Chemical Analysis of Concrete(IS 14959 · IS 4032 · IS 456 Limits)
Chemical testing of fresh and hardened concrete — chloride and sulphate content, cement content and pH — against the IS 456:2000 durability limits that decide reinforcement corrosion risk.
What is Chemical Analysis of Concrete?
Concrete fails chemically long before it fails structurally: chlorides depassivate reinforcement and drive corrosion, sulphates attack the cement matrix, and carbonation lowers the pH shield around steel. IS 456:2000 fixes hard limits — chloride content max 0.6 kg/m³ for reinforced concrete (0.4 for prestressed), sulphate limits on the mix — and chemical analysis is how compliance and forensic condition are established.
Global Lab determines acid-soluble chloride per IS 14959 (Part 2) on hardened concrete (Part 1 for fresh/aggregates context), sulphate content and cement content by the IS 4032 analytical route, and pH/carbonation depth — supporting durability audits, corrosion investigations and dispute resolution on structures of any age.
How the Chemical Analysis of Concrete is Conducted
- 1
Sampling
Cores, drilled powder at specified depths, or fresh-mix samples are collected with location and depth mapping. - 2
Sample Preparation
Hardened samples are crushed, pulverised and split to analytical size; depth increments kept separate for profiling. - 3
Chloride Determination
Acid-soluble chloride is determined per IS 14959 (Part 2) by titration and expressed as kg/m³ of concrete. - 4
Sulphate & Cement Content
Sulphate (as SO₃) and cement content are determined through the IS 4032 analytical scheme. - 5
pH & Carbonation
Sample pH and phenolphthalein carbonation depth are measured where corrosion assessment is the objective. - 6
Reporting
Results with IS 456 limit verdicts and depth profiles are issued via Autovity QLMS.
Applicable Test Standards
| Standard | Title | Scope | Type |
|---|---|---|---|
| IS 14959 (Pt 2):2001 | Determination of Water Soluble and Acid Soluble Chlorides in Mortar and Concrete — Hardened Mortar and Concrete (Reaffirmed) | Chloride Content | Indian Standard |
| IS 4032:1985 | Method of Chemical Analysis of Hydraulic Cement (Reaffirmed) | Sulphate / Cement Content | Indian Standard |
| IS 456:2000 | Plain and Reinforced Concrete — Code of Practice | Durability Limits | Indian Standard |