at the lowest permanent strain. In dry tests, 50-percent blends of RAP with virgin ag- gregate exhibited the highest permanent deformation resist- ance of RAP materials. RCP-GV-LA exhibited the highest overall permanent deformation resistance in the dry test, fol- lowed by virgin aggregate DGBL#1 and OGDL gradations. Figures 4.11 and 4.12 show the stress ratios (average of three tests) for wet and dry tests on RAP and virgin aggregate sam- ples (DGBL gradations) and on RCP (DGBL gradations). Virgin aggregate DGBL#1 exhibited the least permanent strain in dry repeated load triaxial tests, and virgin aggregate DGBL#2 the least permanent strain in wet tests. Of tested

24 Table 4.3. Failure deviator stress. Figure 4.5. Gradation results of virgin aggregate OGDL-blended sample. 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Sieve Size Opening (inch) Pe rc en t P as si ng OGDL-Target Virgin-OGDL Confining Pressure (psi) 0 5 15 Sample Identification Blend c (psi) Max. Deviator Stress, d (psi) Virgin DGBL Blend#1 DGBL#1 48.0 5.21 42.09 a 69.54 b 121.14 Virgin DGBL Blend#2 DGBL#2 49.0 2.08 11.20 44.21 106.40 Virgin OGDL Blend OGDL 45.0 2.78 27.17 a 50.59 b 83.51 RAP-LS-MS OGDL 38.5 4.17 26.86 a 41.10 b 65.30 RAP-GV-LA OGDL 39.0 2.78 23.56 a 37.82 b 61.73 RAP-GR-CO DGBL#2 41.0 2.08 11.20 32.20 63.96 RCP-LS-IL DGBL#1 46.0 5.56 39.16 a 66.36 b 103.20 RCP-GV-LA DGBL#1 48.0 1.39 25.39 a 55.06 b 96.05 RCP-GR-SC DGBL#2 52.0 2.78 19.26 56.33 129.58 50/50 RAP-LS-MS c OGDL -- -- -- -- -- 50/50 RAP-GV-LA c OGDL -- -- -- -- -- 50/50 RAP-GR-CO DGBL#2 42.0 1.74 6.77 33.52 69.74 50/50 RCP-LS-IL DGBL#1 50.0 2.08 12.45 50.65 106.22 50/50 RCP-GV-LA c DGBL#1 -- -- -- -- -- 50/50 RCP-GR-SC DGBL#2 50.0 2.08 10.18 50.30 109.63 RAP-GR-CO 100% OGDL re-blend OGDL 52.0 1.74 8.96 31.49 128.94 RAP-GR-CO 50/50 OGDL re-blend OGDL 42.0 1.74 6.18 31.17 68.25 RCP-GR-SC 100% OGDL re-blend OGDL 50.0 2.78 16.88 52.24 111.24 RCP-GR-SC 50/50 OGDL re-blend OGDL 49.0 1.74 12.40 55.53 103.63 Notes: 1 psi = 6.9 kPa a Maximum deviator stress at confining stress of 3 psi b Maximum deviator stress at confining stress of 7 psi c Not tested Φ σ

25 0 20 40 60 80 100 120 140 RAP-GV-LA RAP-GR-CO RAP-LS-MS RAP-GR-CO 50/50 R RAP-GR-CO 50/50 Virgin (OGDL) RCP-GV-LA RCP-LS-IL RCP-GR-SC 50/50 R RCP-LS-IL 50/50 Virgin (DGBL#2) RCP-GR-SC 50/50 RCP-GR-SC R Virgin (DGBL#1) RAP-GR-CO R RCP-GR-SC OGDL DGBL#2 DGBL#1 Maximum Deviator Stress, psi (at 15 psi confining stress) Figure 4.6. Maximum deviator stress in static triaxial tests. 0 20 40 60 80 100 120 140 160 180 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10 .0 10 .5 11 .0 Axial Strain (%) D ev ia to r S tre ss (p si) Strain First Load Increment Strain Last Load Increment Figure 4.7. Repeated load triaxial test results for RCP-GR-SC at OMC.

26 materials, the 50-percent blend of RAP-GR-CO with virgin aggregate was more resistant to permanent deformation in both the wet and dry repeated load triaxial tests compared to as-received RAP-GR-CO material. RCP-GV-LA exhibited the highest permanent deformation resistance in the dry tests of all RCP materials. In wet tests, the RCP-GR-SC material showed better resistance to permanent deformation. The number of load repetitions required to cause failure (10-percent permanent strain) was also used to evaluate re- sistance to permanent deformation (Figure 4.13). Virgin ag- gregate DGBL exhibited the highest resistance to permanent deformation. The test was terminated after 10,000 cycles at which the average permanent deformation was only 3.67 per- cent. Similar data are presented in Figure 4.14 for wet and dry tests on DGBL gradations. Resilient Modulus Test Results Resilient modulus (MR) was obtained using repeated load triaxial test data. MR values determined for different bulk stresses at an as-tested confining pressure of 15 psi (103.4 kPa) are shown in Figure 4.15. The relationship is expressed by the equation: where θ is bulk stress (psi) K1 and K2 are the experimental constant and coeffi- cient, respectively K1 and K2 values determined for the tested materials are listed in Table 4.6 in order of stiffness for the dry tests. The MR values were calculated for 100 psi (689.5 kPa) bulk stress using K1 and K2 values determined for dry and wet repeated load tri- axial tests. Virgin aggregate has the greatest stiffness, followed by the 50-percent blend of RAP-LS-MS, RCP-GV-LA, RAP- LS-MS, and 50-percent blend of RAP-GR-CO. Most of the materials tested in both and wet dry conditions did not show significant reduction in stiffness in the wet condition. In fact, the stiffness of RAP and RCP samples with granite in M =KR 1 K2θ 0 1 2 3 4 5 6 7 8 9 10 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500 7,000 7,500 8,000 8,500 9,000 9,500 10,000 No. of Cycles (N) A xi al S tra in (% ) 10% permanent strain reached at cycle #677 of loading sequence #9 Table 4.4. Stress ratios for repeated load triaxial test load cycles. Figure 4.8. Load repetitions versus permanent axial strain for RCP-GR-SC at OMC. Axial Stress Load Increment Load cycles psi kPa Stress Ratio 1 0 - 1,000 10 68.9 0.67 2 1,001 - 2,000 20 137.9 2.00 3 2,001 - 3,000 40 275.8 3.33 4 3,001 - 4,000 60 413.7 4.67 5 4,001 - 5,000 80 551.6 6.00 6 5,001 - 6,000 100 689.5 7.33 7 6,001 - 7,000 120 827.4 8.67 8 7,001 - 8,000 140 965.3 10.00 9 8,001 - 9,000 160 1,103.2 11.33 10 9,001 - 10,000 180 1,241.1 12.67

27 Load increment for strain achieved and stress ratio (SR) Material Sample Identification 1% 1 / 3 3% 7% 10% Dry Test #1 5 6.0 8 10.0 4.8% strain at cycle #10,000 Dry Test #2 5 6.0 10 12.7 3.2% strain at cycle #10,000 Dry Test #3 6 7.3 10 12.7 3.0% strain at cycle #10,000 Saturated Test #1 4 4.7 7 8.7 9 11.3 10 12.7 Saturated Test #2 4 4.7 7 8.7 10 12.7 10 12.7 Virgin DGBL Blend#1 Saturated Test #3 4 4.7 7 8.7 9 11.3 9 11.3 Dry Test #1 5 6.0 8 10.0 10 12.7 10 12.7 Dry Test #2 5 6.0 8 10.0 9 11.3 10 12.7 Dry Test #3 5 6.0 8 10.0 9 11.3 10 12.7 Saturated Test #1 5 6.0 7 8.7 8 10.0 8 10.0 Saturated Test #2 5 6.0 6 7.3 8 10.0 8 10.0 Virgin DGBL Blend#2 Saturated Test #3 5 6.0 7 8.7 8 10.0 8 10.0 Dry Test #1 6 7.3 8 10.0 9 11.3 9 11.3 Dry Test #2 5 6.0 8 10.0 9 11.3 9 11.3 Virgin OGDL Blen d Dry Test #3 5 6.0 8 10.0 9 11.3 10 12.7 Dry Test #1 3 3.3 5 6.0 7 8.7 9 11.3 Dry Test #2 3 3.3 5 6.0 7 8.7 9 11.3 Dry Test #3 3 3.3 5 6.0 7 8.7 8 10.0 RAP-LS- MS 100 o F Test 3 3.3 5 6.0 7 8.7 9 11.3 Dry Test #1 3 3.3 5 6.0 7 8.7 8 10.0 Dry Test #2 3 3.3 5 6.0 7 8.7 8 10.0 RAP-GV- LA Dry Test #3 4 4.7 5 6.0 7 8.7 8 10.0 Dry Test #1 3 3.3 5 6.0 8 10.0 10 12.7 Dry Test #2 3 3.3 5 6.0 8 10.0 10 12.7 Dry Test #3 3 3.3 5 6.0 8 10.0 9 11.3 100 o F Test 2 2.0 6 7.3 8 10.0 10 12.7 Saturated Test #1 3 3.3 5 6.0 8 10.0 10 12.7 Saturated Test #2 3 3.3 5 6.0 8 10.0 9 11.3 RAP-GR-CO Saturated Test #3 3 3.3 6 7.3 9 11.3 10 12.7 Dry Test #1 5 6.0 7 8.7 5.4% strain at cycle #8,800 Dry Test #2 5 6.0 8 10.0 6.9% strain at cycle #10,000 Dry Test #3 5 6.0 7 8.7 9 11.3 10 12.7 Saturated Test #1 5 6.0 8 10.0 9 11.3 10 12.7 Saturated Test #2 6 7.3 8 10.0 10 12.7 10 12.7 RCP-LS-IL Saturated Test #3 6 7.3 8 10.0 9 11.3 10 12.7 Dry Test #1 8 10.0 2.8% strain, cycle #9,001, at > load cell capacity Dry Test #2 8 10.0 10 12.7 4.5% strain at cycle #10,000 Dry Test #3 6 7.3 8 10.0 10 12.7 10 12.7 Saturated Test #1 5 6.0 6 7.3 7 8.7 8 10.0 Saturated Test #2 5 6.0 6 7.3 8 10.0 8 10.0 RCP-GV-LA Saturated Test #3 5 6.0 6 7.3 8 10.0 8 10.0 σ σ 1 / 3 σ σ 1 / 3 σ σ 1 / 3 σ σ Dry Test #1 5 6.0 7 8.7 9 11.3 9 11.3 Dry Test #2 5 6.0 7 8.7 9 11.3 9 11.3 Dry Test #3 5 6.0 7 8.7 9 11.3 10 12.7 Saturated Test #1 5 6.0 7 8.7 8 10.0 9 11.3 Saturated Test #2 5 6.0 6 7.3 8 10.0 9 11.3 RCP-GR- SC Saturated Test #3 5 6.0 7 8.7 8 10.0 9 11.3 Dry Test #1 4 4.7 6 7.3 8 10.0 9 11.3 Dry Test #2 4 4.7 6 7.3 8 10.0 9 11.3 Dry Test #3 4 4.7 6 7.3 8 10.0 9 11.3 50/50 RAP- LS-MS 100oF Test 4 4.7 6 7.3 8 10.0 9 11.3 Dry Test #1 4 4.7 6 7.3 8 10.0 8 10.0 Dry Test #2 4 4.7 6 7.3 8 10.0 9 11.3 50/50 RAP-GV-LA Dry Test #3 4 4.7 6 7.3 8 10.0 8 10.0 Table 4.5. Stress ratios for different permanent strain levels. (continued on next page)

28 as-received condition increased slightly under wet condi- tions. However, the stiffness of the 50-percent blend of RCP- GV-LA, virgin DGBL#1, and RCP-GV-LA was reduced by 15, 20, and 33 percent when tested in wet conditions, respectively, suggesting that these materials may be suscepti- ble to wet conditions. Toughness and Abrasion Resistance Aggregate toughness was determined using the Micro-Deval test (AASHTO TP 58-00), which provides an indication of an aggregate’s degradation potential. Test results are listed in Table 4.7; data reported for 50-percent blends were calculated using data from tests on as-received gradations. Durability Aggregate durability, when subjected to freeze-thaw cycles in the presence of moisture, was determined using the Cana- dian Freeze-Thaw test (MTO LS-614). Test results are listed in Table 4.7; test results for the 50-percent blends were calculated using data from tests on as-received gradations. Load increment for strain achieved and stress ratio (SR) Material Sample Identification 1% 3% 7% 10% Dry Test #1 4 4.7 6 7.3 8 10.0 9 11.3 Dry Test #2 4 4.7 6 7.3 8 10.0 9 11.3 Dry Test #3 4 4.7 6 7.3 8 10.0 9 11.3 100oF Test 3 3.3 5 6.0 8 10.0 9 11.3 Saturated Test #1 4 4.7 6 7.3 8 10.0 9 11.3 Saturated Test #2 4 4.7 6 7.3 8 10.0 9 11.3 50/50 RAP- GR-CO Saturated Test #3 4 4.7 6 7.3 8 10.0 9 11.3 Dry Test #1 4 4.7 7 8.7 9 11.3 10 12.7 Dry Test #2 5 6.0 7 8.7 9 11.3 10 12.7 Dry Test #3 5 6.0 7 8.7 9 11.3 10 12.7 Saturated Test #1 4 4.7 6 7.3 7 8.7 8 10.0 Saturated Test #2 5 6.0 6 7.3 8 10.0 9 11.3 50/50 RCP- LS-IL Saturated Test #3 5 6.0 6 7.3 7 8.7 8 10.0 Dry Test #1 5 6.0 7 8.7 9 11.3 9 11.3 Dry Test #2 5 6.0 7 8.7 9 11.3 10 12.7 Dry Test #3 5 6.0 7 8.7 8 10.0 8 10.0 Saturated Test #1 4 4.7 6 7.3 7 8.7 8 10.0 Saturated Test #2 5 6.0 7 8.7 8 10.0 9 11.3 50/50 RCP- GV-LA Saturated Test #3 5 6.0 6 7.3 8 10.0 8 10.0 Dry Test #1 5 6.0 7 8.7 10 12.7 10 12.7 Dry Test #2 4 4.7 7 8.7 9 11.3 9 11.3 Dry Test #3 4 4.7 6 7.3 8 10.0 9 11.3 Saturated Test #1 4 4.7 6 7.3 8 10.0 9 11.3 Saturated Test #2 4 4.7 6 7.3 8 10.0 8 10.0 50/50 RCP- GR-SC Saturated Test #3 4 4.7 6 7.3 7 8.7 8 10.0 Dry Test #1 3 3.3 5 6.0 7 8.7 9 11.3 Dry Test #2 3 3.3 5 6.0 8 10.0 9 11.3 RAP-GR-CO 100%OGDL re- blend Dry Test #3 3 3.3 5 6.0 7 8.7 9 11.3 1 / 3 σ σ 1 / 3 σ σ 1 / 3 σ σ 1 / 3 σ σ Dry Test #1 4 4.7 5 6.0 7 8.7 9 11.3 Dry Test #2 3 3.3 5 6.0 7 8.7 8 10.0 RAP-GR-CO 50/50 OGDL re-blend Dry Test #3 4 4.7 5 6.0 8 10.0 9 11.3 Dry Test #1 4 4.7 6 7.3 8 10.0 8 10.0 Dry Test #2 5 6.0 7 8.7 8 10.0 9 11.3 RCP-GR-SC 100%OGDL re-blend Dry Test #3 5 6.0 7 8.7 8 10.0 9 11.3 Dry Test #1 5 6.0 7 8.7 8 10.0 9 11.3 Dry Test #2 5 6.0 7 8.7 8 10.0 9 11.3 RCP-GR-SC 50/50 OGDL re-blend Dry Test #3 5 6.0 7 8.7 8 10.0 9 11.3 Table 4.5. (Continued).

29 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 RAP-LS-MS RAP-GR-CO RAP-GR-CO 100%OGDL reblend RAP-GV-LA RAP-GR-CO 50/50 OGDL reblend 50/50 RAP-LS-MS 50/50 RAP-GV-LA 50/50 RAP-GR-CO Virgin DGBL Blend#2 Virgin DGBL Blend#1 Virgin OGDL Blend Stress Ratio 10 percent 7 percent 3 percent 1 percent Strain 0.00 2.00 4.00 6.00 8.00 10.00 14.0012.00 50/50 RCP-GR-SC 50/50 RCP-LS-IL RCP-GR-SC 100%OGDL reblend Virgin DGBL Blend#2 RCP-LS-IL RCP-GR-SC 50/50 RCP-GV-LA RCP-GR-SC 50/50 OGDL reblend Virgin DGBL Blend#1 Virgin OGDL Blend RCP-GV-LA Stress Ratio 10 percent 7 percent 3 percent 1 percent Strain Figure 4.9. Stress ratios for dry triaxial tests on RAP samples. Figure 4.10. Stress ratios for dry triaxial tests on RCP and virgin samples.

30 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 RAP-GR-CO 50/50 RAP-GR-CO Virgin DGBL Blend#2 Virgin DGBL Blend#1 Stress Ratio 10 percent - wet 7 percent - wet 3 percent - wet 1 percent - wet 10 percent - dry 7 percent - dry 3 percent - dry 1 percent - dry Strain 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 Virgin DGBL Blend#2 Virgin DGBL Blend#1 RCP-GV-LA 50/50 RCP-GV-LA RCP-GR-SC RCP-LS-IL 50/50 RCP-LS-IL 50/50 RCP-GR-SC Stress Ratio 10 percent - wet 7 percent - wet 3 percent - wet 1 percent - wet 10 percent - dry 7 percent - dry 3 percent - dry 1 percent - dry Strain Figure 4.11. Stress ratios for dry and wet triaxial tests on RAP and virgin samples. Figure 4.12. Stress ratios for dry and wet triaxial tests on RCP samples.

31 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 Virgin DGBL Blend#1 RCP-GV-LA RCP-LS-IL Virgin DGBL Blend#2 50/50 RCP-LS-IL RAP-GR-CO 50/50 RCP-GR-SC Virgin OGDL Blend RCP-GR-SC 50/50 RCP-GV-LA 50/50 RAP-LS-MS 50/50 RAP-GR-CO RCP-GR-SC 50/50 OGDL reblend RAP-GR-CO 100%OGDL reblend RCP-GR-SC 100%OGDL reblend RAP-LS-MS RAP-GR-CO 50/50 OGDL reblend 50/50 RAP-GV-LA RAP-GV-LA Number of load repetitions for 10 percent permanent strain Figure 4.13. Number of load repetitions at 10-percent permanent strain (dry tests). Figure 4.14. Failure load repetitions for wet and dry tests. 0 2000 1000 3000 4000 5000 6000 7000 8000 9000 10000 RCP-LS-IL Virgin DGBL Blend#1 RAP-GR-CO RCP-GR-SC 50/50 RAP-GR-CO 50/50 RCP-LS-IL 50/50 RCP-GR-SC 50/50 RCP-GV-LA Virgin DGBL Blend#2 RCP-GV-LA Number of load repetitions for 10 percent permanent strain Wet Test Dry Test

32 Table 4.6. Resilient modulus data from repeated load triaxial testing. Figure 4.15. Resilient modulus test results for RCP-GR-SC. 10,000 100,000 10 100 1000 Bulk Stress, psi R es ili en t M od ul us , ps i Dry Tests Wet Tests MR at θ=100 psiSample Identification K1 K2 K1 K2 Dry Wet Virgin DGBL Blend#1 6,831 0.4897 12,487 0.3113 65,153 52,361 Virgin OGDL Blend 18,172 0.2657 -- a -- a 61,785 -- a Virgin DGBL Blend#2 13,348 0.3269 15,338 0.2876 60,139 57,672 50/50 RAP-LS-MS 10,567 0.3691 -- a -- a 57,836 -- a RCP-GV-LA 9,717 0.3870 36,947 0.0112 57,749 38,900 RAP-LS-MS 8,611 0.4008 -- a -- a 54,545 -- a 50/50 RAP-GR-CO 14,559 0.2760 15,010 0.2656 51,906 51,007 50/50 RAP-GV-LA 14,897 0.2666 -- a -- a 50,856 -- a RAP-GR-CO 100%OGDL re-blend 9,786 0.3560 -- a -- a 50,418 -- a 50/50 RCP-GV-LA 19,308 0.2074 23,343 0.1318 50,184 42,824 RAP-GR-CO 50/50 OGDL re-blend 9,337 0.3630 -- a -- a 49,692 -- a RCP-LS-IL 14,243 0.2713 25,452 0.1389 49,691 48,245 RAP-GR-CO 6,437 0.4411 8,459 0.3876 49,078 50,420 50/50 RCP-LS-IL 15,791 0.2432 24,468 0.1318 48,397 44,892 RAP-GV-LA 15,003 0.2534 -- a -- a 48,202 -- a 50/50 RCP-GR-SC 9,980 0.3263 15,576 0.2205 44,852 43,004 RCP-GR-SC 50/50 OGDL re-blend 10,172 0.3084 -- a -- a 42,097 -- a RCP-GR-SC 100%OGDL re-blend 21,591 0.1229 -- a -- a 38,024 -- a RCP-GR-SC 16,085 0.1848 21,774 0.1258 37,676 38,860 Notes: a wet tests on these materials were not included in laboratory investigation. 1 psi = 6.895 kPa

33 Frost Susceptibility Tube suction tests were conducted to characterize the mois- ture susceptibility properties of RAP, RCP, and virgin aggre- gate materials. The test measures the moisture affinity of a granular material by subjecting the test specimens to a 10-day capillary soak in a water bath, as described in Texas Test Method 144 E (12). Materials with a high affinity for water will imbibe signifi- cant amounts of water through suction, sometimes resulting in moisture contents higher than optimum after the capillary soaking period and substantial amounts of unbound, or “free,” water in the aggregate matrix. This unbound water will influ- ence the material’s ability to resist both traffic loading and freeze-thaw cycling. In this test, specimens are molded at OMC; RAP samples were more difficult to mold as compared to RCP samples. Figure 4.16 shows some of the molded samples. To monitor the amount of free water, the tube suction test measures the surface dielectric constant of the material, which is an indication of the free water in the aggregate sys- tem, and studies (12) have shown that materials with a sur- face dielectric constant value of greater than 10 after the capillary soak can, in some environments, exhibit poor per- formance in the field. Figure 4.17 shows the apparatus used to make the surface dielectric measurements. Plots of the surface dielectric constant value versus time for the tested materials are shown in Appendix C. Figures 4.18 and 4.19 show the data for RCP-GV-LA and RAP-GV-LA, respec- tively; RCP-GV-LA had rapid water absorption compared to RAP-GV-LA. Test results are listed in Table 4.8. Percent Loss Material Identification Micro-Deval Canadian Freeze- Thaw 50/50 RCP-LS-IL * 6.40 10.70 Virgin DGBL Blend#1 6.60 0.60 RAP-GV-LA 7.50 1.90 50/50 RCP-GV-LA * 7.80 1.40 Virgin OGDL Blend 8.10 0.90 50/50 RCP-GR-SC * 8.65 12.95 RCP-GR-SC 10.70 25.30 50/50 RAP-GR-CO * 12.65 5.05 50/50 RCP-GV-LA * 13.05 12.25 50/50 RAP-LS-MS * 13.20 0.80 RAP-LS-MS 18.30 0.70 RAP-GR-CO 18.70 9.50 RCP-LS-IL 19.40 22.00 RCP-GV-LA 19.50 23.90 Note: * Percent loss for 50-percent blends are averages of data for as-received gradations Figure 4.16. Molded RAP and RCP samples. Table 4.7. Percent loss for Micro-Deval and Canadian Freeze-Thaw tests. RAP-GV-LA RAP-LS-MS RCP-LS-IL RCP-GV-LA

34 Figure 4.17. Apparatus used to make surface dielectric measurements. Figure 4.18. Dielectric constant value curve with time for RCP-GV-LA. 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 0.0 50.0 200.0 250.0 150.0 100.0 A cc ep ta bl e M ar gi na l U na cc ep ta bl e Time (hours) Su rf ac e D ie le ct ri c C on st an t V al ue A cc ep ta bl e M ar gi na l 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 0.0 50.0 200.0 250.0 150.0 100.0 Time (hours) Su rf ac e D ie le ct ri c C on st an t V al ue U na cc ep ta bl e Figure 4.19. Dielectric constant value curve with time for RAP-GV-LA. Sample Identification Dielectric Constant Value RCP-GV-LA 14.3 Virgin DGBL Blend#1 9.6 50/50 RCP-GV-LA 13.5 50/50 RCP-LS-IL 21.6 50/50 RCP-GR-SC 10.0 Virgin DGBL Blend#2 10.6 RCP-LS-IL 16.3 50/50 RAP-GR-CO 3.7 RAP-GR-CO 3.3 RCP-GR-SC 12.1 Virgin OGDL Blend 8.0 50/50 RAP-LS-MS 3.2 RAP-LS-MS 2.1 50/50 RAP-GV-LA 3.6 RAP-GR-CO 100%OGDL re-blend 3.4 RAP-GR-CO 50/50 OGDL re-blend 3.9 RAP-GV-LA 2.0 RCP-GR-SC 50/50 OGDL re-blend 9.5 RCP-GR-SC 100%OGDL re-blend 10.4 Note: Acceptance criterion is dielectric constant value of 10 or less. Table 4.8. Dielectric constant values from the tube suction test.