645 
Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986 
Remote sensing for survey of material resources of highway 
engineering projects in developing countries 
R.L.Nanda 
Nigerian Building & Road Research Institute, Lagos 
ABSTRACT: Ttie third world countries are embarking on big projects of road construction so as to meet the 
needs of developing economy. But the conventionally used hard stones are invariably not available at or near 
the site of construction. These have to be transported from long distances, thereby increasing the cost of 
construction. With a view to achieving economy, emphasis is being laid on the judicious utilization of 
locally available materials such as soil, gravel, laterite and calcrete (calcareous aggregates). These low 
grade aggregates though not as hard as conventionally used hard—stones, still have adequate mechanical 
strength to be made use of in the bases and sub-bases of the pavement. 
For optimum utilization of these regional deposits, inventory of material resources is a pre-requisite, which 
can be prepared expeditiously only by the application of remote sensing technique, even if the region is 
inaccessible. 
Using this scientific technique, attempts have been made to conduct survey of soil for engineering purposes 
and identification and location of sub-surface calcrete, commonly occuring in the arid and semi-arid regions 
of India and Nigeria, covering an area of about 13,000 sq. km. and 18,000 sq. km. respectively. The timely 
information about the location of locally available materials will go a long way in economising the cost of 
road construction in future development programmes. 
The paper discusses the remote seising techniques adopted during the experimental surveys, their relative 
usefulness and limitations, particularly for the developing countries. 
1. INTRODUCTION 
Large scale road construction programme is being 
embarked in developing countries so as to meet the 
needs of developing economy. The known sources of 
aggregates are getting progressively depleted due to 
the expanding construction activity. Furthermore, 
there are certain areas where construction of network 
of roads is in progress but the conventionally used 
hardstone is not available at or near the site of 
construction. It has to be transported from long 
distances thereby increasing the cost of construc 
tion. With a view to achieving economy in the road 
development programme, emphasis is being laid on the 
judicious utilisation of locally available materials 
such as soil, gravel, laterite and calcrete (calcare 
ous aggregate). These regional deposits though not 
as hard as conventionally used hard stone still have 
adequate mechanical strength to be made use of in 
the bases and sub-bases of the pavement. 
In order to utilize these local deposits to the 
maximum possible extent, an inventory of material 
resources is a prerequisite for obtaining information 
regarding type, location and extent. This type of 
inventory can be prepared either by ground survey or 
by the application of scientific technique of remote 
sensing. With the conventional method of ground sur 
vey the procedure is not only time consuming, but also 
laborious as the whole area is to be traversed and 
numerous bore-holes are to be made. Moreover the 
progress of survey is liable to the handicapped by 
inaccessibility to land due to lack of roads, paths 
or existence of dense vegetation and high sand dunes. 
Such is not the case when the technique of remote 
sensing is applied as the land is brought to the 
laboratory and studied overthere without any 
hinderance. 
2. SCOPE AND LIMITATIONS OF REMOTE SENSING IN 
HIGHWAY ENGINEERING 
2.1 Scope 
The technique of remote sensing is of special 
interest and of great assistance in the field of 
highway engineering. Some of the important aspects 
are as follows: 
(i) Materials survey 
(ii) Route location 
(iii) Field performance of highway pavement. 
It is the first aspect which has greater significance 
in a developing country where the road system is to 
be developed at a fast rate in order to meet the 
needs of expanding economy. It is essential to 
systematise the knowledge of road making materials, 
including soils available in the country. The 
investigation is likely to reveal the presence of 
large quantity of low grade aggregates which can 
be judiciously utilised either as such or after 
scientifically processing. This amounts to consi 
derable saving in the cost of material as well as 
transportation. The materials survey with the help 
of remote sensing can be conducted not only with 
less manpower but also much faster. The timely 
information about the location of locally available 
construction materials will go a long way in 
economising the cost of road construction in future 
development plans. 
2.2 Limitation 
Remote sensing is a composite term which includes 
many types of sensing. But for the purpose of 
engineering soil and material survey conducted in 
India and Nigeria the techniques have been limited 
to the followina three types: 
(i) Aerial photographs (black and white) 
(ii) SLAR imagery (side looking airborne radar) 
(iii) Landsat imagery (photographic)