Updating Bituminous Stabilized Materials Guidelines Mix Design Report Phase II

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The disintegration of BSMs due to wet trafficking might occur due to quality of aggregates, cohesion and adhesion of aggregates-binder interface, void on the mixes, saturation level, temperature etc. The following subsection discusses findings on disintegration and ravelling results from MMLS3 testing. 4.2 Disintegration and ravelling of BSMs Monitoring of the disintegration and ravelling of progressing MMLS3 test under wet trafficking consists of two types. Firstly, the surface disintegration, which monitored visually on spalled aggregates at intermittent times during trafficking. The spalling of aggregates can cause punchering of the wheel as well as vinite layer during trafficking. Secondly, cohesion loss or stiffness deterioration during wet trafficking is measured as cumulative ravelling using profilometer. The profilometer is placed transversely in seven (7) different positions along the beam i.e. on each specimen being tested. Data on cumulative ravelling is recorded and present in Tables shown in Section 3.1, and 3.2. The disintegration during MMLS3 test shows that, wet trafficking creates more damage in terms of cohesion loss or stiffness reduction than dry trafficking. The comparison made at the same number of load applications and testing temperature. No sign of significant initial densification occurred on BSMs. However, stiffness of the trafficked materials decreases as number of load application increases. This suggests that cohesion loss has occurred under traffic and the damage is aggravated by pore pressures in the presence of water. As an example of the ravelling results, Figure J.18 illustrates transverse ravelling profile measured on wet trafficking. Forty five thousand (45000) cumulative wheel loads were applied during this test. -2 Ravelling-depth [mm] -0.5 0 50 100 150 200 250 1 2.5 4 5.5 7 8.5 0 200 3000 7000 15000 25000 40000 45000 Profilometer position 4 Figure J.18: Transverse ravelling measured during wet MMLS3 trafficking 24
From Figure J.19 it can be seen that predominant mode of distress is loss of material. The materials move along and sides of the wheel path as loss of cohesion or stiffness reduction progresses. Less moisture susceptible mix Moisture susceptible mix Loss of material along and side the wheel path Figure J.19: Loss of material of different BSMs on wet MMLS3 trafficking after 45000 load application Figure J.20 shows the typical failure mechanism of BSMs under wet trafficking. The comparison made between BSM-emulsion with Hornfels-RAP and addition of active filler at fully saturation. The BSMs with Hornfels-RAP with addition of 1% lime is relative moisture susceptible compared to BSM-emulsion with Hornfels-RAP with addition of 1% cement. Looking at the testing procedures, the conclusion can be drawn that the established protocol can identify and rank BSMs in terms of moisture related damage. It is clear from the test results the use of the APT Device (MMLS3) has potential for identification of the varying degrees of distress that BSMs suffer under wet trafficking. From this result, a reliable correlation of the MMLS3 Device and MIST device testing system is achievable. A further observation on the disintegration and ravelling results, prove that cohesion loss and stiffness reduction develop progressively. Figure J.20 shows ravelling-depth development of BSM-emulsion of Hornfels-RAP and BSM-emulsion of Quartzites without addition of active filler. The insight on failure mechanism of these mixes is that severe reduction of cohesion or stiffness occurred after 1500 load application. Thereafter an exponential increase in loss of materials occurred. However, some briquettes that spalled during cutting show an early failure, indicating that smoothness of the test surface can influence results. 25
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: The comparison of BSMs on Figure J.
Page 27 and 28: 4.3 Saturation Level The moisture i
Page 29 and 30: Ravelling-Depth [mm 16 14 12 10 8 6
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

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