"Road base material" is a broad construction category, not one single material. Depending on the pavement layer and project specification, it refers to GSB, WMM or a project-specific graded aggregate. OM Group explains the distinction below and supplies the applicable material across North and South Goa.
GSB and WMM are not presented as interchangeable anywhere on this page — each occupies a different, specified position in the pavement. See GSB vs WMM below.
It is a category term, not automatically one material. The pavement layer a project is building determines which material applies — the sub-base position calls for GSB, the base course above it calls for WMM — and the project specification determines the grading and physical properties required within either.
A supplier's job is to match the material to the specified application, not to sell whichever product is easiest to source. This page exists to make that match correctly: it explains the real distinction between GSB and WMM, and routes you to the page with the technical depth your project needs.
Actual pavement composition varies by pavement design, traffic loading, subgrade condition, climate, drainage and project specification — this is not presented as the universal structure of every road.
GSB and WMM are not interchangeable simply because both are used in road construction. They occupy different pavement positions and have different specification requirements.
| GSB | WMM | |
|---|---|---|
| Full form | Granular Sub-Base | Wet Mix Macadam |
| Pavement position | Sub-base, generally | Base course, generally, above GSB |
| Primary reference | MoRTH Clause 401 | MoRTH Clause 406 |
| Grading & physical requirements | Depend on the applicable grading / project specification | Depend on the project specification; a stricter, tighter-controlled grading than generic unclassified aggregate |
| Mixing | Blended to grading; moisture treatment project/process dependent | Plant mixing / controlled moisture, where applicable |
The full grading table, CBR context, compaction (MDD/OMC), testing parameters and comparisons live on the dedicated GSB page.
View GSB Specifications →The full grading envelope, AIV/LAA/flakiness requirements, production process and comparisons live on the dedicated WMM page.
View WMM Specifications →| Term | What it means | Typical role | Specification status | Can it automatically replace GSB/WMM? |
|---|---|---|---|---|
| Road base material | Category/search term for graded base or sub-base materials | Not one layer — depends on the material meant | None — depends on which material applies | — |
| GSB | Defined sub-base material | Sub-base | MoRTH Clause 401 | Yes, for the sub-base position |
| WMM | Defined base-course material | Base course | MoRTH Clause 406 | Yes, for the base-course position |
| Crusher-run | Uncontrolled mixed-size crusher output | Not a specified layer on its own | None | Only if blended to a specified grading first |
| Road metal | Regional/historical trade term, meaning varies | Varies | None universal | Only if it maps to a defined specification for the project |
| Single-size aggregate | One crushed fraction | An input, not a layer material | IS 383 | Only if blended to a curve |
| Boulders | Large individual stone | Different application entirely | Application-specific | No |
| Recycled aggregate | Processed demolition/construction waste aggregate | Application-specific | Emerging in Indian practice, project-specific acceptance | Only where the project specification explicitly permits it |
"Road metal" specifically carries genuine regional and historical variation in Indian construction trade usage — sometimes referring to crushed stone aggregate generally. It is not treated as automatically equivalent to GSB or WMM on this page. Recycled aggregate is treated neutrally — neither promoted nor dismissed; natural/crushed aggregate is not asserted as automatically superior.
There is no single universal "road base material" specification table — specifications depend on which actual material applies. Each material's real technical depth lives on its own page.
| Material | Primary reference | What determines the actual numbers |
|---|---|---|
| GSB | MoRTH Clause 401 | Grading, CBR, fines and density requirements depend on the applicable grading (I–VI) and project specification — see the GSB page |
| WMM | MoRTH Clause 406 | Grading, aggregate quality, moisture and compaction requirements depend on the project specification — see the WMM page |
| Graded aggregate | Project-specific specification | Grading, strength and durability requirements per the specific application |
Send these details to OM Group for a project-specific quotation, once you know which material — GSB, WMM aggregate, or another graded aggregate — your pavement layer requires.
Please provide:
If you already know your material is GSB or WMM aggregate specifically, the quote flow on each product page will route your enquiry directly.
OM Group combines aggregate production capability, material grading and project-focused supply to support road and infrastructure requirements across Goa. OM Group's aggregate production capability supports the graded material requirements of road and infrastructure projects — for the sub-base position (GSB) and for the crushed, graded fractions a WMM blend requires.
OM Group operates its own crushing and screening operation, producing the graded aggregate fractions used in road construction.
Material is matched to the pavement layer and project specification, rather than sold as a single undefined "road material."
6mm, 10mm, 12.5mm and 20mm fractions are all part of OM Group's crushed stone aggregate range, relevant across GSB, WMM and general road aggregate requirements.
GSB, WMM aggregate, graded aggregates, sand, boulders and Ready Mix Concrete can be coordinated on a single procurement relationship, rather than sourced from separate vendors.
This describes OM Group's confirmed crushing and screening operation, which produces the graded aggregate fractions feeding road construction supply generally. It does not describe GSB blending or WMM wet-mixing as OM Group's own operation — those steps, and what OM Group's role in each actually is, are addressed on the GSB and WMM pages respectively.
Sub-base and base-course material for highway pavement construction.
Road base and sub-base supply for state road projects.
Base and sub-base construction for rural road projects.
Road base material for urban road construction and rehabilitation.
Base-course and sub-base aggregate for industrial access roads.
Material supply for widening and reconstruction work.
Broader infrastructure and approach-road works requiring specified base or sub-base material.
Commercial and residential site-development roads.
Any civil project requiring specified road base or sub-base material.
Every application above is subject to pavement design and project specification — not every material is suitable for every application.
Price depends on material type (GSB, WMM aggregate, or another graded aggregate), grading, quantity, processing, source, transport distance, project location and availability. No fixed or invented rate is published — OM Group quotes against the specific requirement, once the material is identified.
Definition
Road base material is a broad construction term for graded granular materials used in the base or sub-base layers of a road pavement. Depending on the project specification, it may refer to GSB, WMM or another specified graded aggregate.
No. It is a category term, not one manufactured product. The specific material required depends on the pavement layer and the project's specification.
The pavement layer being constructed (sub-base or base course) and the project's contract specification together determine whether GSB, WMM or another graded aggregate applies.
"Road base material" is a broad category term; GSB is one specific, defined material within it, governed by MoRTH Clause 401 and used at the sub-base position.
"Road base material" is the broad category; WMM is one specific material within it, governed by MoRTH Clause 406 and used as the base course above GSB.
GSB
Yes — GSB is the granular sub-base layer, one of the specific materials the broader term "road base material" can refer to.
GSB (Granular Sub-Base) is a graded granular material placed and compacted over prepared subgrade to form the sub-base layer of a road pavement. Full detail is on the GSB page.
MoRTH Clause 401 is the principal Indian reference governing Granular Sub-Base material, grading and construction requirements.
GSB is generally used as the sub-base layer, above the subgrade and below the base course (typically WMM).
Yes. OM Group supplies GSB across Goa — see the GSB page for grading, testing and specification detail.
WMM
Yes — WMM is the base-course material above GSB, also within the broader "road base material" category.
WMM (Wet Mix Macadam) is a pavement base-course material made by mixing clean, crushed, graded aggregate with controlled water and compacting it, per MoRTH Clause 406. Full detail is on the WMM page.
MoRTH Clause 406 is the principal Indian reference governing Wet Mix Macadam production, grading and construction requirements.
WMM is generally used as the base course, above the granular sub-base and below the bituminous or surface layer.
Yes. OM Group supplies the crushed, graded aggregate fractions used in WMM production — see the WMM page for the full aggregate-supply detail.
Comparison
GSB is the sub-base layer, governed by MoRTH Clause 401; WMM is the base course above it, governed by Clause 406, more rigorously graded and plant-mixed with controlled moisture. They are not interchangeable.
No, not without engineering/specification approval — GSB and WMM serve different pavement positions with different grading and physical requirements.
No, for the same reason — the two materials occupy different, specified positions in the pavement structure.
Not automatically. Crusher-run is an uncontrolled mixed-size crusher output; it must be blended to a specified grading (GSB's or WMM's) before it meets either specification.
"Road metal" is a term with genuine regional and historical variation in Indian construction trade usage — it is not automatically equivalent to GSB or WMM.
Recycled aggregate is used in some jurisdictions and project specifications, where the applicable specification explicitly permits it. It is neither promoted nor dismissed here — acceptance is project- and specification-specific.
Technical
GSB (Granular Sub-Base) is generally used below WMM, forming the sub-base layer beneath the WMM base course.
GSB, governed by MoRTH Clause 401, is the standard material used as a road sub-base in Indian practice.
WMM, governed by MoRTH Clause 406, is generally used as the base course above the sub-base, subject to the project's pavement design.
CBR (California Bearing Ratio) measures the load-bearing resistance of a compacted material relative to a reference crushed-stone standard, used to evaluate whether a pavement layer provides the support the design requires.
Grading controls density, load distribution and drainage behaviour once a layer is compacted. Both GSB and WMM are specified to grading envelopes for this reason, not supplied as a single loose aggregate size.
Common tests include sieve analysis (grading), CBR, Aggregate Impact Value, Los Angeles Abrasion, flakiness and elongation, plasticity index and moisture/compaction testing — which apply, and to what limits, depends on whether the material is GSB, WMM or another specified aggregate.
Procurement
Confirm the pavement layer, the project/tender specification, whether GSB, WMM or another graded aggregate applies, the required grading, testing/documentation needs, quantity, delivery location and schedule, and who is responsible for final blending or processing.
The material required (GSB, WMM aggregate or another graded aggregate), quantity and unit, project location, required grading, tender/BOQ specification, testing requirement, delivery date, site access constraints and documentation requirement.
This depends on the project and contract — confirm explicitly whether the supplier or the contractor is responsible for final blending, mixing or processing before ordering, rather than assuming.
Quantity is calculated from your project's layer area, thickness and design — share your BOQ or drawings and OM Group can work from that, once the specific material is identified.
Yes. GSB, WMM aggregate, graded aggregates, sand, boulders and Ready Mix Concrete can be quoted and coordinated together on a single procurement relationship.
Grading/sieve analysis, relevant physical test results and delivery documentation are the common requests — availability depends on the specific material, source and project requirement.
Pricing
There is no fixed published rate — price depends on which material (GSB, WMM aggregate or another graded aggregate), grading, quantity and delivery location. Share your requirement with OM Group for current pricing.
Material type, grading, quantity, processing, source, transport distance, project location, current availability and project schedule.
No. OM Group quotes against the specific material and requirement rather than publishing a fixed or "starting from" rate.
OM Group
OM Group supplies across North and South Goa — specify your pavement layer (sub-base or base course) so the correct material, GSB or WMM aggregate, can be confirmed.
Yes — OM Group supplies GSB, WMM aggregate and graded crushed aggregate for road and infrastructure projects across Goa, matched to the applicable specification.
Yes. OM Group operates its own crushing and screening operation, producing the graded aggregate fractions used in road construction.
Yes, road base materials are supplied across North Goa, where applicable to the specific material.
Yes, road base materials are supplied across South Goa, where applicable to the specific material.
| Category | Road construction materials — GSB, WMM aggregate, graded aggregates |
| Applicable standards (reference) | MoRTH Clause 401 (GSB), MoRTH Clause 406 (WMM), project-specific for other graded aggregates |
| Grading | Confirmed against the specific material and project specification |
| Documentation | Available on request, depending on the specific material and project requirement |
| Availability and lead time | Confirmed against project requirement |
Tell OM Group your pavement layer and project specification — GSB, WMM aggregate, or another graded aggregate — and OM Group will confirm the appropriate supply requirement and commercial details.