Water Bound Macadam
(IS 2386 / MORTH Clause 404)

Complete physical and mechanical testing of Water Bound Macadam (WBM) coarse aggregate and screenings as per MORTH Clause 404 and IS 2386 — verifying grading, aggregate impact value, abrasion, flakiness, elongation and water absorption for road base and sub-base layer acceptance.

Overview

What is the Water Bound Macadam (WBM) Testing?

Water Bound Macadam (WBM) is one of the oldest and most widely used road construction techniques in India — a pavement base or sub-base layer consisting of crushed coarse aggregate mechanically interlocked by rolling and bound by screenings and water. The crushed aggregate (Grading 1, 2 or 3 per MORTH) is spread, compacted and grouted with fine screenings and water to form a dense, stable pavement layer.

At Global Lab, WBM testing is conducted as per MORTH Clause 404 and IS 2386 covering particle size distribution for both coarse aggregate and screenings (grading 1: 90–45mm, grading 2: 63–45mm, grading 3: 53–22.4mm), Aggregate Impact Value (AIV ≤40%), Los Angeles Abrasion Value (LAA ≤40%), flakiness index (≤15%), elongation index (≤15%), specific gravity and water absorption — mandatory for all state PWD, NHAI and municipal road project acceptance.

MORTH Clause 404 Compliance

Complete grading and mechanical test suite per MORTH Clause 404 for WBM base course.

All Three WBM Gradings

Grading 1 (90–45mm), Grading 2 (63–45mm) and Grading 3 (53–22.4mm) all tested.

Aggregate Impact Value (AIV ≤40%)

Resistance to impact loading per IS 2386 Part 4 — MORTH maximum 40% for WBM.

Flakiness & Elongation Index

Both shape indices tested per IS 2386 Part 1 — MORTH maximum 15% each for WBM.

NABL Certified Reports

All test and calibration results are backed by traceable measurements and standardized procedures.

Screenings Grading

Fine screenings particle size distribution verified alongside coarse aggregate grading.

Test in Action

Water Bound Macadam (WBM) Testing — Site Images

Water Bound Macadam Base Course on Road Project

WBM Coarse Aggregate Grading Sieve Analysis

Aggregate Impact Value Test per IS 2386 Part 4

Test Procedure

How the Water Bound Macadam (WBM) Testing is Conducted

1

Sample Collection

Representative samples of coarse aggregate and screenings collected per IS 2386 Part 1 from stockpile or road layer. Minimum 50kg field sample reduced using riffle box.
2

Coarse Aggregate Grading

Dried sample passed through IS sieve series. Grading curve plotted against MORTH Clause 404 grading envelope for the specified WBM grade (1, 2 or 3).
3

Screenings Grading

Screenings sample sieved through smaller IS sieves. Grading checked against MORTH Table 400-5 requirements for the appropriate screening type.
4

Mechanical Tests — AIV, LAA, Shape

AIV and LA Abrasion per IS 2386 Part 4. Flakiness index and elongation index per IS 2386 Part 1. Specific gravity and water absorption per IS 2386 Part 3.
5

MORTH Compliance Report

All results compared against MORTH Clause 404 acceptance limits. NABL report with pass/fail compliance statement issued within 7 days.

Standards & Specifications

Applicable Test Standards

Standard	Title	Scope	Type
MORTH Clause 404	Specifications for Road and Bridge Works — Water Bound Macadam	WBM Specification	MORTH
IS 2386	Methods of Test for Aggregates for Concrete (Parts 1, 3, 4)	Aggregate Testing	Indian Standard
IRC 19	Standard Specifications and Code of Practice for Water Bound Macadam	WBM Standard	IRC
IS 2720 Part 28	Methods of Test for Soils — Determination of Dry Density by Sand Replacement	Field Density	Indian Standard

Applications

Where is the Water Bound Macadam (WBM) Testing Used?

State highway and district road WBM base course aggregate acceptance testing

Rural road construction (PMGSY) WBM material quality verification

Municipal road repair and resurfacing WBM aggregate source approval

Forest road and industrial access road WBM base layer testing

Quarry source approval testing for WBM aggregate suppliers

Historical road rehabilitation where WBM specification is retained

Why Choose Global Lab

Our Advantages

NABL Accredited ReportsLegally valid MORTH Clause 404 compliance certificates for PWD, NHAI and all road authorities.

All Three WBM GradingsGrading 1, 2 and 3 tested in our NABL-accredited laboratory — covers all WBM applications.

IRC 19 ExpertiseExperienced in WBM testing for state PWD, PMGSY and IRC specification projects.

Pan-India CoverageAggregate testing teams at all 7 NABL-accredited lab locations across India.

Fast 7-Day ReportComplete MORTH Clause 404 test suite reported within 7 days.

Combined Road PackageWBM + CRM + WMM + GSB testing offered as a complete road aggregate QC package.

Water Bound Macadam(IS 2386 / MORTH Clause 404)