Guia De Uso Del Otta Seal (En Ingles)

Return address:
Directorate of Public Roads
Road Technology Department
P.O. Box 8142 Dep
N-0033 Oslo
Norway

ISBN 82 – 91228 – 03 – 5
ISSN 0803 - 6950

93

Publication

no

A Guide
to the Use of
Otta Seals

Road Technology Department (NRRL)

Publication no. 93

By Charles Øverby

A Guide to the Use of
Otta Seals

Directorate of Public Roads
Road TechnologyDepartment
International Division
Oslo, August 1999

Front cover design:
Front cover picture:
Layout:
Photo:
Editing-/production co-ordinator:
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Edition:

ISBN
ISSN

Svein Aarset
Charles Øverby, NPRA
Jan Edvardsen, ICG, Oslo, Norway
Charles Øverby, NPRA. T. Rees, Haas Consult, Botswana
Charles Øverby, NPRA
Allkopi AS, Oslo, Norway
3000

82 – 91228 – 03 – 5
0803 - 6950Reproduction of extracts from this Publication may be made
subject to due acknowledgement of the source. Although this
Publication is believed to be correct at the time of printing, the
Norwegian Public Roads Administration does not accept any
contractual, tortious or other form of liability for its contents or
for any consequences arising from its use. Anyone using the
information containedin the Publication should apply their own
skill and judgement to the particular issue under consideration.

2

Norwegian Public Roads Adm.

A Guide to the Use of Otta Seals

PREFACE
The first Otta Seal surfacing was constructed in Norway during the years 1963 - 1965 based on an innovative
and experimental approach. The main objective was to develop a method that could effectivelyimprove the
quality of the gravel roads to a cost equal to the gravel road maintenance. In 1965 the Norwegian Road Research
Laboratory had successfully developed a sprayed bituminous seal using graded gravel and soft binder at a relatively
high binder content. During the next 20 years, more than 12000 km of unpaved roads were surfaced by the Otta
Seal method, comprising about 20% of the totalpaved road network in Norway. The Otta Seal rapidly proved to
be very cost-effective and durable, and its performance much better than originally expected.
During the next 25 years Norwegian engineers has been promoting this type of sprayed bituminous seal at
various parts of the world, adopting appropriate specification, matching the local environment. The reported
experiences have without doubtbeen very successful ranging from areas of freezing cold to hot/wet and dry/very
hot climate. In many cases, strict adherence to the more conventional standards for bituminous surfacings would
either prohibit the project or made it unnecessarily costly. However, the lack of information regarding the Otta
Seal, properties, design (previously the design of Otta Seals was based on empiricalmethods, rather than the
more rational methods used for Chip Seals), construction and performance and the reluctance from the construction
industry to embrace new technology, has so far limited the use of this type of sprayed bituminous surfacing.
The two main objectives of this Publication is to provide the following:

l

Provide a ready, practical reference for the engineers and technicians whodesign and execute the sprayed
bituminous work.

l

Summing up 25 years experiences with the global use of the Otta Seals providing technical evidence and
economical justifications that the Otta Seals have no other limitations than other types of sprayed bituminous
seals.

It is my sincerely hope that this Publication will provide the required confidence in using this type of innovativetype of sprayed bituminous surfacing, as well as to be a guidance to the practitioners, governmental engineers
and technicians, contractors and consultants in situations that will favour this type of sprayed bituminous surfacing.

Oslo, 10th of August 1999

Olav Søfteland
Director General of Public Roads

This Publication no 93 from the Road Technology Department at the Directorate of...