BORAL ASPHALT
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Stone Mastic Asphalt (SMA)
ASPHALT PRODUCTS 2018 EDITION
Specially designed gap graded Stone Mastic Asphalt
delivers high performance wearing surfaces.
Background Recognised Value Advantages of SMA
Stone Mastic Asphalt was developed Stone Mastic Asphalt is a thin asphalt • Industry acknowledged deformation
in Germany during the mid 1960’s. surfacing mix, which has very good resistance
The original purpose was to provide rut resistance properties and excellent
• Good skid resistance
a surfacing that offered maximum durability compared to standard asphalt.
resistance to damage by studded It can also be used as a base course mix. • Good durability (slow ageing)
tyres. Over the years it has proved While it is primarily used for heavily due to higher binder content
to have a high resistance to plastic trafficked roads and is the preferred
• Good low temperature performance
deformation from heavy vehicle loads surfacing in some countries, SMA can
at high temperatures, while at the same be used for all types of pavements. • Wide range of applications
time exhibiting good low temperature It is basically a gap-graded asphalt mix, • Longer service life than dense
properties. (primarily for surface courses), with a graded asphalt
high proportion of coarse aggregate
• Reduced road surface noise
which interlocks to form a stone skeleton
to resist permanent deformation. • Good surface texture
The mix is filled with a mastic of bitumen
and fillers, to which fibres are added in • Good flexibility and resistance
order to provide adequate stability to the to fatigue
binder and prevent drainage of binder • Suitable for all traffic volumes,
during transport and placing. particularly for high traffic volumes
In addition to its structural capabilities, and heavy traffic
the SMA surface has a rough texture • Can reduce rehabilitation and therefore
which offers a good skid resistance over the disruption to traffic.
time, and can reduce road surface noise.
Stone Mastic Asphalt (SMA)
ASPHALT PRODUCTS
Although SMA is more expensive than Pneumatic tyred rollers are not used. Typical mix components
Dense Graded Asphalt [due to a higher
binder content, use of a modified binder
The SMA mix should not be opened to by volume
traffic until it has cooled.
and fibres and reduced production rate]
it can be more economical in the long SMA surface course mixes show excellent Dense Stone
term by reducing rehabilitation and results in terms of being particularly stable Graded Mastic
extending service life. and durable in traffic areas with high loads
and under a wide variety of weather Coarse
The design philosophy revolves
conditions. Aggregate
around developing a strong stone skeleton
with a high stone content, high bitumen SMA has good deformation resistance
and mortar content and a binder carrier. properties with reports of 30 to 40%(1)(2)
Layer thicknesses are usually four times improvement over dense graded asphalt.
the nominal stone size of the mix (eg. Size There are also reports of an increased
10mix gives a 40mm layer thickness). life of 20% (sometimes 30 to 40%)(1)(2)
over conventional mixes on very heavily
Modified binders are often used in
trafficked roads.
heavy duty situations to increase the Fine
resistance to permanent deformation Tests have shown that noise levels from Aggregate
and to increase service life. SMA are 1 to 3dB(A) less than dense
graded asphalt.(2) With such good, long Filler
SMA is produced in an asphalt plant in the
term performance and acceptance
same manner as dense graded asphalt. Bitumen
overseas, there appears no doubt its
However, SMA requires tighter quality
popularity will continue as the demands
control in both production and laying. Air Voids
of modern day traffic increase.
Conventional asphalt paving equipment
is used and a light tack coat is normally
applied. Compaction is usually carried
out by 4 to 6 passes of a steel drum roller.
(1) Performance of Stone Matrix Asphalt Pavements in Maryland, Michael, Burke, Schwartz, 2002.
(2) European experiences in the design, manufacture and placement of StoneMatrix Asphalt, Marissa Nicolls, DMR-QLD 2002.
Boral website: Contact us: Product images are indicative only,
and should be used as a guide.
Visit the Boral website for the full range of At Boral we are committed Copyright Boral Construction
Boral products: www.boral.com.au to excellence in service so Materials Limited ACN 000 614 826
for further information – all rights reserved 2011–2018.
Asphalt information: please contact:
For asphalt news and information visit: NSW (02) 8801 2000
www.boral.com.au/asphalt VIC 1300 132 964
For asphalt locations around Australia go QLD (07) 3268 8011
to: www.boral.com.au/locations SA (08) 8425 0400
WA (08) 9458 0400
or visit: www.boral.com.au/contact
SDS: A Safety Data Sheet is available upon request by contacting Boral Asphalt customer service.
Images in this brochure are only representative of Boral products and the appearance and effect that may be achieved by their use.
Particular projects may require the use of specific construction techniques or products. Boral recommends obtaining technical advice
prior to construction. Boral, the Boral logo, boral.com.au, Build something great are trade marks or registered trade marks of Boral
Limited in Australia. ©Copyright Boral Construction Materials Limited ACN 000 614 826 – all rights reserved 2018. BCC 15514_1/18 BLA
