# Portland Cement Soundness

When referring to portland cement, "soundness" refers to the ability of a hardened cement paste to retain its volume after setting without delayed destructive expansion (PCA, 1988).

- Canonical URL: https://pavementinteractive.org/reference-desk/testing/cement-tests/portland-cement-soundness/
- Last updated: 2026-11-01
- Review: reviewed by licensed professional engineers on the previous Pavement Interactive site, where reviewers were not recorded by name
- Standards: AASHTO T 107, ASTM C151

When referring to portland cement, "soundness" refers to the ability of a hardened [cement paste](https://pavementinteractive.org/glossary/cement-paste/) to retain its volume after setting without delayed destructive expansion (PCA, 1988[^1]). This destructive expansion is caused by excessive amounts of free lime (CaO) or magnesia (MgO). Most portland cement specifications limit magnesia content and expansion. The typical expansion test places a small sample of cement paste into an autoclave (a high pressure steam vessel). The autoclave is slowly brought to 2.03 MPa (295 psi) then kept at that pressure for 3 hours. The change in specimen length due to its time in the autoclave is measured and reported as a percentage. ASTM C 150, *Standard Specification for Portland Cement* specifies a maximum autoclave expansion of 0.80 percent for all portland cement types.

## Standard Test Methods

- AASHTO T 107 and ASTM C 151: Autoclave Expansion of Portland Cement

## Sources

[^1]: Portland Cement Association (PCA) (1988). Design and Control of Concrete Mixtures. Portland Cement Association. Skokie, IL.