The durability of shotcrete in cold region tunnel: A review

Hu, Zhao; Ding, Hui-Sheng; Lai, Jinxing; Wang, Hao; Wang, Xiuling; He, Siyue

doi:10.1016/j.conbuildmat.2018.07.088

Cited by 74 publications

(23 citation statements)

References 98 publications

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“…As shown in Figures 2 and 3, when the number of cycles is less than 300, the freeze-thaw damage in the FC and CF modes is more severe than the damage in the F mode, with the FC mode affecting the freeze-thaw damage to a greater extent than the CF mode. is is because in a freeze-thaw environment, the structure of concrete changes gradually from compact to porous and full of microcracks [36,37]. In a rapid carbonation environment, permeable CO 2 will interact with Ca(OH) 2 in concrete to cause a neutralisation reaction, through which acid salt CaCO 3 is generated to fill the internal structural pores and serve as grouting.…”

Section: Relative Dynamic Modulus Of Elasticitymentioning

confidence: 99%

Experimental Investigation of Neutralisation of Concrete with Fly Ash as Fine Aggregate in Freeze‐Thaw Environment

Zhang

Mao

Yang

et al. 2019

Advances in Civil Engineering

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To study the durability of concrete with fly ash as fine aggregate under alternate freeze-thaw and carbonation, freeze-thaw and carbonation cyclic tests are conducted to explore variation characteristics such as relative dynamic modulus of elasticity and neutralisation depth. The influence coefficient (λC) of carbonation on concrete freeze-thaw damage and the influence coefficient (λF) of freeze-thaw on concrete neutralisation are introduced. In addition, scanning electron microscopy is performed to reveal the deterioration mechanism of the alternating effect. Finally, through a regression analysis of test data, the mathematical expression of the composite damage coefficient kF under alternate freeze-thaw and carbonation is obtained. Based on these findings, a prediction model of the neutralisation depth of concrete is established with number of freeze-thaw cycles and water-cement ratio as parameters. The values calculated through this model and the values measured in the tests are highly correlated. This provides a theoretical reference and basis for the analysis of concrete durability in a multifactor environment.

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Section: Relative Dynamic Modulus Of Elasticitymentioning

confidence: 99%

Experimental Investigation of Neutralisation of Concrete with Fly Ash as Fine Aggregate in Freeze‐Thaw Environment

Zhang

Mao

Yang

et al. 2019

Advances in Civil Engineering

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“…Problems associated with frost damage, including lining leakage, spalling of lining, frost heave of the surrounding rock, and watering and freezing of the road surface, often render the tunnel unusable from August to September annually, significantly affecting the efficiency of the tunnel [6][7][8][9][10]. e typical engineering solution to tunnel frost damage in cold regions is laying a thermal insulation layer [11][12][13][14]. Numerous studies have been conducted on the influence of various factors on thermal insulation layer [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Thermal Conductivity Characteristics of Thermal Insulation Materials Immersed in Water for Cold‐Region Tunnels

Sun

Zhuang

et al. 2020

Advances in Materials Science and Engineering

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This study investigates the distribution of pore water on the basis of the measured mass moisture content after soaking the tunnel insulation material. This study also analyzes the influence of the distribution of pore water on the thermal conductivity of the material on the basis of this mass moisture content. Scanning images of phenolic and polyurethane insulation boards are obtained by computer tomography (CT). The gray volume moisture content (Gv) is deduced based on the CT scanning images, to determine the distribution of pore water (Gv is the ratio of the volume of the water sample (represented by the gray value) to the volume of the saturated water sample (represented by the gray value) which is the gray volume moisture content of the sample). The correlation between gray volume moisture content and mass moisture content is determined by comparing different algorithms of gray volume moisture content and volume moisture content. The relationship between mass moisture content and thermal conductivity can be determined using a self-made quasi-steady-state tester, whereas the relationship between gray volume moisture content and thermal conductivity can be derived indirectly. Related experimental research can predict the thermal conductivity of thermal insulation materials by using a new perspective and shows the influence of pore water distribution on the thermal conductivity of materials.

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“…Actually, sprayed concrete evolved from its homonymous mortar [8]. At present, sprayed concrete is mainly used for civil engineering applications such as tunnels [9], while sprayed mortar is basically used for fireproofing steel structures. However, it can also be used to reinforce unreinforced masonry (URM; Table A1 in Appendix A presents a complete list of abbreviations).…”

Section: Introductionmentioning

confidence: 99%

Bond Strength Tests under Pure Shear and Tension between Masonry and Sprayed Mortar

2020

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Sprayed mortar or shotcrete is a construction technology that could enhance existing masonry buildings’ resilience by reinforcing low-safety load-bearing walls. Many factors affect the resistance of shotcrete-reinforced structures. One of the most important is the bond strength at the interface between the shotcrete and the reinforced wall. According to previous technical literature, bond strength usually has two evaluation criteria: shear and tensile strength. The experimental campaign described in this article focused on the bond strength between sprayed mortar and three masonry materials without the influence of normal force or constraint, as well as the roughness of these materials. The analysis of these tests focused on determining the relation between bond strength, roughness, and material strength. The analyses revealed that material strength has a more significant effect on bond strength than roughness, and bond strength is related to shrinkage of the materials. On the basis of previous theories, these researchers found that when there is no obvious influence due to normal force and constraint, the shear strength and tensile strength are different, and the shear strength is likely to be the cohesion force of the two materials. Finally, this article concludes with a novel logarithmic relationship between these strengths.

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The durability of shotcrete in cold region tunnel: A review

Cited by 74 publications

References 98 publications

Experimental Investigation of Neutralisation of Concrete with Fly Ash as Fine Aggregate in Freeze‐Thaw Environment

Experimental Investigation of Neutralisation of Concrete with Fly Ash as Fine Aggregate in Freeze‐Thaw Environment

Thermal Conductivity Characteristics of Thermal Insulation Materials Immersed in Water for Cold‐Region Tunnels

Bond Strength Tests under Pure Shear and Tension between Masonry and Sprayed Mortar

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