Effect of electric field on water-film between concrete and formwork: Atomic-scale mechanisms and technology indicators

Y Yang and J Cao and YK Li and JH Yang and SJ Fu, CONSTRUCTION AND BUILDING MATERIALS, 498, 143979 (2025).

DOI: 10.1016/j.conbuildmat.2025.143979

Electric demolding method, as a novel construction technology, is extensively utilized in large-scale projects. However, its internal mechanism requires further exploration. This study focuses on the water- film between concrete and formwork to elucidate the effect of the electric field on the demolding process at the atomic-scale. Under combined horizontal and vertical electric fields, continuous water migrates towards the formwork side, along with ion migration that further accelerates the transport of water. Meanwhile, the deformation of water within confined space elevates the internal stress of the concrete cover. Analysis results indicate that electric field intensity (E) and electrified time (T) are crucial factors affecting demolding effect. Electric field intensity alters water structure by redistributing hydrogen bonds and exhibits a positive correlation with ion concentration, while the prolonged electrification time affects cementitious structure. Based on experiments, the mechanical model of concrete demolding under the electric field effect is established. It is recommended to maintain E = 0.02 V/m and approximately T = 30 min for optimal demolding effect. This study establishes a theoretical analysis system, and provides essential technical indicators for practical engineering applications, serving as guidance for electric demolding technology in large concrete structures.

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