Shrinkage reduced in high-performance concrete by internal curing using pre-soaked lightweight aggregate

Compared with normal strength concrete (NSC) test results on high-performance concrete (HPC) show, in general, lower long-term deformation behaviour. On the other hand the conditions of HPC (reduced w/c, use of silica fume and superplasticisers) have besides others also negative effects such as self-desiccation with shrinkage and cracking. Under controlled laboratory conditions long-term running tests ( https://www.w3.org/1998/Math/MathML" display="inline"> ≈ 900 days) were carried out with HPC, with those parts of the normal aggregates were substituted by lightweight aggregates (LWA). Whereas sealed specimens with normal aggregates (reference specimen) reached shrinkage deformation of https://www.w3.org/1998/Math/MathML" display="inline"> ε S , 700 d ≈ + 400 μ m / m , the specimen with LWA show a slowly increasing swelling with https://www.w3.org/1998/Math/MathML" display="inline"> ε q , 900 d ≈ - 200 μ m / m . Because the shrinkage measurements have been started only at the age of around 24 hours after mixing, the early age shrinkage is not included.