Metakaolin Testing
(Calcined Kaolin — Pozzolanic SCM)

Complete physical and chemical testing of metakaolin as a supplementary cementitious material — verifying pozzolanic activity, fineness, chemical composition and strength activity index for high-performance concrete use.

Overview

What is the Metakaolin Testing?

Metakaolin is a highly reactive pozzolanic SCM produced by calcining kaolin clay at 650–800°C. With its platelet particle morphology and very high SiO₂ + Al₂O₃ content (typically >90%), metakaolin reacts rapidly with calcium hydroxide to form C-S-H and C-A-S-H gels — providing early strength gain, reduced permeability and improved sulphate resistance.

At Global Lab, metakaolin testing covers physical tests (Blaine fineness, specific gravity, moisture), pozzolanic activity index (Chapelle test and strength activity index), chemical analysis (SiO₂, Al₂O₃, Fe₂O₃, CaO, K₂O, SO₃) and particle size distribution by laser diffraction. Testing conducted per ASTM C618 Class N pozzolan requirements.

Chapelle Pozzolanic Activity

mg Ca(OH)₂ fixed per gram — direct measure of pozzolanic reactivity.

Strength Activity Index

7 & 28-day mortar strength vs OPC control per ASTM C618.

High Blaine Fineness

Typically 10,000–25,000 m²/kg — ultra-fine particle size confirmed.

SiO₂+Al₂O₃ Verification

Combined SiO₂+Al₂O₃+Fe₂O₃ ≥70% per ASTM C618 Class N.

NABL Certified Reports

All results on NABL-accredited letterhead per ASTM C618.

Particle Size Distribution

Laser diffraction D10, D50, D90 for complete particle size characterisation.

Test in Action

Metakaolin Testing — Site Images

Metakaolin Sample Preparation for Testing

Chapelle Pozzolanic Activity Test Setup

XRF Chemical Analysis of Metakaolin

Test Procedure

How the Metakaolin Testing is Conducted

1

Sample Collection

Metakaolin sample collected from bag or bulk delivery per ASTM C618 sampling procedure.
2

Physical Tests

Blaine fineness, specific gravity, moisture content, particle size distribution by laser diffraction.
3

Pozzolanic Activity

Chapelle test — mg Ca(OH)₂ consumed per gram. Strength activity index mortar cubes at 7 and 28 days.
4

Chemical Analysis

XRF for SiO₂, Al₂O₃, Fe₂O₃, CaO, MgO, SO₃, K₂O, Na₂O and loss on ignition at 950°C.
5

ASTM C618 Compliance Report

All results vs Class N pozzolan requirements. NABL report within 35 days.

Standards & Specifications

Applicable Test Standards

Standard	Title	Scope	Type
ASTM C618	Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete	Class N Pozzolan	ASTM
BS EN 197-1	Cement — Composition, Specifications and Conformity Criteria	Cement Standard	British Standard
IS 1727	Methods of Test for Pozzolanic Materials	Pozzolan Testing	Indian Standard
RILEM TC-CEA	Chemical Admixtures — Testing	Admixture Testing	RILEM

Applications

Where is the CAPO Test Used?

White architectural concrete and UHPC (ultra-high performance concrete)

Shotcrete and repair mortar requiring rapid early strength gain

Marine concrete with strict sulphate and chloride resistance requirements

High-rise building columns requiring high early-age strength

Precast ornamental elements requiring superior surface finish quality

Research on ternary blends (metakaolin + silica fume + OPC) for UHPC

Why Choose Global Lab

Our Advantages

NABL Accredited ReportsLegally valid ASTM C618 compliance certificates for metakaolin procurement.

Chapelle Test CapabilityDirect pozzolanic reactivity measurement — not just chemical composition.

Particle Size by Laser DiffractionD50 and full PSD curve for complete physical characterisation.

Mix Design IntegrationMetakaolin data fed directly into our HPC and UHPC mix design service.

Pan-India CoverageTesting across all 7 NABL-accredited lab locations.

Combined SCM PackageMetakaolin + Silica fume + Fly ash testing offered together.

Metakaolin Testing(Calcined Kaolin — Pozzolanic SCM)