Water Transport in Unsaturated Cracked Concrete under Pressure

Yuanzhu, Zhang; Zhang, Siming; Wei, Gang; Wei, Xinjiang; Jin, Liu; Xu, Kuixin

doi:10.1155/2019/4504892

Cited by 4 publications

(3 citation statements)

References 23 publications

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“…As shown in Table 1, concrete test blocks were fabricated according to the concrete mix design of the Shenjiamen Subsea Tunnel in Zhoushan, Zhejiang Province, China. To simulate two types of water seepage patterns, namely spot leakage and line leakage, two different types of test blocks were prepared following the methodology described in reference [27]. For the BI test block, a smooth ϕ6 reinforcement bar was embedded along the axis of the block to create prefabricated holes.…”

Section: Test Specimens Preparationmentioning

confidence: 99%

Prediction of Wet Area of Underwater Tunnel Lining

Lai,

Zhang,

2024

Buildings

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The issue of water seepage poses a significant challenge in tunnel infrastructure. Wet areas are commonly used to evaluate the degree of water seepage in tunnel projects. To investigate the feasibility for numerical simulation to predict a wet area, we selected concrete test blocks with two types of defects—holes and cracks—as the research specimens. Numerical models for various seepage conditions were constructed using TOUGH2, and the results were validated through laboratory experiments. Additionally, the Shenjiamen Subsea Tunnel was simplified into a numerical model, employing TOUGH2 to forecast its future wet area performance within the scope of national standards. The outcomes of our research revealed that point seepage and line seepage exhibited circular and elliptical morphologies, respectively. Moreover, external water pressure and defect size exerted a significant influence on the expansion of the wet area. Notably, the impact of crack width surpassed that of hole diameter. Encouragingly, the numerical models generated using TOUGH2 for unsaturated concrete demonstrated excellent agreement with laboratory test results concerning the geometry, size, and pattern of the wet area. These findings signified the potential of TOUGH2 numerical simulation as a valuable tool in predicting the lifespan of tunnels.

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Section: Test Specimens Preparationmentioning

confidence: 99%

Prediction of Wet Area of Underwater Tunnel Lining

Lai,

Zhang,

2024

Buildings

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“…The impact of cracking on concrete permeability has been extensively studied in the past decade [9][10][11][12][13]. However, the fluid flow process in the crack network is complex.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of nonlinear flow characteristics in cracked polypropylene fibre-reinforced concrete

Qin

et al. 2021

Mater Struct

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Seepage has always been a major problem in concrete-faced rockfill dam projects. Splitting cracks were made in the laboratory and water permeability tests were carried out on specimens with different crack widths (100-400 lm) to understand the influence of polypropylene fibre on the transporting characteristics of fluid through a single crack of concrete. The influence of polypropylene fibre content (0.6, 0.9, 1.2 and 1.5 kg/m 3 ) on crack tortuosity and roughness was evaluated. We conducted six water permeability tests for each sample with different hydraulic gradients using our self-designed test instrument. The results show that the incorporated fibres can improve the tortuosity and roughness of concrete cracks. The nonlinear relationship between pressure gradient and volumetric flow rate in cracked concrete penetration was shown based on Forchheimer's law. An empirical formula is proposed to quantify the relationship between the coefficients of the linear contribution to the Forchheimer equation and the ones of the nonlinear part. Besides, the studied critical Reynolds number shows a decreasing tend with the increase in hydraulic crack width, and the range is between 1 and 32.

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“…Water is the key factor of reducing the durability of concrete structures [ 7 ]. Concrete with microcracks and pores provides a way for the transport of corrosive substances in concrete, such as Cl − [ 8 ], CO 2 [ 9 , 10 ], sulfate [ 11 ], etc.…”

Section: Introductionmentioning

confidence: 99%

Polymer for Internal Hydrophobization of Cement-Based Materials: Design, Synthesis, and Properties

et al. 2021

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A series of novel comb-like poly(butyl acrylate)-g-poly(dimethylaminoethyl methacrylate) (PBA-g-PDMAEMA) with different side chain lengths were designed and successfully synthesized by the “first main chain then side chain” method. Infrared Spectroscopy (IR), 1H Nuclear Magnetic Resonance (1H NMR), and gel permeation chromatography (GPC) were used for structural confirmation and molecular weight characterization. This polymer exhibited responsive behavior from hydrophilicity to hydrophobicity under the alkaline environment of cement-based materials, with the contact angle of 105.6°, a decreased evaporation rate, and a hydrophile–lipophile balance (HLB) value. A significant internal hydrophobic effect on cement mortar was shown in the water absorption rate, which decreased by 75.2%, and a dry shrinkage-reducing rate of more than 30%. Furthermore, this polymer can effectively slow the exothermic rate, reduce the heat release, and delay the exothermic peak of cement hydration. It was interesting that these properties showed a direct correlation with the side chain length of the comb polymer. The aims of this study are to provide a new avenue to synthesize polymers with the spontaneous hydrophilicity–hydrophobicity transition in the cement system, achieving excellent internal hydrophobicity of cement-based materials, and to offer a promising alternative to resist external erosion for improving the durability and service life of cement-based materials.

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Water Transport in Unsaturated Cracked Concrete under Pressure

Cited by 4 publications

References 23 publications

Prediction of Wet Area of Underwater Tunnel Lining

Prediction of Wet Area of Underwater Tunnel Lining

Experimental investigation of nonlinear flow characteristics in cracked polypropylene fibre-reinforced concrete

Polymer for Internal Hydrophobization of Cement-Based Materials: Design, Synthesis, and Properties

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