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An experimental study on early age compression and shear strength properties of mixed clay soil

Arabian Journal of Geosciences 2024年第2期17卷 1-14页

作者： Abbas, Azhar Akbar, Muhammad Huali, Pan Zar, Ali Ramzan, Samar Hussain, Zahoor Department of Geotechnical Engineering Tongji University Shanghai China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu China Sir Syed University of Engineering & Technology Karachi Pakistan Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin China Department of Civil Engineering University of Engineering and Technology Lahore Lahore Pakistan Zhengzhou University Zhengzhou China

Clay mixed soil is a combination of clay and soil components that may be used as the core of earth dams and the foundation for building and road construction. Up until now, significant research work has been carried out to design cement-based clay materials; however, only a couple of studies have been reported in the literature on earth-based materials. The methodology portion provides an overview of the different materials, tools, and protocols used during work to develop ways to earth-based materials and study their early age compression strength along with their shear strength. Finally, it summarizes all the results and the outcome of the experimental work done. The probability of producing an object using earth-based material was examined. Improvement in the compressive strength in the early age of strength by adding additives like bentonite and rice husk was assessed in this study. Three clayey soil samples were investigated. The undrained shear strength based on an unconfined compression test (UCT) over those samples was measured by varying the moisture content (MC). After performing all these tests, a relationship was developed between the UCT and vane shear test (VST) undrained shear strengths of the selected soil samples. Clay samples with different mix designs were investigated, and building components were printed out to check the early age shear strength development and printable properties of different mix designs. This study will lay the foundation for further research on different aspects relating to the emerging technology of 3D clay printing in Pakistan.

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Influence of Mix Proportioning Parameters and Curing Regimes on the Properties of Ultra-High Strength Alkali-Activated Concrete

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SSRN 2023年

作者： He, Haiyu Zhang, Rong Song, Yuhuan Zhi, Xudong Fan, Feng Key Lab of Structures Dynamic Behaviour and Control The Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China

This study investigates the influence of mix proportioning parameters and curing regimes on the material properties of alkali-activated binder-based ultra-high strength concrete (AAB-UHSC). The effects of five groups of mix proportioning parameters (i.e., fly ash replacement ratio, silica fume replacement ratio, alkali to binder ratio, water glass modulus, and steel fiber content) and three curing regimes(i.e., ambient curing, standard curing, and hybrid curing) on the workability, compressive strength, flexural strength and microstructure development of AAB-UHSC were systematically evaluated. The results indicated that increasing the steel fiber and silica fume dosage negatively affected the flowability of freshly mixed AAB-UHSC. There existed an optimal alkali-to-binder ratio and water glass modulus in terms of flowability, compressive strength, and flexural strength, but the fly ash replacement ratio had a complex effect on the material performance of the AAB-UHSC. The microstructures of the specimens cured in hybrid curing regimes were denser, and fewer cracks were observed, which resulted in higher strength compared to specimens cured under ambient curing and standard curing conditions. The three types of curing regimes adopted barely alter the phases and molecular bonds of hydration products based on the XRD and FTIR results. In addition, the correlations between the compressive strength of the AAB-UHSC obtained under ambient curing conditions, standard curing conditions, and obtained under hybrid curing and standard curing conditions were analyzed, and the fitted results had higher correlation coefficients (R2). © 2023, The Authors. All rights reserved.

关键词： Compressive strength

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Engineering Interfacial Transition Zone with Polymer Nanocomposites: Break the Dilemma between Strength and Damping

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SSRN 2023年

作者： Li, Cheng Tang, Zhuo Zhong, Jing School of Civil Engineering Harbin Institute of Technology Harbin150090 China Key Lab of Structures Dynamic Behavior and Control Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Smart Prevention and Mitigating of Industry and Information Technology Harbin Institute of Technology Harbin150090 China

The damping performance of mortar/concrete is typically promoted by randomly hybridizing with an excessive mass of soft polymers at the cost of strength. We propose a strategy to break the typically observed dilemma between strength and damping by coating aggregates with a thin layer of polyacrylic ester/carbon nanotube (PAE/CNT) nanocomposite, which was readily achieved by dip coating. The coated nanocomposite with high modulus is subjected to high stress at ITZ upon external load due to stress concentration, greatly enhancing its energy dissipation capability. The friction at the nano-interface between CNT and polymer matrix further contributes to the much-improved damping, while the coating layer can densify the ITZ thus increases the strength of the concrete. With an optimal coating mass of 5 mg/g, the compressive strength and loss factor at 28 days are increased by 21.7% and 33.3%, respectively. © 2023, The Authors. All rights reserved.

关键词： Carbon nanotubes

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Mechanical Properties and Microstructure of Ultra-High-Performance Concrete Containing Recycled Aggregates Co-Modified with Steel Fibres and Nanosilica after Exposure to Elevated Temperatures

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SSRN 2023年

作者： Sun, Hang Luo, Liang Yuan, Huan Li, Xi Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Harbin Institute of Technology Harbin150090 China School of Transportation and Science Engineering Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

This study explores the mechanical properties and microstructure of ultra-high-performance concrete with recycled aggregates (UHPC-RA) enhanced by nanosilica (NS) and steel fibers (SF) at elevated temperatures. Thirty-six mixtures, varying in RA replacement rates, SF, and NS content, were prepared and tested for compressive strength, splitting tensile strength, and elastic modulus. Microstructural analyses included SEM morphology, XRD composition, pore size distribution, thermal conductivity, and elemental distribution studies. Results show temperature-induced changes, including SF oxidation and spalling, causing brittle failures due to weakened cementitious matrix and ITZ bonding. Moisture evaporation and hydration product decomposition lead to mass loss. Compressive strength initially increases and then decreases with rising temperatures, while overall splitting tensile strength decreases. Deterioration in UHPC-RA's microstructure is main reason for macroscopic mechanical property degradation. Linear relationships between compressive and splitting tensile strength were established. SEM and XRD confirmed that NS particles contribute to the conversion of CH to C-S-H gels. © 2023, The Authors. All rights reserved.

关键词： Steel fibers

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General Effect of Internal Span of U-shaped Stud on UHPC-NC Interfacial Failure Load 9th

General Effect of Internal Span of U-shaped Stud on UHPC-NC ...

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9th International Conference on Civil Engineering and Materials Science, ICCEMS 2024

作者： Wu, Zhongchong Liu, Dayong Wu, Xiangguo Zhang, Yun Wu, Chengen Lin, Lanri Zhong, Jing Zhu, Hongbing Zhou, Ruiquan You, Xianhui CGN New Energy Holdings Co. Ltd. Beijing China Fujian Provincial Key Laboratory of Multi-Disasters Prevention and Mitigation in Civil Engineering College of Civil Engineering Fuzhou University Fuzhou350108 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of the Industry and Information Technology Harbin Institute of Technology Harbin150090 China College of Civil Engineering Fuzhou University Fuzhou350108 China Sinovel Wind Group Co. Ltd Beijing100086 China Shanghai Electric Wind Power Group Co. Ltd Shanghai200233 China Wind Power Hybrid Tower Co. Ltd Fulaerji161042 China China Power Engineering Consulting Group CO. LTD Beijing100120 China

ISBN: (纸本)9789819615735

To improve the durability design level of the foundation bearing platform for offshore fixed wind power, Ultra-high performance concrete (UHPC) is used as a non-demolding membrane shell system, and a high-performance composite concrete bearing platform structure is formed with on-site pouring of core concrete. The interface performance between the prefabricated UHPC membrane shell and the post cast core concrete has become an important aspect of the overall integrity of the high-performance composite concrete bearing platform. The use of interface shear key design to improve interface integrity is necessary for improving the overall stress of the bearing platform structure. The objective of this study is to assess the effect of the internal span on the shear behavior at the junction of UHPC and normal concrete (NC). © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Ultra-high performance concrete

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Optimized Repairment Properties Of Wer-Cement Composite Material: An Experimental and Simulation Study

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SSRN 2023年

作者： Li, Cong Xiao, Huigang Min, Liu Wang, Wei Xu, Fan School of Civil Engineering Harbin Institute of Technology Heilongjiang China Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Heilongjiang Construction Group Co. Ltd Heilongjiang China

The demand for high-performance repair materials has significantly increased in modern society after the completion of infrastructure construction. However, current research on epoxy resin cement mortar composite lacks theoretical investigation of the proportion of epoxy resin and hardener to prepare a composite material with optimal performance, as it often relies on empirical and previous studies. To address this issue, this study employed E44 and D230 raw materials and determined through theoretical calculations that the optimal ratio for the composite material is 4:1. The best ratio and content were validated by various testing techniques, such as workability, mechanical properties, self-developed shear bond strength test, and impermeability performance. These analyses showed that the composite material's epoxy resin and hardener ratio should be 4:1, with a content of 30%. Additionally, the microstructure of the composite material was analyzed using various testing techniques, including SEM, SEM-EDS, XRD, FTIR, and MIP, to investigate its influence on the ITZ, composition, and pore structure. Furthermore, molecular dynamics simulation was conducted to analyze the mechanical properties, adsorption energy, MSD, and RDF of C-S-H and epoxy resin molecules (cross-linked structures) composite, explaining the effect of water molecules on the composite material from an atomic scale perspective. By combining experimentation and simulation, this study proposed a computationally based ratio design method, which could provide new ideas for research and development of WER-cement composite while created a simple shear bond strength testing method for repair materials. © 2023, The Authors. All rights reserved.

关键词： Epoxy resins

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Real-Time Seismic Damage Simulation for Urban Building Portfolio Based on Basic Building Information and Machine Learning

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SSRN 2023年

作者： Li, Shuang Li, Changqing Huang, Yuwen Zhai, Changhai Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Beijing Glory PKPM Technology Co. Ltd Beijing100013 China

Timely and accurate simulation of seismic damage of the urban building portfolio is important for pre-earthquake planning and post-earthquake rescue. This study proposes a real-time seismic damage simulation method for the urban building portfolio based on the multiple degree-of-freedom (MDOF) shear model and flexural-shear model established by basic building information and the machine learning. The formulas for predicting periods of six types of structures are proposed and the surrogate model-Ⅰ for predicting the key inter-story hysteretic parameters are established to optimize the MDOF models. The surrogate model-Ⅱ is established to rapidly predict the engineering demand parameters and damage states of structures under earthquakes. In terms of the generalization capability, an incremental learning strategy is advised to guarantee the accuracy of the surrogate model-Ⅱ in predicting the seismic damage of other urban building portfolios. The results in two city-scale cases show that the proposed method can achieve real-time seismic damage simulation of urban building portfolio with acceptable accuracy, and it’s not necessary to retrain or only needs minor additional training on the existing surrogate model when applied to other urban building portfolios. © 2023, The Authors. All rights reserved.

关键词： Machine learning

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A Study On Properties of Pu-Cement Composites Repairing Material for Seepage control and Plugging

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SSRN 2023年

作者： Li, Cong Bai, Jinrong Jiang, Ying Xiao, Huigang Wang, Wei Xu, Fan School of Civil Engineering Harbin Institution of Technology Heilongjiang China Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Heilongjiang Construction Group Co. Ltd Heilongjiang China

Composite grouting materials are increasingly becoming the focus of seepage control and plugging research, and in order to improve its mechanical properties and delayed hydration repairment effect without compromising its workability, PU-cement composites grouting materials, in which cement are not the main component, still, requiring a finer particle size and good shape. In this study, the ball-milled cement are prepared to combine with WPU and OPU, creating a new PU-cement composites grouting *** particle size distribution, early strength, and micro-structure of ball-milled cement were analyzed, then the best preparation process was determined as 120min ball-milling time and 0.03% grinding aid doping. The viscosity, swelling rate, bond strength, FTIR, XRD and micro-structure of the composites with different ratios of polymer/cement and OPU/WPU were then examined, especially, based on moisture distribution, a new method to evaluate the impermeability of repair materials is proposed, and the function of ball-milled cement in composites and the interaction mechanism between ball-milled cement and PU were discussed. The results showed that the best performance was achieved with the P/C ratio of 3:1 and 4:1, and the OPU/WPU ratio of 2:1 or 3:1, indicating that PU-cement grouting material can be an ideal choice for underground structure seepage control and plugging. © 2023, The Authors. All rights reserved.

关键词： Cements

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The Micro–Mechanical Mechanism of Multiple Cracking behavior Induced by Interface Strengthening for Ultra–High–Performance Concrete

SSRN

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SSRN 2023年

作者： Du, Junjie Xiao, Huigang Zhang, Fengling Liu, Min Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China School of Civil Engineering Shandong University 17923 Jingshi Road Jinan250061 China

The multiple cracking behavior of ultra–high–performance concrete （UHPC） is strongly dependent on the bridging of cracks by fibers and the spatial strength distribution of matrix. A good match between fiber bridging properties and matrix tensile strength can significantly improve the utilization of fibers and matrix. In this study, a micromechanics based theoretical model is proposed, which can match the matrix tensile strength with the fiber–matrix interface bonding strength. The spatial strength distribution of the matrix and the stress transfer between the fiber and the matrix is considered in the model. Bridge stresses, additional stresses, stress transfer distances, and pulley forces at the crack face for various crack openings are derived. Dense multiple cracks were observed in the UHPC tensile samples at a common condition ( ) designing based on the calculation results. The applicability of the model is validated by comparing the simulation results and the experimental results in previous investigations at the same paraments ( ). With the proposed model, the mechanism of fiber–matrix interface enhancement contributing to the multiple cracking behavior can be understood. The results of this study could provide fundamental insights for the design of UHPC for various ductility and strength requirements. © 2023, The Authors. All rights reserved.

关键词： Fibers

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Tensile Resistance of Novel Interlocked Angle Connectors Used in Steel-Concrete-Steel Sandwich structures

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SSRN 2022年

作者： Zhou, Zhaohui Wang, Yonghui Zhai, Ximei Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China

This paper reports a new interlocked angle connector (IAC) for steel-concrete-steel sandwich structures, and the tensile behaviors of the IACs was also studied in detail by performing the tensile test. There were 14 specimens with different parameters being designed, including embedded depth of IACs, thicknesses of steel sheet, steel angle and bottom plate, side length of steel angle, diameter of steel tube and interlocking bolt. The failure modes and tensile resistances of the proposed IACs were obtained, and three failure modes were identified, including concrete breakout failure, tensile fracture failure of the steel angle and concrete direct shear failure. The main parameters affecting tensile resistance of the IACs were also discussed and analyzed. In addition, analytical models were proposed for predicting the ten¬sile resistances of IACs and their accuracies were also verified via comparing the pre¬dicted values with test results. Finally, the tensile resistances of IACs were compared with those of J-hook connectors, and improved tensile resistance could be observed for the proposed IACs. © 2022, The Authors. All rights reserved.

关键词： Tensile testing

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