Effect of drying conditions on autogenous shrinkage in ultra-high performance concrete at early-age

• Published in: Materials and structures Vol. 44; no. 5; pp. 879 - 899
• Main Authors: Soliman, A. M., Nehdi, M. L.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-06-2011; Springer Nature B.V
• Subjects: Admixtures; Building construction; Building Materials; Civil Engineering; Concretes; Curing; Drying; Engineering; Exposure; Machines; Manufacturing; Materials Science; Original Article; Processes; Relative humidity; Shrinkage; Solid Mechanics; Superabsorbent polymers; Theoretical and Applied Mechanics; Early-age; Autogenous; Shrinkage; Chemically bound water; Drying; Strain
• ISSN: 1359-5997; 1871-6873
• DOI: 10.1617/s11527-010-9670-0

This experimental study investigated the effects of drying conditions on the autogenous shrinkage of ultra-high performance concrete (UHPC) at early-ages. UHPC specimens were exposed to different temperatures, namely, 10, 20 and 40°C under a relative humidity (RH) ranging from 40 to 80%. The effects of using a shrinkage-reducing admixture (SRA) and a superabsorbent polymer (SAP) as shrinkage mitigation methods were also investigated. The results show that autogenous and drying shrinkage are dependent phenomena. Assuming the validity of the conventional superposition principle between drying and autogenous shrinkage led to overestimating the actual autogenous shrinkage under drying conditions; the level of overestimation increased with decreasing RH. Both SRA and SAP were very effective in reducing autogenous shrinkage under sealed conditions. However, SRA was efficient in reducing drying shrinkage under drying conditions, while SAP was found to increase drying shrinkage. Generally, results indicate that adequate curing is essential for reducing shrinkage in UHPC even when different shrinkage mitigation methods are applied.