ROADGRIP Crumb Rubber Modified Bitumen
CRMB
IS : 15462: 2004 (ISI MARKED)
Description
Crumb Rubber Modified Bitumen (CRMB) is hydrocarbon binder obtained through physical and chemical interaction of crumb rubber (produced by recycling of used tyres) with bitumen and some specific additives.
Uses of Crumb Rubber Modified Bitumen:
- 1) Excellent Resistance to thermal and low temperature cracking.
- 2) Superior resistance to any form to permanent deformation.
- 3) To reduce viscosity at layout temperatures.
- 4) Superior resistance to any form to permanent deformation.
- 5) Overall improved performance in extreme climatic conditions.
- 6) Delay of cracking and reflective cracking.
- 7) Susceptibility to daily and seasonal temperature variations.
- 8) Does not require change in construction practices / machinery.
- 9) Cost effective.
Grades of CRMB
CRMB is available in CRMB 50, CRMB 55 & CRMB 60 Grades.
Requirements of Crumb Modified Bitumen (CRMB) [Crumb Rubber Based]
|
S.No |
Characteristics |
Grade and Requirements | Method of Test, Ref to | |||||
|
CRMB 50
|
CRMB 55
|
CRMB 60
|
IS-No.
|
Annex of IS 8887:2004
|
||||
| 1. | Penetrarion at 25°C, 0.1 mm,100g. 5s. |
<70 |
<60 |
<50 |
1203 |
-- |
||
| 2. | Softening point (R&B), °C, Min |
50 |
55 |
60 |
1205 |
-- |
||
| 3. | Flash point, COC, °C, Min |
220 |
220 |
220 |
1209 |
-- |
||
| 4. | Elastic recovery of half thread in ductilometer at 15°C, percent, Min |
50 |
50 |
50 |
-- |
A |
||
| 5. | Separation, difference in softening point(R&B), °C, Max |
4 |
4 |
4 |
-- |
B |
||
| 6. | Viscosity at 150°C, Poise |
1-3 |
2-6 |
3-9 |
1206(PART 1) |
-- |
||
| 7. | Thin film oven test and tests on residue:
(a) Loss in mass,percent,Max (b) Increase in softening point,°C, Max (c) Reduction in penetration of residue, at 25°C, percent, Max (d) Elastic recovery of half thread in ductilometer at 25°C,percent, Min |
1.0 7 35 50 |
1.0 7 35 50 |
1.0 7 35 50 |
9382 1205 1203 -- |
--
-- -- -- A |
||
|
"(1)Relevant to snow bound cold climate areas."
|
||||||||
Criteria for selection of CRMB:
| Maximum Atmospheric Temperature,°C | ||||
| Minimum Pravement Temperature, °C | <35°C | 35°C TO 45°C | >45°C | |
| <-10 | CRMB 50* | CRMB 55 | CRMB 55 | |
| -10 To 10 | CRMB 50 | CRMB 55 | CRMB 60 | |
| >10 | CRMB 55 | CRMB 55 | CRMB 60 | |
*Not below 15°C
Temperature of mixing and rolling shall be slightly higher than conventional bituminous mixes.
The Board range of temperature at different stage is as follows:
| Stage of Work | Indicated temperature °C |
| Binder at mixing | 165-185 |
| Mix at mixing plan | 140-160 |
| Mix at laying site | 130-150 |
| Rolling at laying site | 115-135 |