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Article
Publication date: 13 August 2018

Jinliang Liu, Yanmin Jia, Guanhua Zhang and Jiawei Wang

In the freeze-thaw zone, the pre-stressed concrete of bridge structure will be damaged by freezing-thawing, the bearing capacity of structure will decrease and the safety…

Abstract

Purpose

In the freeze-thaw zone, the pre-stressed concrete of bridge structure will be damaged by freezing-thawing, the bearing capacity of structure will decrease and the safety will be affected. The purpose of this paper is to establish the time-dependent resistance degradation model of structure in the freeze-thaw zone, and analysis the structural reliability and remaining service life in different freeze-thaw zones.

Design/methodology/approach

First, according to the theory of structural design, a calculation model of the resistance of pre-stressed concrete structures in f freeze-thaw zone is established. Second, the time-dependent resistance model was verified by the test beam bending failure test results done by the research group, which has been in service for 20 years in freeze-thaw zone. Third, using JC algorithm in MATLAB to calculate the index on the reliability of pre-stressed concrete structure in frozen thawed zones, forecasting the s remaining service life of structure.

Findings

First, the calculation model of the resistance of pre-stressed concrete structures in freeze-thaw zone is accurate and it has excellent applicability. Second, the structural resistance deterioration time in Wet-Warm-Frozen Zone is the earliest. Third, once the pre-stressed reinforcement rusts, the structural reliability index will reach limit value quickly. Finally, the remaining service life of structure meets the designed expectation value only in a few of freeze-thaw zones in China.

Originality/value

The research will provide a reference for the design on the durability of a pre-stressed concrete structure in the freeze-thaw zone. In order to verify the security of pre-stressed concrete structures in the freeze-thaw zone, engineers can use the model presented in this paper for durability checking, it has an important significance.

Details

International Journal of Structural Integrity, vol. 9 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 26 June 2019

Wang Lijun and Li Qingbo

Asphalt mixture is widely used in road engineering, and its performance research is particularly important. But the study of asphalt mixture performance needs a lot of…

Abstract

Purpose

Asphalt mixture is widely used in road engineering, and its performance research is particularly important. But the study of asphalt mixture performance needs a lot of tests, such as bending test, splitting test and so on. It also needs a lot of time and material resources. The purpose of this paper is to obtain test results through finite element numerical simulation, and show that this saves a lot of manpower and material resources.

Design/methodology/approach

The mechanical parameters of the material are obtained through uniaxial compression tests. The true stress and plastic strain are calculated according to nominal stress and nominal strain. A constitutive model is established. Then a finite element model of asphalt mixture is established. The numerical simulation and performance study of asphalt mixture bending test is carried out. At the same time, according to the above method, the asphalt mixture is subjected to freeze-thaw cycles and ultraviolet aging, and the mechanical parameters are obtained by a uniaxial compression test. A numerical model is established to simulate the bending characteristics of asphalt mixture after freeze-thaw cycles and ultraviolet aging.

Findings

A uniaxial compression test of the asphalt mixture is conducted to obtain nominal stress and nominal strain. The true stress and plastic strain are calculated and the elastic modulus is established with Poisson’s ratio as the elastic part, and the true stress and plastic strain as the plastic part. The model is constructed, the finite element model is established and the bending test is numerically simulated. The verified trend is consistent, and the method is feasible. According to the above method, the concrete is subjected to freeze-thaw cycle and ultraviolet aging, and the finite element model is established by using uniaxial compression test to obtain parameters. The bending test is simulated and the verification method is feasible. With the increase of the number of freeze-thaw cycles and the increase of UV aging time, the maximum bending strain of SBS modified asphalt mixture and matrix asphalt mixture is decreased .The low-temperature performance of SBS modified asphalt mixture is better than that of matrix asphalt mixture.

Originality/value

A method of simulating asphalt mixture test by finite element method numerical simulation is established. By using this method, the performance of asphalt mixture is studied, which saves a lot of manpower and material resources. At the same time, this method can be used to study the characteristics of asphalt mixture under complex conditions.

Details

International Journal of Structural Integrity, vol. 10 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 18 May 2021

Ning Wang, Haitao Zhang and Huizhong Xiong

In order to unravel the evolution of microstructure characteristics and the change of mechanical properties of bituminous mixture in the freezing and thawing environment…

Abstract

Purpose

In order to unravel the evolution of microstructure characteristics and the change of mechanical properties of bituminous mixture in the freezing and thawing environment in cold region, this study starts from macroscopic experiments and analyzes the changes in mechanical properties of asphalt mixtures before and after freezing and thawing in detail. On this basis, the displacement of key particles in the structure of asphalt mixture under the action of external forces (before and after freezing and thawing) is simulated through the combination macroscopic and microscopic methods.

Design/methodology/approach

The climate in China exhibits high complexity and diversity, divided into five zones based on the temperature difference from south to north. Considering that the significant effect of geography and natural climate on the design, construction and maintenance of asphalt pavement, the criterion for the road construction at different areas should be highly different.

Findings

The results show that the mechanical properties of asphalt mixture greatly decrease due to the influence of freeze-thaw, and the displacement of key particles in the structure of asphalt mixture (several representative particle sizes were selected through experiments) is obviously observed because of the action of external force. By analyzing the variation of several key particle sizes after freezing-thawing cycle, the gradation standard of asphalt mixture aggregate suitable for cold area was obtained. The research results have certain theoretical and practical value for the design and application of asphalt mixture in cold area.

Originality/value

The results show that the mechanical properties of asphalt mixture greatly decrease due to the influence of freeze-thaw, and the displacement of key particles in the structure of asphalt mixture (several representative particle sizes were selected through experiments) is obviously observed because of the action of external force. By analyzing the variation of several key particle sizes after freezing-thawing cycle, the gradation standard of asphalt mixture aggregate suitable for cold area was obtained. The research results have certain theoretical and practical value for the design and application of asphalt mixture in cold area.

Details

Multidiscipline Modeling in Materials and Structures, vol. 17 no. 4
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 7 August 2019

H’mida Hamidane, Ayman Ababneh, Ali Messabhia and Yunping Xi

The purpose of this paper is to develop a method for predicting the chloride ingress into concrete structures, with an emphasis on the low temperature range where…

Abstract

Purpose

The purpose of this paper is to develop a method for predicting the chloride ingress into concrete structures, with an emphasis on the low temperature range where freeze-thaw cycles may cause damage.

Design/methodology/approach

The different phenomena that contribute to the rate and amount of transported chlorides into concrete, i.e., heat transfer, moisture transport and chloride diffusion are modeled using a two-dimensional nonlinear time dependent finite element method. In modeling the chloride transport, a modified version of Fick’s second law is used, in which processes of diffusion and convection due to water movement are taken into account. Besides, the effect of freeze-thaw cycles is directly incorporated in the governing equation and linked to temperature variation using a coupling term that is determined in this study. The proposed finite element model and its associated program are capable of handling pertinent material nonlinearities and variable boundary conditions that simulate real exposure situations.

Findings

The numerical performance of the model was examined through few examples to investigate its ability to simulate chloride penetration under freeze-thaw cycles and its sensitivity to factors controlling freeze-thaw damage. It was also proved that yearly temperature variation models to be used in service life assessment should take into account its cyclic nature to obtain realistic predictions.

Originality/value

The model proved promising and suitable for chloride penetration in cold climates.

Details

International Journal of Building Pathology and Adaptation, vol. 38 no. 1
Type: Research Article
ISSN: 2398-4708

Keywords

Article
Publication date: 13 November 2007

W.H. Wang, Q.W. Wang, H. Xiao and J.J. Morrell

To investigate the effects of moisture and freeze‐thaw cycling on the absorption and flexural properties of rice‐hull‐polyethylene (PE) composite.

Abstract

Purpose

To investigate the effects of moisture and freeze‐thaw cycling on the absorption and flexural properties of rice‐hull‐polyethylene (PE) composite.

Design/methodology/approach

Various rice‐hull‐PE composite specimens were submerged in water at various temperatures and subjected to various freeze‐thaw cycles. Various characterisations including water absorption, bending strength and stiffness, Fourier transform infrared spectroscopy and scanning electron microscope imaging were performed.

Findings

High temperatures accelerated the water sorption of the rice‐hull‐PE composite and increased the equilibrium moisture content. The uncoated surface was not significantly more easily permeated than the coated surface, contrary to expectations. However, more water was absorbed from the cut surface than from the original extruded surface. This was attributed to the tiny checks left on the surface by the sawing action, which indicated the importance of protecting the original surface layer from scraping or other damage. Bending strength and stiffness of the rice‐hull‐PE composite decreased significantly after the freeze‐thaw cycling treatment. The modulus of elasticity decreased more than the modulus of rupture. Compared to the effect of water immersion alone, freeze‐thaw cycling treatment slightly accelerated this decrease.

Research limitations/implications

The results of this study were obtained from accelerated laboratory experiments. Further research could be carried out to evaluate the properties of this rice‐hull‐PE composite in practical application.

Practical implications

The research revealed a possible degradation in quality when the rice‐hull‐PE composite is used in moist or freezing conditions. The resin layer on the extruded surface provides an important protection.

Originality/value

In China, rice‐hull powder is widely used as a reinforcing component in plastic composite. However, the durability of rice‐hull/PE composites has rarely been investigated. Results from this study will help users apply rice‐hull‐PE composites correctly and encourage the development of other agro‐fibre/polymer materials.

Details

Pigment & Resin Technology, vol. 36 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 11 October 2020

Mudasir Peerzada and Javed Ahmed Naqash

In cold areas, frost damage is the main factor for diminution of durability and serviceability of structures. Due to incessant freeze thaw regimes, micro cracks spread and…

Abstract

Purpose

In cold areas, frost damage is the main factor for diminution of durability and serviceability of structures. Due to incessant freeze thaw regimes, micro cracks spread and deteriorate concrete to point of failure.

Design/methodology/approach

The study aims to evaluate the fresh and hardened properties of concrete after thirty freeze-thaw cycles tailored with carbon nano tubes. For this purpose, samples with 0.4, 0.45, 0.48, 0.5 and 0.55 water cement ratio while 0.5 and 1% carbon nano tube (CNT) content by weight of cement were prepared.

Findings

At 0.48 water cement ratio and 0.5% CNT by weight of cement workability reduced by 37% and water absorption reduced by 0.04%. But compressive strength, split tensile strength and flexural strength increased by 15.38, 33.02 and 15.75%, respectively, after 30 freeze thaw cycles. Also, weight loss reduced with addition of 0.5% CNT by weight of cement after freeze thaw cycles.

Originality/value

Novelty of this research is to tailor traditional concrete with new materials.

Article
Publication date: 7 March 2016

Zhiming Ma, Tiejun Zhao, Jianzhuang Xiao and Ting Guan

Rebar corrosion in reinforced concrete is the major reason for the durability degradation, especially under harsh environment. This paper presents an experiment conducted…

Abstract

Purpose

Rebar corrosion in reinforced concrete is the major reason for the durability degradation, especially under harsh environment. This paper presents an experiment conducted to investigate the influence of freeze-thaw cycles on the rebar corrosion in reinforced concrete. The purpose of this paper is to provide fundamental information about rebar corrosion under frost environment and improvement measures.

Design/methodology/approach

The related elastic modulus and compressive strength of different concrete specimens were measured after different freeze-thaw cycles. The accelerated rebar corrosion test was carried out after different freeze-thaw cycles; additionally, the value of calomel half-cell potential was determined. The actual rebar corrosion appearance was checked to prove the accuracy of the results of calomel half-cell potential.

Findings

The results show that frost damage aggravates the rebar corrosion rate and degree under freeze-thaw environment; furthermore, the results become more obvious with the freeze-thaw cycles increasing. Mixing the air-entrained agent into fresh concrete to prepare air-entrained concrete, increasing the cover thickness and processing the surface of concrete with a waterproofing agent can significantly improve the resistance to rebar corrosion. From the actual appearance of rebar corrosion, the results of calomel half-cell potential can well reflect the actual rebar corrosion in reinforced concrete.

Originality/value

The durability of reinforced concrete is mainly determined on chloride penetration that brings about rebar corrosion in chloride environments. Furthermore, the degradation of concrete durability becomes more serious in the harsh environment. As the concrete exposure to the freeze-thaw cycles environment, the freeze-thaw cycles accelerate the concrete damage, and the penetration of chloride into the concrete becomes easier because of the growing pore and crack sizes. In addition, rebar corrosion caused by chloride is one of the major forms of environmental attack on reinforced concrete. The tests conducted in this paper will describe the rebar corrosion in reinforced concrete under freeze-thaw environment.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 8 November 2011

A.M. Forster and K. Carter

The selection of lime mortars for masonry structures can be an important component of a repair or new build project. This selection is considered difficult due to the…

1204

Abstract

Purpose

The selection of lime mortars for masonry structures can be an important component of a repair or new build project. This selection is considered difficult due to the number of variables to consider during the decision‐making process and the perceived inherent complexity of the materials. The purpose of this paper is to discuss the selection process for determining suitable natural hydraulic lime repair mortars for masonry.

Design/methodology/approach

The paper presents a conceptual and practical framework for the determination of suitable lime mortars for repair and construction of masonry structures, drawing and building on relevant, literature and existing best practice guidance on specification.

Findings

The use of various relatively newly produced data sets pertaining to durability can aid in the appropriate selection of lime mortars. These determinants must however, be correlated with traditional evaluation of exposure levels, building detailing and moisture handling performance. Building condition survey of the existing fabric is essential to enable refinement of the selection process of these mortars. The adjustment of the initially identified mortars highlighted in the best practice guide may potentially benefit from modification based on the aforementioned factors.

Originality/value

Whilst data exist to help the practitioner select hydraulic lime mortars they have never been correlated with the tacit and expressed protocols for survey and the evaluation of the performance of structures.

Details

Structural Survey, vol. 29 no. 5
Type: Research Article
ISSN: 0263-080X

Keywords

Article
Publication date: 15 November 2021

Wei Xiao, Enlong Liu, Xiao Yin, Guike Zhang, Chong Zhang and Qihao Yu

The purpose of this paper is to perform the thermo-hydro-mechanical (THM) numerical analysis in order to study the thawing process for frozen soil and to predict the…

83

Abstract

Purpose

The purpose of this paper is to perform the thermo-hydro-mechanical (THM) numerical analysis in order to study the thawing process for frozen soil and to predict the thawing settlement.

Design/methodology/approach

A new one-dimensional multi-field physical coupled model was proposed here to describe the thawing process of saturated frozen soil, whereby the void ratio varied linearly with effective stress (Eq. 10) and hydraulic conductivity (Eq. 27b). The thawing process was simulated with different initial and boundary conditions in an open system with temperature variations. The mechanical behavior and water migration of the representative cases were also investigated.

Findings

The comparisons of representative cases with experimental data demonstrated that the model predicts thawing settlement well. It was found that the larger temperature gradient, higher overburden pressure and higher water content could lead to larger thawing settlement. The temperature was observed that to distribute height linearly in both frozen zone and unfrozen zone of the sample. Water migration forced to a decrease in the water content of the unfrozen zone and an increase in water content at the thawing front.

Research limitations/implications

In this study, only the one-directional thawing processes along the frozen soil samples were investigated numerically and compared with test results, which can be extended to two-dimensional analysis of thawing process in frozen soil.

Originality/value

This study helps to understand the thawing process of frozen soil by coupled thermo-hydro-mechanical numerical simulation.

Details

Engineering Computations, vol. 39 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 6 April 2020

Annan Jiang, Shuai Zheng and Shanyong Wang

This paper aims at the problem of surrounding rock excavation damage zone of tunneling in the rich water region, this paper aims to propose a new seepage-stress-damage…

Abstract

Purpose

This paper aims at the problem of surrounding rock excavation damage zone of tunneling in the rich water region, this paper aims to propose a new seepage-stress-damage coupling model and studied the numerical algorithm. This reflects the characteristics of rock damage evolution, accompanied by plastic flow deformation and multi-field interaction.

Design/methodology/approach

First of all, rock elastoplastic damage constitutive model based on the Drucker–Prager criterion is established, the fully implicit return mapping algorithm is adopted to realize the numerical solution. Second, based on the relation between damage variation and permeability coefficient, the rock stress-seepage-damage model and multi-field coupling solving iterative method are presented. Finally, using the C++ language compiled the corresponding programs and simulated tunnel engineering in the rich water region.

Findings

Results show that difference evolution-based back analysis inversed damage parameters well, at the same time the established coupling model and calculating program have more advantages than general conventional methods. Multiple field coupling effects should be more considered for the design of tunnel support.

Originality/value

The proposed method provides an effective numerical simulation method for the construction of the tunnel and other geotechnical engineering involved underground water problems.

Details

Engineering Computations, vol. 37 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

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