Research on the toughening mechanism of modified nano-silica and silane molecular cages in the multi-scale microfracture of cement-epoxy composite

Pang, Bo; Yang, Jia; Pang, Sze Dai; Zhang, Yunsheng; Du, Hongjian; Geng, Guoqing; Ni, Henmei; Qian, Jiajia; Huang, Qiao; Yang, Lin; Liu, Guojian; Yang, Yonggan

doi:10.1016/j.cemconcomp.2021.104027

Cited by 19 publications

(4 citation statements)

References 32 publications

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“…The interactions between the PAM molecules and the C-S-H substrate are richer in form and stronger in intensity [57]. Regarding the interaction between PAC molecules and the C-S-H substrate, as shown in Figure 19a, similar to those between HPMC molecules and the C-S-H substrate, the mutual interaction between PAC molecules and the C-S-H substrate is also dominated by hydrogen bonding [56]. The ionic bonding range of Ca-O also far exceeded its theoretical range, indicating that there are similar indirect interactions between them.…”

Section: Local Structure Analysismentioning

confidence: 90%

Comparative Study of the Performance of Underwater Concrete between Anionic and Nonionic Anti-Washout Admixtures

Song,

Zheng,

et al. 2024

Buildings

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An investigation was carried out to study the influence of two types of anti-washout admixtures (AWAs) on the performance of underwater concrete, specifically, workability and washout resistance. The tested AWAs were hydroxypropyl methylcellulose (HPMC) and polyacrylamide (PAM) as nonionic AWAs and carboxymethyl starch (CMS) and polyanionic cellulose (PAC) as anionic AWAs. Rheological properties (slump and slump flow), washout resistance, and compressive strength were measured to evaluate the properties of the fresh and hardened concrete. The results indicate that anionic AWAs are more effective at improving workability and strength than nonionic AWAs in anti-washout underwater concrete. When the nonionic AWA dosage exceeded 0.3% (W/C = 0.45), the fluidity and air content were negatively impacted. Additionally, nonionic AWAs more readily alter the morphological structure of cement paste, affecting cement particle hydration and underwater concrete properties. Regarding the mechanical properties, compared with those of concrete without AWAs and with nonionic AWAs, the 28-day compressive strength of concrete with anionic AWAs reached 37 MPa, an increase of 151% and 131%, respectively. Compared with nonionic AWAs, concrete with anionic AWAs is more stable.

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Section: Local Structure Analysismentioning

confidence: 90%

Comparative Study of the Performance of Underwater Concrete between Anionic and Nonionic Anti-Washout Admixtures

Song,

Zheng,

et al. 2024

Buildings

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“…As the condition of bridges continues to deteriorate, more bridges will need repair each year. − In China, the problem of aging concrete structures is also very serious. It is estimated that in 2010, the maintenance cost of bridges alone in China amounted to 360–540 billion RMB. − Coating protection is an important means of improving concrete’s durability, ensuring that concrete structures can reach their service age, and reducing maintenance costs. , Concrete deterioration problems are closely related to water transport. , Hydrophobic impregnation is a common method of improving the durability of concrete by increasing the hydrophobicity of the concrete surface. It protects the concrete by reducing the damage caused by aggressive ions carried by water. − Silane and siloxanes all contain an alkyl group and several alkoxy groups.…”

Section: Introductionmentioning

confidence: 99%

Composite Hydrophobic Coatings with Progressive High Penetration through Chromatography: Protective Properties and Mechanisms

Pang,

Liu,

Wang

et al. 2024

ACS Appl. Polym. Mater.

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Hydrophobic treatment is one of the common measures to improve the durability of concrete. It enhances the durability of the concrete by establishing a hydrophobic barrier. However, the hydrophobic treatments commonly found in the market have a limited impact on the pore structure of the concrete surface. As a result, the concrete remains vulnerable to erosion caused by carbon dioxide and gaseous water. This paper presents a compound silane treatment agent that ensures good water repellency and improves the pore structure of the concrete surface. It has advantages over silane monomers in resisting water vapor and carbon dioxide migration. The pore refining mechanism of the compound silane was investigated using XRD and TG test methods. According to the results of the FTIR analysis, the compound silane penetrated the concrete in the form of a gradient. Compound silane can both repel water and refine pores. They are useful for addressing mold and peeling that result from water vapor on the surface layer.

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“…Concrete, as a widely used building material in modern construction, has been applied in various fields of building structures and infrastructures. When concrete structures are exposed to harsh environments such as coastal areas and saline soils, their surfaces can be damaged by freeze–thaw cycles [ 1 ], wetting–drying cycles [ 2 ], atmospheric carbonation [ 3 , 4 ], and ion corrosion [ 5 ], severely affecting the safety and durability of concrete structures [ 6 , 7 , 8 ]. The application of protective coatings to concrete surfaces is widely employed as a common method to prolong the lifespan of buildings and preserve the structural integrity of constructions within current engineering practices [ 9 , 10 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

“…Geopolymer materials are a novel type of inorganic binder prepared through an alkali–silica/alumina reaction and are characterized by chemical resistance, strong adhesion, and environmental friendliness [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], making them highly applicable in the formulation of protective coatings for concrete surfaces. In recent decades, extensive research has been conducted on the practical application of geopolymer coatings [ 7 , 22 , 23 , 24 , 25 , 26 ], with sagging identified as one of the significant issues encountered in current applications. Sagging not only compromises the aesthetic appeal of coatings but also undermines their protective capabilities.…”

Section: Introductionmentioning

confidence: 99%

Improving Sag Resistance in Geopolymer Coatings Using Diatomite Filler: Effects on Rheological Properties and Early Hydration

Hu,

Jin,

Pang

et al. 2024

Materials

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The reduction in the rheological parameters and dissolution rate of precursors in geopolymer coatings during early hydration significantly contributes to sagging. This study aims to improve the sag resistance of these coatings by incorporating diatomite filler. Rheological testing was conducted to assess the impact of diatomite and its concentration on the yield stress, plastic viscosity, and thixotropy of the geopolymer coatings. The results indicated that diatomite’s large specific surface area and high reactivity have a significant influence on the rheological parameters and early dissolution rate of precursors. With a diatomite concentration of 1.1%, the coating exhibited a yield stress of 2.749 Pa and a plastic viscosity of 0.921 Pa·s, maintaining stability, homogeneity, and no sagging at a thickness of 600 μm. Furthermore, the highly active SiO2 in diatomite participates in the secondary hydration reaction of the geopolymer materials led to the formation of substantial C-(A)-S-H gel. This gel enhances internal interconnectivity within the coating, thereby improving its rheological and mechanical properties.

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Research on the toughening mechanism of modified nano-silica and silane molecular cages in the multi-scale microfracture of cement-epoxy composite

Cited by 19 publications

References 32 publications

Comparative Study of the Performance of Underwater Concrete between Anionic and Nonionic Anti-Washout Admixtures

Comparative Study of the Performance of Underwater Concrete between Anionic and Nonionic Anti-Washout Admixtures

Composite Hydrophobic Coatings with Progressive High Penetration through Chromatography: Protective Properties and Mechanisms

Improving Sag Resistance in Geopolymer Coatings Using Diatomite Filler: Effects on Rheological Properties and Early Hydration

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