Thermal dilation and internal relative humidity of hardened cement paste

Zachary C. Grasley, David A. Lange

Research output: Contribution to journalArticlepeer-review


The coefficient of thermal dilation (CTD) of hardened cement paste and concrete is a function of the state of internal moisture in the pore system. It has been theorized that changes in the pore fluid pressure induced by temperature change causes additional dilation when the material is partially saturated. Drying shrinkage stresses in early-age concrete also evolve from changes in the pore fluid pressure. The Kelvin-Laplace equation relates changes in the pore fluid pressure to the measured internal relative humidity (RH). This research investigated the role of pore pressure changes on the CTD through internal RH measurements. A maximum change in humidity (ΔRH) due to temperature change (ΔT) was measured when the initial humidity was at an intermediate value. Likewise, the maximum CTD was also measured at an intermediate initial RH. Based on these findings, the additional thermal strain caused by changes in pore fluid pressure was modelled using internal RH measurements as a primary parameter.

Original languageEnglish (US)
Pages (from-to)311-317
Number of pages7
JournalMaterials and Structures/Materiaux et Constructions
Issue number3
StatePublished - Apr 2007

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)
  • Mechanics of Materials


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