Chemical Analysis of Aggregate(IS 2386 Part 7 · IS 383:2016)
Chemical testing of coarse and fine aggregates — chlorides, sulphates, alkali-aggregate reactivity and deleterious constituents — against the IS 383:2016 acceptance limits.
What is Chemical Analysis of Aggregate?
Aggregate makes up three-quarters of concrete's volume — and its chemistry travels with it. Salt-contaminated sand imports chlorides, pyrite-bearing rock imports sulphates, and reactive silica triggers alkali-aggregate reaction (AAR) — the slow expansion that cracks dams and bridges decades after casting. IS 383:2016 (Coarse and Fine Aggregate for Concrete — Specification) sets the acceptance limits, with test chemistry drawn from IS 2386 (Part 7):1963 — Alkali Aggregate Reactivity and allied methods.
Global Lab tests chloride and sulphate contents, mortar-bar/chemical reactivity screening, organic impurities in sand, and the deleterious-materials suite — giving source-approval verdicts for natural, crushed and manufactured (M-sand) aggregates against the current 2016 specification, which formally recognised manufactured aggregates.
How the Chemical Analysis of Aggregate is Conducted
- 1
Sampling & Reduction
Aggregate samples are taken per IS 2430 practice and riffled down to analytical portions. - 2
Chloride & Sulphate Determination
Water-soluble chloride and sulphate contents are determined by titrimetric/gravimetric chemistry and expressed against IS 383 limits. - 3
Alkali-Aggregate Reactivity
Reactivity is screened per IS 2386 (Part 7) — chemical method and/or mortar-bar expansion as specified. - 4
Organic Impurities & Deleterious Materials
Colour-comparison organics test on sand and the deleterious-materials determinations (clay lumps, coal, mica etc.) are performed. - 5
Reporting
The chemical suite with per-parameter IS 383:2016 verdicts is issued via Autovity QLMS.
Applicable Test Standards
| Standard | Title | Scope | Type |
|---|---|---|---|
| IS 2386 (Pt 7):1963 | Methods of Test for Aggregates for Concrete — Alkali Aggregate Reactivity (Reaffirmed) | AAR Screening | Indian Standard |
| IS 383:2016 | Coarse and Fine Aggregate for Concrete — Specification (Third Revision) | Acceptance Limits | Indian Standard |
| IS 456:2000 | Plain and Reinforced Concrete — Code of Practice | Mix Chloride/Sulphate Context | Indian Standard |