Quality Assurance Handbook for Rural Roads Volume-I - pmgsy

3. Section-400
408. Local materials for road construction
1. The local materials for rural road construction cover the locally available soils and aggregates
(including low grade/marginal aggregates) which are both, suitable and economical, for
incorporation as such or after suitable processing in lieu of the conventionally used high quality
materials.
2. It is always economically and technically prudent to use locally available materials as much as
possible instead of transporting conventional quality materials from long distances involving
uneconomical leads.
3. Usually some processing of the locally available materials is required to make their best use. This
Sub-section brings out the quality aspects of processing the locally available materials to use them
to the maximum potential.
4. Construction aspects for the use of these materials are similar to the conventional quality materials
and as such, reference to the relevant Sub-sections have been made as to their methodology for
construction.
5. To achieve the maximized use of locally available materials, it is essential that adequate soil and
materials surveys in the vicinity of the project site are carried out rather than only depending on
the well-established old pre-investigated quarries. The general guidelines regarding the field
surveys of locally available soils, moorums, gravels and aggregates are given in Annex 408.1.
A. Methodology
1. The representative samples of naturally occurring soils, moorums, gravels, soft/hard aggregates,
any industrial wastes and stabilizers like lime etc. should be subjected to laboratory testing. The
tests to be carried out should be relevant to their use in specific layer(s) for which reference may
be made to previous subsections.
2. When the locally available naturally occurring materials or industrial wastes do not meet the
engineering properties required for use in any layer of the pavement crust, appropriate processing
like modification/stabilization technique required to render these materials suitable for use in
any of the pavement layer(s) should be carried out as per the guidance given in Tables 408.1 and
408.2.
3. Where the naturally occurring Gravels/Soil-Gravel mixtures meet both the grading and plasticity
requirements for use in sub-base and base courses, these can be used as such. However, if these
materials are found to be deficient in grading only, processing by mechanical stabilization technique
can be resorted to so as to meet the grading requirements. Where these local materials are found
to be overly plastic, mixing with local sand in the required proportion is often the best solution.
4. Out of the possible alternative uses of the local materials as such or after suitable processing,
select the ones which are both, suitable and economical.
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