Use of Stone Mastic Asphalt on Airport Pavements - aaptp

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In summary, the high stone content forms a skeleton type mineral structure which <strong>of</strong>fers high resistance to deformation due to stone to stone contact, which is independent <strong>of</strong> temperature. The fibres added to the binder stiffen the resulting mastic and prevent draining <strong>of</strong>f during storage, transportation and laying <strong>of</strong> SMA. The mastic fills the voids, retaining the chips in position and has an additional stabilising effect as well as providing low air voids and thus highly durable asphalt (AAPA, 1993). 2.4 <strong>Stone</strong> <strong>Mastic</strong> <strong>Asphalt</strong> Materials Selection <strong>of</strong> materials is important in SMA design. The coarse aggregate should be a durable, fully crushed rock with a cubicle shape (maximum <strong>of</strong> 20% elongated or flat aggregate). Fine aggregate should be at least 50% crushed. Filler can be ground limestone rock, hydrated lime or flyash. In general, materials <strong>of</strong> similar quality to those used in dense graded asphalt wearing courses are required for the same conditions. Figure 2.2 shows the individual components <strong>of</strong> SMA. Figure 2.2 <strong>Stone</strong> <strong>Mastic</strong> <strong>Asphalt</strong> Components 9
2.4.1 Aggregates 2.4.2 Binder The strength, toughness and rut resistance <strong>of</strong> SMA depends mostly on the aggregate in the mix being 100% crushed aggregate with good shape (cubicle) and stringent limits for abrasion resistance, flakiness index, crushing strength and where appropriate, polishing resistance. Fine aggregate requirements vary from 50% crushed/50% natural sand but trending to 75%/25% to even higher proportions <strong>of</strong> crushed material. The sand used must be crushed sand as the internal friction <strong>of</strong> the sand fraction largely contributes to the overall stability <strong>of</strong> SMA. <strong>Stone</strong> mastic asphalt contains more binder than conventional dense graded mixes, with percentages ranging from about 6.0% up to 7.5%. Heavy duty performance is usually enhanced with polymers and fibres. These help to provide a thick aggregate coating to the aggregate, and the prevention <strong>of</strong> drain down during transportation and placement. Class 320 bitumen is commonly used for most applications. Multigrade binders and polymer modified binders (PMB) can be used to give even greater deformation resistance. The type <strong>of</strong> PMB most commonly used with SMA is styrene butadiene styrene (SBS) which is an elastomeric polymer type. Brown et al (1997a) reported that SMA incorporating an SBS PMB produced more rut resistant mixes than SMA with unmodified binder. Superior fatigue lives are also reported as a consequence <strong>of</strong> using an SMA/SBS system. Modified binders are used for several reasons, including: (a) to increase the resistance to permanent deformation, (b) to increase the life span <strong>of</strong> the pavement surface, (c) to reduce application and damage risks especially in cases <strong>of</strong> very thin layers, and 10
Page 1 and 2: Reproducing any part of</st
Page 3 and 4: Abstract Traditionally in Australia
Page 5 and 6: Acknowledgments The research associ
Page 7 and 8: Table of Contents
Page 9 and 10: 4.3.5 St Angelo’s Airport - Ennis
Page 11 and 12: Abbreviation Meaning SBS Styrene Bu
Page 13 and 14: This report will consider the use <
Page 15 and 16: The BCA (1998) defines SMA as “a
Page 17 and 18: APRG (1998) indicates that the esse
Page 19: 2.3 Stone
Page 23 and 24: 2.5 Advantages and Disadvantages <s
Page 25 and 26: Table 2.1 Relative Performance <str
Page 27 and 28: Justification for the use o
Page 29 and 30: In New South Wales, only limited tr
Page 31 and 32: Recognition of its
Page 33 and 34: Table 3.2 cont. Summary of<
Page 35 and 36: 3.2.6 China Shen et al (undated) re
Page 37 and 38: This section looks at where SMA has
Page 39 and 40: All tests carried out concerning we
Page 41 and 42: Conclusions from Norway Lange, et a
Page 43 and 44: The first 1,400 metres of</
Page 45 and 46: Cologne At Cologne Airport, SMA has
Page 47 and 48: 4.2.14 Faeroe Islands 4.2.15 Austri
Page 49 and 50: 4.3.2 Prestwick Airport Sto
Page 51 and 52: The binder used in the SMA was a C1
Page 53 and 54: 5. Cairns International Airport Tri
Page 55 and 56: In May 1999, a further SMA trial wa
Page 57 and 58: 6. Sydney International Airport Tri
Page 59 and 60: STONE MASTIC ASPHALT TRIAL LOCATION
Page 61 and 62: 7. Discussion Research into the use
Page 63 and 64: During May 1999, a SMA trial was un
Page 65 and 66: 8. Conclusion The use of</s
Page 67 and 68: References 1. AAPA (1998),
Page 69 and 70: 19. van der Heide, J.P.J. (1996), <
Page 71 and 72:
39. Wonson, K. (1996) SMA - The Eur
Page 73 and 74:
Appendix A This appendix contains c
Page 75 and 76:
Photo 1 Laying of
Page 77 and 78:
Photo 5 Typical joint between pavin
Page 79 and 80:
Photo 8 Typical open textured area
Page 81 and 82:
Appendix C This appendix contains t
Page 83 and 84:
The following is an example <strong
Page 85:
Appendix E This appendix contains d
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