Chemical Analysis of Soil(IS 2720 Parts 22, 26 & 27)
Chemical testing of soils for construction — pH, sulphate and chloride contents and organic matter per the IS 2720 method series — assessing aggressivity to concrete foundations and buried services.
What is Chemical Analysis of Soil?
Foundations sit in a chemical environment as much as a mechanical one. Sulphate-bearing soils attack buried concrete (IS 456 Table 4 grades the exposure), chlorides corrode buried steel and reinforcement, acidic soils dissolve cement matrix, and organic matter compromises stabilisation and fill performance. The IS 2720 series provides the methods: Part 27 (soluble sulphates), Part 26 (pH), Part 22 (organic matter), with chloride determination by the allied aqueous-extract chemistry.
Global Lab runs the aggressivity suite on investigation and fill samples, reports each parameter against the IS 456 exposure classification and fill-suitability criteria, and flags where sulphate-resisting cement or protective coatings are warranted — chemistry that changes foundation specifications before concrete is poured wrong.
How the Chemical Analysis of Soil is Conducted
- 1
Sampling & Preparation
Investigation or fill samples are air-dried, pulverised and split; aqueous extracts are prepared at the standard soil-water ratio. - 2
pH Determination
Soil pH is measured on the standard suspension per IS 2720 (Part 26). - 3
Sulphate Content
Total soluble sulphates are determined per IS 2720 (Part 27) and expressed for IS 456 exposure grading. - 4
Chloride Content
Chlorides in the aqueous extract are determined by argentometric titration. - 5
Organic Matter
Organic content is determined per IS 2720 (Part 22) for fill and stabilisation suitability. - 6
Reporting
The aggressivity suite with exposure classification and protection recommendations is issued via Autovity QLMS.
Applicable Test Standards
| Standard | Title | Scope | Type |
|---|---|---|---|
| IS 2720 (Pt 27):1977 | Methods of Test for Soils — Determination of Total Soluble Sulphates (Reaffirmed) | Sulphate Content | Indian Standard |
| IS 2720 (Pt 26):1987 | Methods of Test for Soils — Determination of pH Value (Reaffirmed) | pH | Indian Standard |
| IS 2720 (Pt 22):1972 | Methods of Test for Soils — Determination of Organic Matter (Reaffirmed) | Organic Content | Indian Standard |
| IS 456:2000 | Plain and Reinforced Concrete — Code of Practice (Table 4) | Sulphate Exposure Classes | Indian Standard |