Updating Bituminous Stabilized Materials Guidelines Mix Design Report Phase II

More documents

Recommendations

Info

Figure J.22 illustrates the comparison of the strength reduction of BSMs from dry trafficking to wet trafficking conditions. The wet trafficking ITS shows a decrease in strength from dry trafficking ITS. However the comparison of the ITS values shows no significant difference for most of the BSMs tested, with some exceptions i.e. BSM-emulsion with Quartzites. This indicates that ITS test is not particularly sensitive to moisture effects. From previous analysis, see Section 4.1, the resistance to disintegration and ravelling by a long cured BSM-emulsion, indicated high moisture resistance. However, looking at the ITS values, the difference between highly moisture resistant to highly moisture susceptible BSMs is insignificant. This confirm the weakness of the ITS test, as reported previously by Hodgkinson, (2004). The lack of reliability and repeatability of the ITS test for use in ranking BSMs in terms of moisture susceptibility, should preclude its use for important applications of BSMs. ITS [kPa] 400 350 300 250 200 150 100 50 0 H+1C-E01 (long cured G2+0C-E02 G2+1C-E01 G2+0C-F01 H+0C-E01 BSM-Mixes Q+0C-E04 H+1C-E02 H+1L-E02 Wet Trafficked ITS Dry Trafficked ITS Figure J.22: Comparison of ITS results after wet and dry MMLS3 trafficking on different BSMs Further, comparison of the ITS values shows an increase in the moisture-sensitivity of the BSMs from initial study to additional study. However, it should be noted that in the initial study, wet trafficking terminated at 250 and 900 load applications after ravelling depth of 2mm to 4mm, while in the additional study, wet trafficking terminated at a 2500 and 45000 load application after ravelling-depth of 4mm to 12-14mm. Ravelling-depth of 4mm under the MMLS3 appears to be critical, see Figure J.20 and Figure J.21. At 4mm of ravelling BSMs experiences severe cohesion loss of stiffness reduction. Thereafter exponential disintegration occurs. It is appropriate to extend testing beyond 4mm of ravelling during moisture susceptibility testing with the MMLS3 trafficking. 28
Ravelling-Depth [mm 16 14 12 10 8 6 4 2 0 H+1C-E (long) G2+0C-E07 G2+1C-E01 G2+0C-F04 Ravelling-depth H+1C-E06 BSM - Mixes H+1L-E02 Q+0C-E08 H+0C-E07 Figure 23: Illustration of the Ravelling-Depth performance of BMS-Mixes after wet MMLS3 trafficking It is clear from the analysis presented in Figure 24 that early termination of trafficking might result into less sensitivity of the strength ratio. Moreover, late termination results to high sensitivity of strength ratio, hence causing irrational ranking of the BSMs. Figure 24 shows different shifts in strength reduction of BSMs of both premature and extended termination of MMLS3 trafficking. Wet Trafficked ITS Dry Trafficked ITS 400 ITS [kPa] 350 300 250 200 150 100 50 0 H+1C-E01 (long cured) G2+0C-E02 G2+1C-E01 G2+0C-F01 H+0C-E01 BSM-Mixes Q+0C-E04 H+1C-E02 H+1L-E02 Figure24: The shift indication between wet ITS and dry ITS after MMLS3 trafficking The selection criteria of BSM-mixes, according to South African Guideline TG2, shows that TSR values of greater that 75% is ranking GOOD resistance to moisture damage; while greater than 60% is ranking MEDIUM resistant to moisture damage and less than 50% is ranking POOR resistant to moisture damage. 29
Page 1 and 2: APPENDIX J Technical Memorandum Upd
Page 3 and 4: findings of the moisture damage tha
Page 5 and 6: Figure J.4: The measuring wheel of
Page 7 and 8: An electric calibration unit used t
Page 9 and 10: 2.2 BSMs for MMLS3 testing The inte
Page 11 and 12: Figure J.12: The side view of the b
Page 13 and 14: The set-up of the test before traff
Page 15 and 16: 3. TEST RESULTS The use of vinite o
Page 17 and 18: Table J.7: ITS results after wet an
Page 19 and 20: Table 11: Ravelling-depth after MML
Page 21 and 22: Table 15: Tensile Strength Retained
Page 23 and 24: The comparison of BSMs on Figure J.
Page 25 and 26: From Figure J.19 it can be seen tha
Page 27: 4.3 Saturation Level The moisture i
Page 31 and 32: From the study conducted in MIST de
Page 33 and 34: - No sign of significant initial de
Page 35: 5. BIBLIOGRAPHY ASPHALT ACADEMY. 20

Updating Bituminous Stabilized Materials Guidelines Mix Design Report Phase II

Create successful ePaper yourself

Delete template?

Save as template?