Updating Bituminous Stabilized Materials Guidelines Mix Design Report Phase II

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4. ANALYSIS AND DISCUSSION OF RESULTS The objective of this section is to provide an overview on the findings of MMLS3 testing and subsequent ITS testing on wet and dry trafficked BSMs. The results obtained in APT device (MMLS3) and ITS used to establish possible correlation or trend between MMLS3 and MIST device testing system. The relationships between these devices also provide an insight of moisture related damage on different BSMs. Through the results, screening of the different BSMs in terms of moisture susceptibility defined. In an attempt to observe the performance of proposed MMLS3 test set-up for the BSMs, the initial study tests conducted with different test variables. These variables include 680kPa tyre pressure, 1.2kN wheel load, and 7200wheel per hour, with installation of vinite layer at the top of briquettes. The additional tests however, were carried out at new testing variables to correlate with the variables predetermined for the MIST device. The new variables were 420kPa, 1.8kN, and speed of 7200wheel per hour. The combination of new variables allowed acceptable number load application of MMLS3 trafficking and correlation with MIST device testing system on BSMs. The study of different factors related to moisture damage on the BSMs was investigated. These factors described in subsequent subsections. 4.1 Load application on BSMs The impact of moisture on pavement performance differs depending on the type of pavement, loading condition, temperature, and degree of saturation. A BSM in pavement layer is used as base or subbase, in order to enable load distribution in the structure. The interaction of the surface traffic and pore pressure developed in BSMs due to ingress of water is complex. In this study, the MMLS3 test variables were scaled down to correlate with MIST device. Due to reduction of tyre pressure and wheel load, the installation of vinite or rubber mat layer used to ensure the pore pressure effect not reduced in the BSMs during trafficking. The installation of vinite or rubber mat does not simulate field conditions, but merely minimises direct abrasion of the wheels on the BSM-layer and help screening BSMs in terms of moisture related damage. As outlined above, different BMSs were investigated during MMLS3 and MIST testing in the laboratory. Figure J.17 present a comparison of BSMs performance on load application to failure in wet condition, at 25 o C, 420kPa, 1.8kN, and speed of 7200wheel per hour. 22
The comparison of BSMs on Figure J.17 show that BSM-emulsion with long curing condition performed extremely good with 100 000 loads application, compared to other BSMs tested after standard accelerated curing. Cumulative no. of load application BSM-<strong>Mix</strong> 100000 10000 1000 100 10 1 0.1 0.01 H+1C- E (long) G2+0C- E07 G2+1C- E01 G2+0C- F04 H+1C- E06 H+1L- E02 Q+0C- E08 H+0C- E07 No of load application 100000 900 250 250 40000 40000 2500 2500 Ravelling-depth 0.06 1.71 2.9 3.6 0.01 3.98 12.38 14.54 Figure J.17: Cumulative number of load applications to failure of BSMs in wet condition at 25 o C, 420kPa, 1.8kNa and speed of 7200wheel per hour. Further comparison in Figure J.17, the BSMs with crushed Hortnfels (G2) materials carry less load applications than BSMs with Hornfels-RAP and Quartzites materials. The impact of addition of active filler is obvious. BSMs with no addition of active filler fail at a lower number of load applications (i.e. 250 to 2500) compared to BSMs with the addition of active filler, which fails at 45000. However, looking at the values of load applications on crushed Hornfels (G2) materials, they seem unexpectedly low. This might have occurred due to initial set-up of higher tyre pressure, as well as the spalling of specimen indicated in Figure J.14. It is counter-intuitive that the crushed Hornfels (G2) material with additional of cement fails at less load applications i.e. 250 than the crushed Hornfels (G2) material with no cement i.e. at 900 load applications. As stated previously, sample preparation has significant impact on the mechanical performance of the BSMs. In conclusion, the comparison of BSMs indicates that long cured mixes have significant resistance to moisture damage compared to accelerated cured mixes. BSM-foam or BSMemulsion mixes with crushed Hornfels (G2) material seem to be moisture susceptible compared to BSM-emulsion with Hornfel-RAP or Quartzites. Addition of active filler has proven to add resistance of the BSMs to moisture susceptibility. 23
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: Table 15: Tensile Strength Retained
Page 25 and 26: From Figure J.19 it can be seen tha
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

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