Research Article
Effect of Recycled Rubber on the Properties of Road Bitumen
Table 3
Properties of bitumen modified at 190°C.
| | Property | Sample no. | | 1 | 2 | 3 | 4 | 5 | 6 |
| | Penetration at 25°C (0.1 mm) | 71 | 69 | 66 | 69 | 60 | 68 | | Softening point (R&B) (°C) | 52.0 | 56.4 | 57 | 55.6 | 55.0 | 53.7 | | Penetration index | 0.20 | 1.10 | 1.10 | 0.90 | — | — | | Fraass breaking point (°C) | −20 | −22 | −22 | −23 | −14 | −17 | | Elastic recovery at 25°C (%) | 69 | 74 | 75 | 72 | — | — | | Stability (values of penetration top/penetration bottom) (0.1 mm) | 71/76 | 75/81 | 80/83 | 82/83 | — | — | | Delta penetration (difference between top and bottom of the tube) (0.1 mm) | 5 | 6 | 3 | 1 | — | — | | Stability (R&B top/R&B bottom) | 50/58.6 | 49/58.4 | 48.8/50.2 | 48.2/51.2 | — | — | | Delta R&B (°C) | 8.6 | 9.4 | 1.4 | 3.0 | — | — | | Retained penetration at 25°C after RTFOT (%) | 60.2 | 61 | 60.4 | 61.4 | — | — | | Increasing of softening point R&B after RTFOT (°C) | 8.2 | 4.6 | 3.4 | 5.8 | — | — | | Mass change after RTFOT (%) | −0.16 | −0.16 | −0.13 | −0.12 | — | — | | Cohesion energy at 5°C (J/cm2) | 3.5 | 3.6 | 4.8 | 4.1 | — | — | | Cohesion energy at 10°C (J/cm2) | 2.0 | 2.3 | 2.5 | 2.0 | — | — | | Maximal tensile force at 5°C (N) | 25.3 | 21.0 | 32.0 | 27.0 | — | — | | Maximal tensile force at 10°C (N) | 12.9 | 14.6 | 16.0 | 10.4 | — | — |
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