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Effect Mechanism of Ice Crystals on Mechanical Properties of Shale Ceramsite Concrete

Journal of engineering Science and Technology Review 2021年第2期14卷 177-183页

作者： Wang, Qinting Qiu, Yuhang Zhao, Jianqing Yang, Jianhui Liu, Dejun International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention Henan Polytechnic University Jiaozuo454003 China Henan Province Engineering Laboratory for Eco-architecture and the Built Environment Henan Polytechnic University Jiaozuo454000 China School of Civil Engineering and Architecture Jiaxing University Jiaxing314001 China

To investigate the mechanism responsible for the embrittlement of concretes containing lightweight aggregates at cryogenic temperatures, a series of experiments were performed on all-lightweight shale ceramsite concrete (ALWSCC) and icicles at temperatures from -5 to -15 °C. The mechanical properties of ALWSCC specimens at cryogenic temperatures were analysed, the dependence of cryogenic mechanical properties on ice crystal volume and freezing temperature was also investigated. The Hansen model was used to invert the elastic modulus of ice crystals by a step-bystep approach. Results show that the compressive strength of ALWSCC specimens increases with the increasing volume fraction of ice crystals, and the strengthening effect gradually decreases after the ice crystal volume fraction exceeds 16.5%. The cubic compressive strength of ALWSCC specimens with ice crystals is more sensitive to freezing temperatures than that of dried ALWSCC specimens. Shear failure occurs when icicles are compressed, and the density and strength of ice increase with decreasing temperature below the freezing point. The elastic modulus of ice crystals is much higher than that of icicles at the same temperature, showing a huge size effect, and the ratio of the elastic modulus is less affected by temperature. The conclusions obtained in this study are important for understanding the mechanism of variation in the material properties of lightweight aggregate concrete in regions that experience cryogenic temperatures © 2021,Journal of engineering Science and Technology Review. All rights reserved

关键词： Elastic moduli

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The Face-Sharing Double Cages of Hydrate-Based CO2 Capture with the Presence of Cyclopentane:An Ab Initio Study

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SSRN 2024年

作者： Zhao, Weilong Wang, Chen Jia, Xuechen Yuan, Pengfei Zhang, Yongsheng Henan Province Engineering Laboratory for Eco-architecture and the Built Environment Henan Polytechnic University Jiaozuo454000 China Ministry of Education of China Chongqing University Chongqing400044 China

Hydrate-based CO2 separation and capture is an important technology to achieve carbon dioxide emission reduction. Nevertheless, the face-sharing double cages formation mechanism of gas hydrate remains largely unclear yet. This study investigates the face-sharing double cage formation process in the case of nucleation as well as the sⅡ hydrate growth-related pathway through ab initio computing. As a result, those clathrate cages gradually appear in sequence, with the 512 cage showing thermodynamic feasibility at early nucleation. Because of the heterogeneous hydrophobic-hydrophilic responses, in 512 and 51264 cages, water faces grow in the layer-separating and ring-expanding manners. The water-water, water-carbon dioxide and water-cyclopentane interactions play a predominant role in the formation of the cages, whereas carbon dioxide-cyclopentane interactions make little difference to the formation process. © 2024, The Authors. All rights reserved.

关键词： Carbon dioxide

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Comparison of Bond Properties between ALWSCC and Steel Bars Based on Different Test Methods 6

Comparison of Bond Properties between ALWSCC and Steel Bars ...

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6th International Technical Conference on Frontiers of Hydraulic and Civil engineering Technology, HCET 2021

作者： Yang, Jianhui Zhi, Wenchao Tang, Xujun Wang, Qinting Cosgrove, Tom Henan Province Engineering Laboratory for Eco-architecture and the Built Environment Henan Polytechnic University Jiaozuo454000 China Civil Engineering Department of Civil Engineering and Materials Science University of Limerick Dublin Ireland

ISBN: (纸本)9781643682341

Reasonable evaluation of the bond performance between steel bars and concrete has important theoretical and practical value for reinforced concrete structural design and seismic analysis. The stress (τ)-strain (ϵ) formula is corrected based on a pull-out test, and the load (F)-deflection (w) curves are analyzed according to the change of stiffness before and after crack appearance based on a beam test, and new estimation formulas are given. At the same time, the bond properties are compared between all-lightweight shale ceramsite concrete (ALWSCC) and normal weight concrete (NWC). The results show that the bond property of ALWSCC is better than NWC. The bond stresses of pull-out specimens and beam specimens are the same or similar under equal conditions, but the ultimate load (F0) of the former is about 3.66 times that of the latter, the peak slip (S0) of the latter is 4.80 times that of the former, and the latter has significant splitting or pull-out failure characteristics. The peak slip (S0) in this paper is larger than that in the related literature, where the pull-out specimens are no more than 10 mm, and are generally less than 2 mm, while the beam specimens are not more than 3 mm, with the others generally around 1 mm. The research results have reference values and guiding significance for similar experimental research and engineering practice. © 2021 The authors and IOS Press.

关键词： Reinforced concrete

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Numerical Study on the Separation of Carbon-Copper Mixed Particles in Single Fluidized Bed

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SSRN 2024年

作者： Zhang, Yongsheng Yuan, Pengfei Wang, Chen Jia, Xuechen Pan, Wenyan Zhao, Weilong School of Civil Engineering Henan Polytechnic University Jiaozuo454003 China School of Civil Engineering Henan Polytechnic University Jiaozuo454003 China Henan Province Engineering Laboratory for Eco-architecture and the Built Environment Henan Polytechnic University Jiaozuo454003 China Ministry of Education of China Chongqing University Chongqing400044 China

This study aims to separate mixed particles of carbon and copper in waste battery recycling by presenting a three-dimensional numerical simulation of gas-solid flow in a fluidized bed. The flow field, separation efficiency and trajectories of the particles were obtained using the turbulence model and the discrete phase model (DPM). The impact of changing the gas inlet velocity (from 0.5 m/s to 8 m/s) on the velocity distribution and particle separation in fluidized beds was also examined by the researchers. The outcomes demonstrate that the two distinct structures' vortex flow fields differ and that the separation efficiency is decreased by the mixed particles' rotation in the vortex. As the intake velocity rose between 4 and 8 m/s, the separation efficiency also increased noticeably. The theory calculations and the simulation findings are essentially in agreement. © 2024, The Authors. All rights reserved.

关键词： Vortex flow

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Influence Of Concrete Matrix Properties and the Unbonded Ratio of Rebar On The Flexural Performance of Rc Beams

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SSRN 2023年

作者： Yang, Jianhui Wang, Li Yang, Dongbo Wang, Qinting Henan Province Engineering Laboratory for Eco-Architecture and the Built Environment Henan Polytechnic University Jiaozuo454000 China Department of Mechanic Aerospace and Civil Engineering The University of Manchester ManchesterM15 4RB United Kingdom

Hybrid aggregates (normal-weight and lightweight aggregates) can effectively improve the physical and mechanical properties of concrete;however, the main aspects of the influence of hybrid aggregate concrete on the flexural performance of reinforced concrete (RC) beams have yet to be known. By taking strength-grade LC30 of all-lightweight concrete, LC40 of gravel lightweight concrete, hybrid aggregate lightweight concrete and hybrid aggregate concrete with less ceramsite for a concrete matrix, RC ordinary beams and bond–slip beams with specifications of 150 mm × 300 mm × 2400 mm were designed and produced. The influence of the concrete matrix and the unbonded ratio and reinforcement ratio of the bottom longitudinal rebar on the flexural performance of the two types of beams was analysed by a four-point bending test, and the load–deflection and load–slip curves were numerically simulated using the finite element method. Results showed that the hybrid aggregates can effectively adjust the dry apparent density, strength and elastic modulus of concrete to meet the design requirements. Although the physical and mechanical properties of the two types of beams are mainly controlled by the reinforcement ratio and unbonded ratio and the concrete matrix with different properties has minimal effect on them, it has great influence on the stiffness of the beam and the relative slip between the rebar and concrete matrix. Both types of beams conform to the plane section assumption and show that when the bottom longitudinal reinforcement ratio is 1%, the cooperative working performance of the rebar and concrete matrix is the best but decreases with the increase in unbonded ratio. The failure process of the two types of beams can also be divided into three stages: elastic stage, crack development stage and compressive failure stage. The crack propagation process, load–deflection curve and load–slip curve of the two types of beams are also similar, but they vary due to the concrete m

关键词： Reinforced concrete

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Effects of Aggregate Types and Softening Effect on Multiaxial Mechanics Properties of Lightweight Aggregate Concrete

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SSRN 2022年

作者： Yang, Jianhui Yuan, Dongdong Huang, Dainwu Wang, Qinting Henan Province Engineering Research Center of Eco-architecture and the Built Environment Henan Polytechnic University Jiaozuo454000 China School of Architecture Engineering Jiaxing University Jiaxing314001 China

Softening effect of lightweight aggregate (LWA) and concrete after a period of hydrostatic immersion on multiaxial mechanical properties of LWA concrete (LWAC), porosity of shale ceramsite (SC) and shale pottery (SP) and softening coefficient of SC were firstly tested and analysed to investigate the effect of aggregate types. LC30 all-lightweight SC concrete (ALWSCC, also known as all-lightweight concrete, ALWC) is then used as the benchmark. SC and SP were replaced with limestone gravel (LSG) and river sand (RS), respectively, in a single or simultaneous way using the same volume fraction. gravel lightweight concrete (GLWC), sand lightweight concrete (SLWC) and hybrid aggregate lightweight concrete (HALWC) were formed in turn, and ALWC, SLWC, GLWC and HALWC are collectively known as LWACs. The four kinds of LWACs were casted into corresponding specification and size specimens and demoulded after indoor curing for 24 hours (h), with their target ages (7–180 days [d]) maintained using standard and hydrostatic curing. Tests for strength and initial elastic modulus under uniaxial stress, ultimate compression strength and stress–strain curves under triaxial stress were carried out to analyse the influence of aggregate types and curing methods on mechanical properties and softening effect of LWACs. Results showed that all kinds of mechanical properties decreased after 180 d of hydrostatic curing (experimental age of conventional triaxial compression test is 90 d later). ALWC demonstrated the most evident decrease, followed by SLWC, HALWC and GLWC, thereby indicating that normal aggregates can significantly improve the softening effect of LWACs. Failure modes of triaxial compression specimens changed from splitting failure to shear failure, plastic platform phenomenon on stress–strain curves appeared and their descending section was gentler than that of the uniaxial compression test with the increase of confining pressure. Although relationships between ultimate compressi

关键词： Gravel

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Earth-Abundant Catalyst for Modification of Wheat Straw to Enhance Ammonia Mitigation from Fertilised Alkaline Soil

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SSRN 2024年

作者： Zhu, Zeyu Liu, Wei Zhao, Kexin Niu, Bo Brau, Lambert Li, Chaoyu Han, Bing College of Chemistry and Materials Science Key Laboratory of Analytical Science and Technology of Hebei Province Hebei University Baoding071002 China Key Laboratory for Farmland Eco-environment of Hebei Province Hebei Collaborative Innovation Centre for Green and Efficient Vegetable Industry College of Resources and Environmental Science Hebei Agricultural University Baoding071000 China Faculty of Science Engineering and Built Environment Deakin University BurwoodVIC3125 Australia Australian Centre for Water and Environmental Biotechnology Faculty of Engineering Architecture and Information Technology The University of Queensland St LuciaQLD4072 Australia School of Engineering Deakin University GeelongVIC3216 Australia

In this study, inexpensive earth-abundant catalyst of Co/TiO2 is coupled with a low-temperature modification approach to enhance NH3 adsorption capacity on wheat straw (WS). The highest NH3 uptake achieved is 111.9 mg/g, with 80.8% retention even after 3 hours of desorption. Mechanistic investigation indicates that the enhanced adsorption capacity stems from Co/TiO2, which facilitates generation of reactive oxygen species, leading improved ultra-micropore structure that enhances the interaction between NH3 and oxygen-containing functional groups through a trapping effect. The robust stability of adsorbed NH3 is attributed to the formation of amides or amines. Incorporation of only 1 wt.% WS-Co to urea-fertilised alkaline soil reduced NH3 volatilization by 83.1%. The significant effect is primarily attributed to the excellent adsorption capacity of WS-Co, rather than alterations in the relative abundance of the microbial community. These findings present a novel approach for development of effective fertilizer additive to mitigate NH3 volatilization from alkaline soil. © 2024, The Authors. All rights reserved.

关键词： Temperature

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Earth-Abundant Catalyst for Modification of Wheat Straw to Enhance Ammonia Mitigation from Fertilised Alkaline Soil

SSRN

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SSRN 2024年

作者： Zhu, Zeyu Niu, Bo Brau, Lambert Li, Chaoyu Han, Bing College of Chemistry and Materials Science Key Laboratory of Analytical Science and Technology of Hebei Province Hebei University Baoding071002 China Key Laboratory for Farmland Eco-environment of Hebei Province Hebei Collaborative Innovation Centre for Green and Efficient Vegetable Industry College of Resources and Environmental Science Hebei Agricultural University Baoding071000 China Faculty of Science Engineering and Built Environment Deakin University BurwoodVIC3125 Australia Australian Centre for Water and Environmental Biotechnology Faculty of Engineering Architecture and Information Technology The University of Queensland St LuciaQLD4072 Australia School of Engineering Deakin University GeelongVIC3216 Australia

关键词： Temperature

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Manufacturingtechnology andmechanical properties of modified recycled aggregate concrete

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Academic Journal of Manufacturing engineering 2019年第3期17卷 101-107页

作者： Wang, Yonggui Niu, Haicheng Fan, Yuhui School of Civil Engineering Henan Polytechnic University 2001 Century Road Jiaozuo454000 China Henan Province Engineering Laboratory for Eco-architecture and the Built Environment 2001 Century Road Jiaozuo454000 China

Wastes seriously affect people's living environment, such as concrete generated during the demolition of buildings. Waste concrete is usually treated as road filler by simple crushing. The usage is too simple, which is not conducive to saving resources. In this paper, the preparation process of recycled concrete modified by basalt fiber and Nano-silica was introduced. The mechanical properties, such as axial compressive strength and elastic modulus at 28 days were studied by static load test. The results show that the basalt fiber has different influences on the axial compressive strength and elastic modulus of recycled aggregate concrete. When the replacement rate is 50%, the optimum basalt fiber content corresponding to the maximum values of axial compressive strength and elastic modulus at 28 days is 2 kg·m-3. When the replacement rate is 100%, the optimum BF content is 2 kg·m-3 and 1 kg·m-3, respectively. When the replacement rate is no more than 50%, the optimum Nano-silica content is 6%, and when the replacement rate exceeds 50%, the optimum Nano-silica content is 8%in terms of axial compressive strength and elastic modulus. The results show that the recycled concrete made by the manufacturing technology can be applied to engineering practice. © 2019 Editura Politechnica. All rights reserved.

关键词： Elastic moduli

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Mechanics performances of different basalt-fiber-reinforced recycled aggregate concretes subjected to compression test

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Journal of engineering Science and Technology Review 2020年第2期13卷 92-98页

作者： Xianggang, Zhang Yahong, Ding Junna, Yang Henan Province Engineering Laboratory of Eco-architecture and the Built Environment Henan Polytechnic University Jiaozuo454003 China School of Civil Engineering Henan Polytechnic University Jiaozuo454003 China

To reveal the mechanical relationship of the compressive strength indexes of two kinds of basalt-fiber-reinforced recycled aggregate concrete (BFRRAC), seven groups of cubic and prismatic standard samples were prepared, respectively. The tests of mechanical properties were carried out under uniaxial compression tests, then the deformation characteristics and failure modes of the two kinds of samples were obtained. The conversion relationships of the compressive strength of two kinds of samples were established. The influences of replacement ratio of recycled coarse aggregate (RRRCA) and basalt fiber content on the elastic modulus were revealed. The function expression of the stressstrain ascending segment and the calculation formula for the elastic modulus of BFRRAC were presented. Results show that with increases of the basalt fiber content, the surface spalling phenomenon of BFRRAC samples becomes less severe. Moreover, the elastic modulus tends to increase. With increase of RRRCA, the elastic modulus of BFRRAC decreases. The obtained conclusions in the study are of important reference value to direct the similar engineering practice. © 2020 School of Science, IHU.

关键词： Elastic moduli

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