Doubling the coating-substrate pull-off strength by growth of CaCO3 nano-crystals

•The coating-substrate pull-off strength increased by up to 112.2% with carbonation curing.•Interfacial debonding was altered to substrate failure after ACC treatment.•Pure physical adhesion had limited contribution to the strength rises.•Pillar-like CaCO3 nano-crystals provided the crystals anchori...

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Bibliographic Details
Published in:Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-10, Vol.474, p.145763, Article 145763
Main Authors: Dai, Yuqing, Lan, Yan, Wen, Rongjia, Xu, Chengji, Al-Mansour, Ahmed, Zhang, Zhidong, Li, Le, Zeng, Qiang, Li, Kefei
Format: Article
Language:English
Subjects:
CaCO3 crystals
Carbonation
Crystals anchoring
Interface
Mechanism
Pull-off strength
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Summary:•The coating-substrate pull-off strength increased by up to 112.2% with carbonation curing.•Interfacial debonding was altered to substrate failure after ACC treatment.•Pure physical adhesion had limited contribution to the strength rises.•Pillar-like CaCO3 nano-crystals provided the crystals anchoring adhesion. Strong coating-substrate adhesion is crucial for ensuring long-term durability and performance of protective coatings in various applications. The growth of nano crystals on the substrate may be a preferable way to enhance the coating-substrate interactions. Here, an accelerated carbonation curing (ACC) scheme (0.5 MPa CO2 gas pressure) was designed to grow calcium carbonate (CaCO3) nano-crystals on a mortar substrate at early age before coated with a waterborne epoxy resin (WER). Microstructures of the ACC-treated mortar specimens and the coating-substrate interfaces were characterized by multiple microscopic tests, and the compressive strength of the carbonated substrate and the pull-off coating-substrate strength were measured. Results showed that the ACC treatment not only increased the mortar strength (by up to 17%), but also greatly improved the pull-off strength (by up to 112.2%). Substrate failure took place in the mortars after the ACC treatment. The mechanisms of physical adhesion, surface roughness, and crystals anchoring caused by the growth of pillar-like CaCO3 nano-crystals may account for the largely raised pull-off strength. The findings would deepen the understandings of interfacial adhesion mechanisms between polymer coatings and cement-based substrates and provide new insights into developing stronger coating-substrate adhesions.
ISSN:1385-8947
1873-3212
DOI:10.1016/j.cej.2023.145763