Cracking in cement paste induced by autogenous shrinkage

Pietro Lura, Ole Mejlhede Jensen, Jason Weiss

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Detection and quantification of microcracks caused by restrained autogenous shrinkage in high-performance concrete is a difficult task. Available techniques either lack the required resolution or may produce additional cracks that are indistinguishable from the original ones. A recently developed technique allows identification of microcracks while avoiding artefacts induced by unwanted restraint, drying, or temperature variations during sample preparation. Small cylindrical samples of cement paste are cast with steel rods of different diameters in their centre. The rods restrain the autogenous shrinkage of the paste and may cause crack formation. The crack pattern is identified by impregnation with gallium and analyzed by optical and scanning electron microscopy. In this study, a non-linear numerical analysis of the samples was performed. Autogenous strain, elastic modulus, fracture energy, and creep as a function of hydration time were used as inputs in the analysis. The experimental results and the numerical analysis showed that samples with larger steel rods had the highest probability of developing microcracks. In addition, the pattern and the width of the observed microcracks showed good agreement with the simulation results.
Original languageEnglish
JournalMaterials and Structures
Volume42
Issue number8
Pages (from-to)1089-1099
ISSN1359-5997
DOIs
Publication statusPublished - 2009

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