Article
Construction & Building Technology
Mohamed Abdellatief, Mohamed Abd Elrahman, Aref A. Abadel, Muhammad Wasim, Ahmed Tahwia
Summary: This study compares the engineering characteristics and economic and ecological impacts of ultra-high performance geopolymer concrete (UHPGC) with conventional ultra-high performance concrete (UHPC). The results show that UHPGC has lower flowability compared to UHPC, but it still exhibits relatively high flowability. The setting times of geopolymer concrete are faster than UHPC, and the early compressive strength of UHPGC is higher than UHPC at 7 days but lower at 28 days. Microstructural investigations reveal that UHPGC has more compact and homogeneous microstructures at 7 days, but becomes less compact and homogeneous after 28 days. Additionally, the production of UHPGC results in lower CO2 emissions, embodied energy, and cost compared to UHPC. Therefore, UHPGC can be considered as an affordable and environmentally beneficial alternative to conventional UHPC in the era of sustainable development.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
Ahmed M. Tahwia, Gamal M. Elgendy, Mohamed Amin
Summary: The study aims to develop UHPC mixture proportions using supplementary cementitious materials (SCMs) and eco-efficient material CEM III to enhance sustainability and affordability. By replacing a larger portion of Portland cement with blast furnace cement and utilizing sustainable materials like fly ash and granulated blast furnace slag, the study achieved optimal partial replacements for different materials and obtained affordable and sustainable ultra-high-performance concrete with satisfactory mechanical properties.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2022)
Article
Construction & Building Technology
Amin K. Akhnoukh, Chelsea Buckhalter
Summary: UHPC is a new type of concrete with superior mechanical properties and long-term performance, which has been increasingly used in construction markets worldwide, especially in bridge construction. However, barriers such as the lack of design codes and specific requirements for batching, mixing, and curing are hindering the widespread adoption of UHPC.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2021)
Article
Construction & Building Technology
Thong M. Pham, John Davis, Ngoc San Ha, Emad Pournasiri, Feng Shi, Hong Hao
Summary: The study developed ultra-high-performance rubberized concrete incorporating different rubber contents and steel fibres, finding that the compressive strength decreased with increasing rubber content but remained higher compared to other rubberized concretes. The dynamic compressive strength and energy absorption of the UHPRuC were sensitive to strain rate and increased with rubber content.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Construction & Building Technology
Lingqi Meng, Yahong Ding, Lei Li, Jiuqi Wei, Mingzhe Li, Junlei Wang, Shaohua Cao, Jingbiao Liu
Summary: Ultra-high performance concrete (UHPC) with fine lightweight aggregate (L-UHPC) was developed and its dynamic properties were investigated. The L-UHPC showed sensitivity to strain rate, experiencing more damage, higher peak stress, and greater energy absorption at higher strain rates. Steel fiber shape had minimal effect on both quasi-static and dynamic properties. An empirical formula for dynamic increase factor (DIF) was proposed. The findings contribute to understanding the dynamic characteristics of concrete with ultra-high strength and low density.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Linbin Wang, Gengying Li, Chunbao He, Yanfeng Tang, Biliang Yi
Summary: Ultra-high-performance concrete (UHPC) with excellent durability and strength has great potential in civil engineering. This study optimized the mix proportion of UHPC cured in normal conditions and used nano carbon black (NCB) to improve its properties. Results showed that by using the optimal mix proportion of silica sand, steel fiber, and superplasticizer, and adding NCB, the strength and workability of UHPC can be significantly enhanced. Furthermore, the addition of NCB refined the pore size distribution and decreased the porosity of UHPC.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2022)
Article
Construction & Building Technology
Zhengyan Shen, Hongguang Zhu, Zhijian Zhao, Sen Pang, Zonghui Li, Sen Yang, Pengpeng Cao, Sinuo Lin
Summary: High-performance artificial aggregate was prepared using high dosage recycled concrete powder (RCP), which addressed the pollution and shortage of resources caused by waste concrete powder and improved the performance of concrete.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Review
Construction & Building Technology
Tien-Dung Nguyen, Rachid Cherif, Pierre-Yves Mahieux, Jerome Lux, Abdelkarim Ait-Mokhtar, Emilio Bastidas-Arteaga
Summary: Using artificial intelligence methods to predict the mechanical performance of recycled aggregate concretes is a promising approach. This study provides an extensive literature review on AI methods for predicting the performance of recycled aggregate concretes and performs sensitivity analysis. The benefits and drawbacks of various algorithms are highlighted, and the study emphasizes that the performance of AI algorithms is dependent on data structure and hyperparameter selection.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Chemistry, Physical
Xin Zhao, Lei Cai, Xiaohua Ji, Wei Zeng, Jintao Liu
Summary: The study found that adding polyethylene fibers with high length and diameter benefits the compressive and tensile strength of ultra-high performance concrete (UHPC), while increasing the fiber diameter and elastic modulus significantly enhances its tensile strain capacity and energy absorption capacity.
Article
Construction & Building Technology
Ibrahim Y. Hakeem, Mohamed Amin, Ibrahim Saad Agwa, Mahmoud H. Abd-Elrahman, Omar Mohamed Omar Ibrahim, Mohamed Samy
Summary: Egypt is the largest producer of rice straw, but the disposal of this waste in landfills and open fields has caused environmental damage. Moreover, eggshells used in bakeries, restaurants, and poultry farms are usually discarded in landfills, posing health hazards. However, grinding eggshells into nanoparticles, known as nano eggshell powder (NEP), can increase its activity. This study examined the characteristics of ultra-high-performance concrete (UHPC) produced using eco-friendly components, rice straw ash (RSA) and NEP, as partial cement substitutes. The results showed that using RSA and NEP as pozzolanic materials improved concrete characteristics, reduced cement content, and reduced environmental contamination.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2023)
Review
Construction & Building Technology
Chengcheng Wen, Peng Zhang, Juan Wang, Shaowei Hu
Summary: This paper introduces the enhancement mechanisms of various fibers on ultra-high-performance concrete (UHPC) and reviews the effects of these fibers on the mechanical properties, fiber-matrix bonding behavior, and durability of UHPC. The study also summarizes empirical formulas and theoretical models for predicting the properties of UHPC. The results suggest that fibers have the potential to enhance the strength of UHPC and the optimal fiber volume fraction may depend on the fiber type.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Engineering, Mechanical
Taotao Feng, Fengjuan Wang, Yongshan Tan, Chengjun Yue, Wenxiang Xu, Zhiyong Liu, Zhiqiang Yang, Yirui Wu, Jinyang Jiang
Summary: The dynamic mechanical properties of aeolian sand-based UHPC were studied using experimental and numerical simulation methods. A novel three-dimensional modeling method was proposed and simulation results were found to be consistent with experimental results. The effects of strain rate, fiber content, and matrix strength on the stress-strain relation and energy evolution process were quantitatively discussed.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2022)
Article
Construction & Building Technology
Hongyan Chu, Li Gao, Jianjian Qin, Jinyang Jiang, Danqian Wang
Summary: This study designed high elastic modulus ultra-high-performance concrete (HEMUHPC) and investigated the effects of alumina micro-powder on its workability, microstructure, and mechanical properties. The addition of alumina micro-powder reduced the porosity and threshold pore diameter of HEMUHPC, leading to an increase in flexural strength, compressive strength, and elastic modulus. The optimal content of alumina micro-powder was found to be 10%.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Environmental Sciences
Sahar A. Mostafa, Nashaat Ahmed, Ibrahim Almeshal, Bassam A. Tayeh, Mohamed S. Elgamal
Summary: This research investigates the effect of different thermal treatment methods on the behavior of ultra-high-performance concrete (UHPC) using nanorice husk ash (NRHA). Experimental tests and microstructural analysis show that the addition of NRHA can significantly improve the mechanical properties of UHPC. An artificial neural network (ANN) model is also built to predict UHPC properties, which demonstrates a reliable correlation between input and output variables.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Review
Construction & Building Technology
Ahmed A. El-Abbasy
Summary: This study reviews the literature on the mechanical properties, optimum mixing ratios, and microstructure analysis of ultra-high-performance fiber concretes (UHPFC). It highlights the critical influence of fiber geometry and properties on the performance of steel fiber concretes, as well as the use of coarse aggregates to produce practical, cost-effective, and green UHPFC.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2022)
Article
Multidisciplinary Sciences
Mohammad Reza Khosravani, Filippo Berto, Majid R. Ayatollahi, Tamara Reinicke
Summary: This paper discusses the effects of two printing parameters on the mechanical behavior of additively manufactured components. Based on experimental results, the strength and stiffness of the examined specimens are determined, and the dependency of the strength and elastic modulus of 3D-printed parts on the raster orientation is documented.
SCIENTIFIC REPORTS
(2022)
Article
Automation & Control Systems
Markus Baum, Fabian Jasser, Michael Stricker, Denis Anders, Simone Lake
Summary: This study focuses on the simulation and experimental validation of the injection molding filling process using Ansys CFX. The numerical model nicely fits the experimental results, despite some slight deviations in the early filling stages.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Engineering, Mechanical
Majid R. R. Ayatollahi, Parham Rezaeian, Amir Nabavi-Kivi, Mohammad Reza Khosravani
Summary: This study investigates the effect of heat treatment on the tensile, flexural, and fracture strength of PLA specimens made by the FDM technique. Annealing at different temperatures (80℃, 100℃, 120℃) was conducted on dog bone and ECT specimens to evaluate the mechanical and fracture performance of the FDM-PLA parts. Fracture behavior was assessed using EMC, J-integral, ASED, and MTS criteria, and compared with experimental results. Heat treatment significantly improved the structural integrity of FDM specimens, with a 57% increase in fracture resistance.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Materials Science, Multidisciplinary
Kerstin Weinberg, Sam Aghayan
Summary: In this study, a variational approach is used to derive a thermodynamically consistent model for the dynamics of bubble cavitation in soft gels. The model considers the competition of different energy contributions and introduces a non-local energy contribution to account for interactions with neighboring bubbles. The importance of this research lies in the demand for biomedical applications and the replication of soft body parts using gels.
MECHANICS OF MATERIALS
(2023)
Article
Automation & Control Systems
Denis Anders, Ulf Reinicke, Markus Baum
Summary: This contribution investigates the effectiveness of helical static mixers in various arrangements and flow configurations. Numerical analysis using ANSYS Fluent 2020 R2 demonstrates the application limits of static mixers for enhancing heat transfer in cooling channels of machine tools. The study reveals that static mixers can be optimally applied as heat exchange intensifiers depending on flow speed, heat flow, and thermal conductivity of the tool. The research focuses on single-phase flow in circular cross-sections and straight channel geometries, with a case study on the cooling of an injection mold as a representative application example. The results show that static mixing elements are highly effective in enhancing heat transfer, particularly in low to medium Reynolds number flows, close-contour cooling, high heat fluxes, and high thermal conductivity tooling materials.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2023)
Article
Engineering, Mechanical
Bahador Bahrami, Hossein Talebi, Majid R. Ayatollahi, Mohammad Reza Khosravani
Summary: This research demonstrates the application of artificial neural network (ANN) in predicting fracture under mixed-mode I/II loadings. By analyzing the importance of different input factors, crack parameters and material properties are selected as input data. Multiple ANN models are trained and optimized using different algorithms. The optimized models show low errors and high accuracy in predicting fracture, indicating the effectiveness and potential wide range application of data-driven fracture predictions compared to traditional physics-based criteria.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Mechanics
A. Nabavi-Kivi, M. R. Ayatollahi, S. Schmauder, M. R. Khosravani
Summary: Understanding the mechanical response of polymer components fabricated by fused deposition modeling (FDM) is crucial. This study investigates the effects of raster angle and layer orientation on the tensile properties and fracture toughness of ABS specimens produced by FDM. The results show that different raster angles and layer orientations result in different fracture loads, as observed through analysis of fracture surfaces and examination of fracture paths.
PHYSICAL MESOMECHANICS
(2023)
Article
Polymer Science
Mohammad Reza Khosravani, Hadi Sadeghian, Majid R. Ayatollahi, Tamara Reinicke
Summary: Due to the wide scope of applications of additive manufacturing (AM) in making final products, it is crucial to determine the mechanical strength and structural integrity of AM parts. This study focuses on the pin-bearing test to evaluate the stress response of fasteners, plates, and holes. Two polymer materials were used to fabricate samples, and the effects of specimen width and hole diameter on pin-bearing strength were investigated. Tensile tests were performed, and the failure behavior was analyzed using scanning electron microscopy and digital image correlation technique. The results provide insights for designing AM parts with improved mechanical strength.
Article
Materials Science, Multidisciplinary
Mohammad Reza Khosravani, Payam Soltani, Tamara Reinicke
Summary: The shape of the overlap area in adhesively bonded joints has a significant impact on the structural integrity and load carrying capacity of 3D-printed joints. Stepped-shape designs in the bonding area show better performance compared to conventional single-lap joints. Experimental and finite element simulation results reveal the fracture load and damage evolution mechanism in these 3D-printed bonded joints. This technique has the potential to be a competitive alternative to conventional 3D-printed single-lap joints.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Mohammad Reza Khosravani, Peter Frohn-Soerensen, Bernd Engel, Tamara Reinicke
Summary: This research investigates the fracture behavior and crack propagation of cracked plates in 3D printing. Different fracture modes were obtained by changing the angle between the crack and the applied load. The study uses stereolithography (SLA) technique to fabricate specimens and finite element method and digital image correlation technique to determine stress intensity factors and strain field.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Dhananjay Phansalkar, Deepak B. Jadhav, Kerstin Weinberg, Michael Ortiz, Sigrid Leyendecker
Summary: This paragraph introduces a phase field approach for fracture modeling, proposing a variational method based on spatial adaptivity. By optimizing the energy functional, the displacement, phase field, and optimal regularisation length are determined locally, and the computed optimal regularisation length is used for local mesh refinement, resulting in significant computational savings.
FORCES IN MECHANICS
(2023)
Article
Materials Science, Multidisciplinary
Kai Partmann, Christian Wieners, Kerstin Weinberg
Summary: In this work, two non-local approaches to dynamic fracture are investigated: a novel peridynamic formulation and a variational phase-field approach. The chosen continuum-kinematics-based peridynamic model extends the current peridynamic models by introducing surface and volume-based interactions. The phase-field fracture approach optimizes the body's potential energy and provides a reliable method for predicting fracture in finite element computations.
INTERNATIONAL JOURNAL OF FRACTURE
(2023)
Article
Engineering, Manufacturing
Mohammad Reza Khosravani, Denis Anders, Tamara Reinicke
Summary: This study investigates the influence of post-processing on the fracture behavior of 3D-printed polymer components. The results show that while post-processing can improve the surface finish of the parts, it reduces their fracture toughness.
CIRP JOURNAL OF MANUFACTURING SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Multidisciplinary
K. Weinberg, L. Stainier, S. Conti, M. Ortiz
Summary: In this study, we utilize game theory to propose a data-driven approach for solid mechanics, which offers advantages in practicality and effectiveness. Unlike previous cooperative game methods, this approach can directly determine effective material laws from data and simplify the resolution of conventional displacement boundary-value problems. Compared to supervised machine learning methods, the proposed approach is unsupervised, ansatz-free, and parameter-free.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Proceedings Paper
Construction & Building Technology
Mohammad Reza Khosravani, Tamara Reinicke
Summary: This study investigates the fracture behavior of PLA-wood composites produced by 3D printing. The mechanical characteristics of intact and defected specimens are compared, and the influence of raster orientation on fracture behavior is examined.
4TH INTERNATIONAL CONFERENCE ON STRUCTURAL INTEGRITY (ICSI 2021)
(2022)
