A Review on the Effect of Crumb Rubber Addition to the Rheology of Crumb Rubber Modified Bitumen

Table 1

Important parameters in manufacturing CRMB according to several specifications around the world (adopted from [5]).

Properties	ASTM 2002	Caltrans 2006	Sabita 2007	Austroads 2007
Bitumen penetration (dmm)	Type 1: 85–100; Type 2: 120–150; Type 3: 200–300	120–150	60–100	85–100
Rubber sieve size (mm)	2.36	2.36	1.18	2.36
Rubber content (%)	≥15	18–22	18–24	15–18
Extender oil (%)	—	2.5–6	0–4	—
Calcium carbonate/talc (%)	0–4	—	0–4	—
Mixing temperature (°C)	177	190–220	180–220	195
Mixing speed (rpm)	—	—	3000	—
Mixing time (min)	45 + reaction	45–60	—	30–45