Article
Green & Sustainable Science & Technology
Nzar Shakr Piro, Ahmed Salih Mohammed, Samir Mustafa Hamad
Summary: Nanomaterials such as carbon nanotubes have been shown to impact the mechanical properties of construction materials like cement paste. In this study, various mathematical models were proposed to predict the electrical resistivity of cement paste modified with carbon nanotubes, with the artificial neural network model outperforming other models. Additionally, a correlation model was developed to predict compressive strength based on electrical resistivity, showing better performance than models in existing literature.
Article
Construction & Building Technology
Farqad Yousuf, Wei Xiaosheng
Summary: The effects of curing temperature and superplasticizer on the hydration rate and early strength development of cement pastes were investigated using electrical resistivities. It was found that cement pastes obtained at a high temperature or with optimal superplasticizer dosage had faster densification rates.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2022)
Article
Construction & Building Technology
Seongwoo Gwon, Hyunjun Kim, Myoungsu Shin
Summary: This study focuses on the investigation of self-heating characteristics of electrically conductive cement composites (ECCC) and suggests an effective and affordable mix design for ECCC blocks to accelerate the curing of concrete. Carbon black and carbon fibers are used as conductive agents. The presence of carbon fibers is critical for reducing electrical resistivity, while an increase in carbon black content up to 0.8 vol% leads to a drastic decrease in electrical resistivity and achieves the highest average surface temperature of ECCC. The dispersion degree of carbon black affects the trends. The accelerated curing of ordinary cement paste using the ECCC blocks with 0.8 vol% carbon black results in more hydrated phases and a reduction in porosity.
CEMENT & CONCRETE COMPOSITES
(2023)
Article
Engineering, Civil
Hyunwook Choo, Woojin Lee, Changho Lee
Summary: This study evaluated the effect of curing time on the relationship between rho(mix) and UCS of sands grouted with microcement, aiming to estimate UCS over time based on rho(mix). Results show that curing time, particle size, and wc influence both rho(mix) and UCS, establishing a direct relationship between the two. However, the complex impact of curing time on the relation between UCS and rho(mix), as well as the nonlinear increase in UCS with time, presents challenges in capturing the interplay between UCS, rho(mix), and curing time.
GEOMECHANICS AND ENGINEERING
(2021)
Article
Construction & Building Technology
Yubin Jun, Young Hwan Bae, Hong Jae Yim
Summary: The effects of curing conditions on cement mortar setting were investigated using nondestructive methods, electrical resistivity and ultrasonic wave velocity. Nine curing cases with different temperatures and relative humidities were considered. The obtained nondestructive parameters showed different trends according to the changed curing conditions. High relative humidity at constant temperature induced carbonation of calcium hydroxide more than at low relative humidity, resulting in pore refinement by the calcium carbonate precipitation. The carbonation did not affect the solid-phase network in ultrasonic wave velocity, while it affected the electrical resistivity due to the pore water.
MATERIALS AND STRUCTURES
(2023)
Article
Construction & Building Technology
Siwei Ma, Cihang Huang, Prince Baah, Tommy Nantung, Na Lu
Summary: This study investigates the influence of water-to-cement ratios and SAPs on the solid-like behaviors of cement pastes using a rotational rheometer. The results show that the changes in solid-like properties of fresh cement pastes do not necessarily follow the same pattern, suggesting that different aspects of solid-like properties can be attributed to different particle interactions among cement systems.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Materials Science, Characterization & Testing
Navaratnarajah Sathiparan, Pratheeba Jeyananthan
Summary: This study investigates the use of machine learning to predict the compressive strength of Cement stabilised earth blocks (CSEBs) in order to enhance quality control. Different types of soil and cement content were considered, and various machine learning models were proposed. The results show that a combination of cement content, electrical resistivity, and Ultrasonic pulse velocity (UPV) can accurately assess the quality of CSEBs.
NONDESTRUCTIVE TESTING AND EVALUATION
(2023)
Article
Construction & Building Technology
Seongwoo Gwon, Juhyuk Moon, Myoungsu Shin
Summary: The study examines the effects of curing conditions on the self-heating performance of electrically conductive cement composites. The results show that drier curing conditions improve the self-heating capability.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Chemistry, Physical
Jing Zhu, Zijian Qu, Siqi Liang, Baiping Li, Tao Du, Hui Wang
Summary: This paper investigates the effects of carbon dioxide curing on cement paste. Results show that carbon dioxide curing can accelerate cement setting and improve mechanical strength. In addition, carbon dioxide curing also reduces water absorption by unit area.
Article
Materials Science, Ceramics
Yueh-Ting Shih, Yunfeng Shi, Liping Huang
Summary: Physics and chemistry-informed machine learning models were trained using descriptors in the element physical and chemical properties domain. These models successfully predicted the elastic moduli and temperature dependence of electrical resistivity for oxide glasses, and revealed the relationships between predicted glass properties and elemental features.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2022)
Article
Construction & Building Technology
Yuan Sang, Yingzi Yang, Qi Zhao
Summary: This paper reviews the application of resistivity in cement-based materials, including hydration, compressive strength, and ions diffusion. It also focuses on the evolution history, strengths/weaknesses, and prediction accuracy of multi-phase conductive models. The analysis results show the importance of considering the changing model parameters with pore structure. Future works can be done in testing methods, raw materials, testing environments, and conductive models.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Construction & Building Technology
Qiyuan Xiao, Yuxin Cai, Guangcheng Long, Kunlin Ma, Xiaohui Zeng, Zhuo Tang, Wenxu Li, Haixu Wang, Jianwei Peng
Summary: Compared to other curing methods, alternating current curing (ACC) in cement-based materials has the advantages of easy operation and effective quality control. The percolation threshold of carbon black (CB) in fresh paste is determined to be 1 vol% by experiments and simulations, to lower resistivity and improve ACC efficiency. By using fixed voltage and frequency, the effect of ACC on the hydration, compressive strength, and pore structure of CB-cement conductive composite (CBCC) is studied. The results show that ACC greatly shortens setting time and increases compressive strength by improving hydration temperature, resistivity, pore structure, and capillary water absorption.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
Mohamed Esaker, Omar Hamza, David Elliott
Summary: The study investigates the potential application of an in-situ, non-destructive method using electrical resistivity to evaluate the restorative performance of self-healing concrete embedded in soil. Bio-mortar specimens showed greater improvements in electrical resistivity, crack area, water absorption, and absolute porosity compared to control mortar.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Engineering, Civil
Dabo Adama, L. Sebastian Bryson, Ao Wang
Summary: The construction and repair of airfields require a quick and accurate assessment of the subgrade soil strength and stability. Currently, the most widely used technique for determining soil properties is the dynamic cone penetration (DCP) test. This paper explores the use of geophysical measurements such as seismic wave velocity and electrical resistivity to directly quantify soil properties and assess airfield suitability. The results demonstrate the viability of utilizing geophysical methods for airfield design.
TRANSPORTATION GEOTECHNICS
(2023)
Article
Mechanics
Leo Demont, Nicolas Ducoulombier, Romain Mesnil, Jean-Francois Caron
Summary: The majority of extrusion-based concrete additive manufacturing focuses on unreinforced mortar, but the lack of reinforcement limits its industrial development. A new reinforcement method called flow-based pultrusion (FBP) is introduced in this paper, which uses continuous fiber rovings to increase the yield stress of the mortar and create anisotropic concrete.
COMPOSITE STRUCTURES
(2021)
Article
Computer Science, Interdisciplinary Applications
Fan Zeng, Menad Nait Amar, Ahmed Salih Mohammed, Mohammad Reza Motahari, Mahdi Hasanipanah
Summary: This study aims to predict the safety factor (SF) of slopes through machine learning methods improved by the whale optimization algorithm (WOA). Results show that the LSSVM-WOA method performs better than the LSSVM-GSA method, with smaller errors.
ENGINEERING WITH COMPUTERS
(2022)
Article
Engineering, Civil
Ahmed Mohammed, Serwan Rafiq, Kawan Ghafor, Wael Emad, Riyadh Noaman, Ahmed Y. Qasim, Warzer Qadir
Summary: The study found that nanoclay (NC) has a significant impact on the rheological properties and compressive strength of cement paste, improving shear stress and yield stress. Experimental results show that NC-modified cement paste exhibits different performance under different water/cement ratios and temperatures.
IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY-TRANSACTIONS OF CIVIL ENGINEERING
(2022)
Article
Engineering, Geological
Cumaraswamy Vipulanandan, Ahmed Salih Mohammed
Summary: The study quantified the relationship between factors like density, moisture content, shear strength, and failure stresses of soil, showing that the Vipulanandan failure model is more reliable in predicting results.
GEOMECHANICS AND GEOENGINEERING-AN INTERNATIONAL JOURNAL
(2022)
Article
Construction & Building Technology
Nzar Shakr Piro, Ahmed Mohammed, Samir M. Hamad, Rawaz Kurda
Summary: Steel slag can be used as a replacement material in concrete to improve compressive strength and reduce electrical resistivity. Different models have been employed to predict concrete performance, and the most accurate prediction was achieved using an Artificial Neural Network (ANN) model for compressive strength and a Full Quadratic model for electrical resistivity.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Environmental Sciences
Nzar Shakr Piro, Ahmed Salih Mohammed, Samir M. Hamad, Rawaz Kurda
Summary: This study analyzed and modeled the effect of steel slag aggregate substitution in concrete by collecting a large amount of data and using different models for prediction. The study found that factors such as water/cement ratio, steel slag content, fine aggregate content, and coarse aggregate content have an impact on the compressive strength of concrete. In addition, steel slag also affects the electrical conductivity of concrete, and there is a correlation between compressive strength and electrical conductivity.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Chemistry, Physical
Hemn Unis Ahmed, Aso A. Abdalla, Ahmed S. Mohammed, Azad A. Mohammed, Amir Mosavi
Summary: In this paper, multiscale models were developed to predict the compressive strength of fly-ash-based geopolymer mortar. Three different models, linear regression, multinominal logistic regression, and nonlinear regression, were compared and evaluated. The results showed that the nonlinear regression model performed the best. Additionally, the SiO2 percentage of fly ash and the alkaline liquid-to-binder ratio were identified as the most effective parameters for predicting the compressive strength of geopolymer mortar.
Article
Chemistry, Multidisciplinary
Biao He, Sai Hin Lai, Ahmed Salih Mohammed, Mohanad Muayad Sabri Sabri, Dmitrii Vladimirovich Ulrikh
Summary: This study developed a regular random forest model to accurately estimate the environmental impact of blasting. To enhance the model's performance, several techniques were proposed. The results showed that all refined weighted models outperformed the regular model, with the refined weighted RF model using the whale optimization algorithm performing the best. Sensitivity analysis revealed that the powder factor has the most significant impact on the prediction of peak particle velocity.
APPLIED SCIENCES-BASEL
(2022)
Article
Construction & Building Technology
Nzar Shakr Piro, Ahmed Salih Mohammed, Samir M. Hamad, Rawaz Kurda, Bootan S. Qader
Summary: To preserve the environment and conserve natural resources, steel slag recovery has been used to partially replace fine and coarse aggregate in concrete. This study focused on predicting the compressive strength of concrete with steel slag aggregate replacement, using various models. The results showed that the curing time had the most significant impact on the compressive strength, and the artificial neural network (ANN) model performed the best in predicting the compressive strength.
STRUCTURAL CONCRETE
(2023)
Article
Materials Science, Textiles
Muhammad Ahsan Gulzar, Babar Ali, Osama Barakat, Marc Azab, Ahmed M. Najemalden, Ahmed Salih Mohammed, Yasser Alashker
Summary: This study aims to develop eco-friendly and ductile concrete by incorporating ground granulated blast furnace slag (GGBS) and jute fiber (JF). Two concrete families were produced with 0% and 25% GGBS as partial replacements for cement, and JF was added at 0%, 0.25%, and 0.5% volume fractions. The effects of a plasticizer on jute fiber reinforced concrete (JFRC) with GGBS were also studied. Various properties including compressive strength, splitting tensile strength, flexural strength, water absorption, chloride ion penetration depth, and electrical resistivity were examined. The results showed that increasing JF content decreased compressive strength but improved splitting tensile strength and flexural strength. The positive effect of JF on compressive strength was observed in mixes with or without a plasticizer. The negative effects of the hydrophilic nature of JF on water absorption and chloride ion penetration resistance were mitigated by using GGBS and controlling workability.
JOURNAL OF NATURAL FIBERS
(2023)
Article
Chemistry, Multidisciplinary
Ahmed Salih Mohammed, Wael Emad, Warzer Sarwar Qadir, Rawaz Kurda, Kawan Ghafor, Raed Kadhim Faris
Summary: This study tested the effect of three water-reducer additives on the workability and compressive strength of concrete. The results showed that adding water-reducer additives can increase the compressive strength of concrete by 8% to 186%, depending on the type of additive and cement content. The study aimed to establish mathematical models to predict the compressive strength of concrete containing water-reducer additives and investigate the impact of mix proportion on compressive strength.
APPLIED SCIENCES-BASEL
(2023)
Article
Green & Sustainable Science & Technology
Cumaraswamy Vipulanandan, Ahmed Salih Mohammed, Praveen Ramanathan
Summary: This study analyzed the stress intensity factor (K-I) and bond strength tests of oil well cement (class H) with a water-to-cement ratio (w/c) of 0.38. The mechanical properties of the cement paste were tested and qualified, including compressive and flexural strengths. The relationship between elastic modulus and axial strain was obtained using the Vipulanandan p-q model. The bonding strength between the cement and steel tube representing the casing in the borehole was determined at different curing times.
Article
Green & Sustainable Science & Technology
Ahmad Khalil Mohammed, A. M. T. Hassan, Ahmed Salih Mohammed
Summary: To mitigate the negative environmental effects of cement production, the construction industry is adopting eco-friendly approaches, such as using alternative and recycled materials and reducing carbon emissions in concrete production. This study focuses on investigating the factors influencing the compressive strength of concrete containing ground granulated blast furnace slag (GGBFS) at 28 days of age. Statistical modeling techniques were employed to comprehensively analyze the effects of temperature, water-to-binder ratio, GGBFS-to-binder ratio, fine aggregate, coarse aggregate, and superplasticizer on the compressive strength.
Article
Construction & Building Technology
Mohammad Sadegh Barkhordari, Danial Jahed Armaghani, Ahmed Salih Mohammed, Dmitrii Vladimirovich Ulrikh
Summary: This study compares different ensemble models and super learner models for estimating the compressive strength of fly ash concrete. The results show that the separate stacking model with the random forest meta-learner has the highest accuracy in prediction.
Article
Engineering, Geological
Ahmed Salih
Summary: This study found that the addition of 1% NC nanoclay modification reduced the electrical resistivity of water-based mud and increased the yield stress and shear stress limit tolerance. In addition, using the Vipulanandan fluid loss model, it was able to accurately predict fluid loss in the drilling fluids.
GEOMECHANICS AND GEOENGINEERING-AN INTERNATIONAL JOURNAL
(2022)
Article
Computer Science, Interdisciplinary Applications
Jiandong Huang, Panagiotis G. Asteris, Siavash Manafi Khajeh Pasha, Ahmed Salih Mohammed, Mahdi Hasanipanah
Summary: The main objective of this study is to provide an auto-tuning model called cat swarm optimization (CSO) for predicting rock fragmentation. The results of the study show that the CSO model outperforms the particle swarm optimization (PSO) algorithm in terms of its predictive ability in the D-80 formula.
ENGINEERING WITH COMPUTERS
(2022)
