Penetration Test of Bitumen
(Bitumen Grade Classification)

Measurement of the consistency of bituminous materials by the depth of penetration of a standard needle under a defined load and time at 25°C — the primary method for bitumen grade classification.

Overview

What is the Penetration Test of Bitumen?

The Penetration Test measures the hardness or consistency of bitumen by measuring the depth (in tenths of a millimetre) to which a standard 100g needle penetrates a bitumen sample in 5 seconds at 25°C. Penetration value directly classifies bitumen grade — 30/40, 60/70, 80/100 etc. — with lower values indicating harder bitumen.

Conducted as per IS 1203 and ASTM D5, penetration testing is the most fundamental and widely used bitumen quality test. All paving bitumens are classified by penetration grade per IS 73, and penetration testing is mandatory for every tanker load of bitumen received at a hot mix plant.

Primary Grade Classification

Penetration value directly classifies bitumen as Grade 30/40, 60/70, 80/100 etc.

25°C Temperature Controlled Bath

Penetration bath maintained at 25±0.1°C per IS 1203 precision requirement.

Standard 100g Needle

NABL-calibrated penetrometer with standardised needle, weight and timer.

Triplicate Testing

Three penetration readings taken on same sample and averaged per IS 1203.

NABL Certified Reports

All results on NABL-accredited letterhead with IS 73 grade classification.

VG Grade Equivalent

Penetration result correlated to Viscosity Grade (VG 10/20/30/40) equivalents.

Test in Action

Penetration Test of Bitumen — Site Images

Penetrometer Needle on Bitumen Sample

5-Second Penetration Reading

IS 73 Grade Classification Chart

Test Procedure

How the Penetration Test of Bitumen is Conducted

1

Sample Preparation

Bitumen sample heated to minimum 60°C above softening point. Poured into tin container and cooled at room temperature for 1 hour, then 25°C bath for 1 hour.
2

Penetrometer Setup

Calibrated penetrometer with 100g total weight (needle + shaft + weight) adjusted to just touch bitumen surface.
3

5-Second Penetration

Needle released for exactly 5 seconds. Depth of penetration read in 0.1mm divisions.
4

Three Readings

Penetrometer repositioned at three equidistant points on the sample surface. Each reading taken after re-levelling.
5

Average & Classification

Average of 3 readings reported. Bitumen classified per IS 73 penetration grade table. NABL report within 3 days.

Standards & Specifications

Applicable Test Standards

Standard	Title	Scope	Type
IS 1203	Methods for Testing Tar and Bituminous Materials — Determination of Penetration	Penetration Test	Indian Standard
IS 73	Paving Bitumen — Specification	Bitumen Grades	Indian Standard
ASTM D5	Standard Test Method for Penetration of Bituminous Materials	Penetration	ASTM
MORTH	Specifications for Road and Bridge Works — Clause 500	Bitumen Spec	MORTH

Applications

Where is the CAPO Test Used?

Grade verification of every bitumen tanker delivery at hot mix plant

Acceptance testing of paving bitumen for NHAI and state highway projects

PMB and CRMB base bitumen penetration verification

Bitumen storage quality monitoring for extended stockpile periods

Forensic investigation of pavement failures attributed to incorrect bitumen grade

Research on bitumen aging and hardening during storage and mixing

Why Choose Global Lab

Our Advantages

NABL Accredited ReportsLegally valid IS 73 grade certificates for NHAI and MORTH compliance.

Precise Temperature Control25°C bath with ±0.1°C precision for reproducible, accurate results.

Complete Bitumen PackagePenetration + Ductility + Softening Point + Flash Point offered together.

Fast 3-Day TurnaroundGrade classification report within 3 working days.

Pan-India CoverageBitumen testing at all 7 lab locations for highway project QC.

Same-Day Results AvailableFor urgent site decisions, same-day results can be arranged.

Penetration Test of Bitumen(Bitumen Grade Classification)