Dimensional deformation of shale ceramsite based high‐strength lightweight aggregate concrete

Large shrinkage or expansion of lightweight aggregate concrete in buildings would induce potential cracking for structure, especially at high strength. This study explores the dimensional deformation of concrete with 0–50 vol% saturated shale ceramsite by volume. Workability, strength, and volume stability were experimentally investigated. Results indicate that the rough surface and porous structure of ceramsite significantly reduced the flowability of fresh concrete. Compressive and splitting tensile strength follow a non‐monotonic trend with an optimal ceramsite content of 20% due to enhanced interfacial transition zone. Early‐age expansion was found to increase with lightweight aggregate content because of aggregate floating and hydration products agglomeration. The shrinkage of high strength concrete was effectively mitigated by saturated ceramsite, indicating great internal curing ability of porous ceramsite. When the amount of ceramsite was over 30%, concrete exhibited net expansion even after 28 days' sealed curing. The saturation period was extended and the internal relative humidity was found to increase thereafter thanks to the moisture compensation for water consumption by hydration and drying.