Yu’s research indicated that the commercial asphalt plug joint binder can be fur- ther improved by the modification with thermoplastic rubber and rubber。 The addi- tion of thermoplastic rubber and rubber did not influence the penetration but increased the elongation at 5 °C significantly。 Brittle point temperature test also con- firmed the improvement on low-temperature property [30]。 Research done by Mo also indicated that the addition of 20 wt。% crumb rubber powder into SBS modified

Table 1

ASTM D6297-01 Standard Specification for APJs for bridges   [10]。

ASTM standards Required physical properties

Softening point, min D 36 83 °C

Tensile adhesion, min D 5329 700%

Ductility, min at 25 °C (77°F) D 113 400 mm

Penetration, Max at 25 °C, (77°F),150 g, 5   s D 3407 7。5 mm

Low temperature penetration, min at —18 °C (0°F), 200 g,60 s Flow, max 5 h, at 60 °C   (140°F)

D 3407 1。0 mm

3。0 mm

Resiliency, min–max at 25 °C (77°F) D 3407 40–70%

Asphalt compatibility D 3407 Pass

Recommended installation temperature range 182–199 °C

Safe  heating  temperature range 199–216 °C

Bond 3 Cycles at —7 °C (+20°F), 100%  Elong D 3405 Pass

Flexibility, at —23 °C (—10°F) D 5329 Pass

L。 Mo et al。 / Construction and Building Materials 45 (2013)  106–114 109

Table 2

Binder property requirements of UK standard for APJ  [7]。

Performance  characteristics Rubberized binder Polymer modified binder Test method

Cone  penetration  @  25 °C 25–45 dmm 25–90dmm BS 2499 Part 3

Softening point 70 °C minimum 80 °C minimum BS 2000 Part 58

Flow resistance 5%@45 °C maximum 5 mm@45 °C maximum BS 2499 Part 3

Extension test 3 cycles @ 0 °C 3 cycles @ 0 or —20 °C ASTM D1191

Table 3

Requirements on binder properties of Swiss design   guidelines。

Tests Requirement Test methods

Recovery with ductilometer @ 0 °C Lo P150 mm,  ERD P75% EN 13398:2003

Storage stability 63% EN 13399:2003