Preperties of Linear Polyaspartic Polyurea Coated Concrete under NaCl Solution Immersion and Co-Action of Load and NaCl Solution Immersion

Abstract

In this paper both the NaCl immersion and the co-action of load and NaCl solution immersion were employed to analyze the wet adhesive property and resistance of chlorion diffusivity of two types of linear polyaspartic ester (PAE) polyureas coated concrete: B2（PAE-b-H12MDI prepolymerH66）coated concrete and F2（PAE-f-H12MDI prepolymerH62） coated concrete. The research on the adhesion of B2 and F2 coated concrete showed that the adhesion were about 2N/mm and 1.5N/mm respectively before exposure, and the adhesion reduced about 6.8% and 11.8% respectively after 10% NaCl immersion for 300 days and made 8% and 5% further decrease under the co-action of load and NaCl solution immersion, double-factor exposure for 300 days. Compared with single NaCl solution immersion, the co-action of load and NaCl solution immersion also had more influence on the chlorion diffusivity of the coated concrete. The average chlorion content of B2 and F2 coated concrete increased about 19-21%, and the diffusion coefficient of chlorion of B2 and F2 coated concrete was 10－13-10－14m2/s, due to the micro-crack of concrete in tensile area increased under bending load, accelerating chlorion diffusion and permeation. The research showed that chlorion diffusion behaviour of B2 and F2 coated concrete under the NaCl immersion and the co-action of load and NaCl solution immersion satisfied second Fick’s law.

Effect of rust inhibitors and surface strengthening materials on service life of marine RC structures

“…This reaction generates a corrosion-resistant C-S-H gel with a low calcium-silicon ratio, closes the micropores on the surface of concrete, and forms protection for the RC structure (Thompson et al, 1997). The C s of group PP is 0.021%, which is 95.1% lower than that of the blank group C. This is because the spray polyurea elastomer forms a compact, stable and corrosion-resistant physical protective layer on the concrete surface, effectively blocking chloride ion penetration (Lu et al, 2010). The C s of group XC is 0.394%, 8.2% lower than that of blank group C. This is because the active CaO, SiO 2 , etc., in the cement-based permeable crystalline waterproof material make use of the inherent chemical characteristics and porosity of concrete and permeate through water (Zhou et al, 2011).…”

“…Concrete preservatives and hydrophobic compound plugs have shown excellent RC structure protection effects and thus have become subjects of great interest (Liu et al, 2019). Among surface strengthening materials, silane forms hydrophobic barriers to block chloride ion intrusion, significantly reducing the free chloride ion diffusion coefficient (D) of the modified concrete layer (Christodoulou et al, 2013); water-based permeable crystalline waterproof materials block seawater and other harmful substances from invading the concrete by chemically reacting with the alkaline substances in the concrete to seal the fine pores in the surface layer (Song et al, 2016); organic protective coatings provide stable, reliable and longterm protection to RC structure by forming physical protective layers with high strength, elongation and wear resistance (Lu et al, 2010). By using the inherent chemical characteristics and porosity of concrete, active CaO, SiO 2 and other compounds in cement-based permeable crystalline materials (Pei et al, 2015;Pei et al, 2017;Li et al, 2019) transport and catalyze the hydration of particles in the concrete through water infiltration to form insoluble dendrite crystals that become integrated with the concrete, thus blocking the transport of seawater and other harmful substances.…”

Study on the Aging Properties of a Viscoelastic Protective Material for Concrete

“…Wei Wang et al evaluated the aging property of the silicone material by the test of water absorption after 1000h xenon lamp aging and the result showed the material has excellent anti-aging performance. Ping Lu et al conducted a series of accelerated aging tests on polyaspartic ester based polyurea and the results show that the resistance of this coating to salt-spray and dry-wet circulation was excellent, but the resistance to corrosion decreased under the co-action of UV and salt-spray (Lu, Huang, Shi and Zhu, 2010;Lu, Chen, and Huang, 2007).…”