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CONTENTS
Volume 19, Number 4, April 2025
 

Abstract
Conventional cementitious materials, while widely used in construction, suffer from inherent drawbacks, particularly low tensile strength, which predisposes them to crack. Fortunately, recent advancements in nanotechnology offer promising avenues for enhancing the properties of these materials. Within the realm of cementitious composites, graphene oxide (GO) has emerged as a nanomaterial of considerable interest due to its ability to significantly improve the strength of mortar and cement paste even at low inclusion levels. These remarkable characteristic positions GO as a potentially superior nano-filler for use in cement composites, paving the way for the development of more efficient, robust, and durable construction materials. This review delves into the existing body of research on GO-reinforced cement composites, specifically focusing on their mechanical performance, microstructural characteristics, workability, and durability. By critically analyzing these aspects, the review aims to identify key strengths and limitations associated with GO incorporation. Furthermore, the review highlights areas for further research that could facilitate the optimization and effective application of GO as a nano-reinforcing agent in cement composites. In conclusion, the review acknowledges the challenges associated with GO implementation while simultaneously emphasizing the exciting potential it holds for the future of construction materials.

Key Words
addition in cementitious materials; admixtures; buildings; cement; cementitious materials; concrete; durability/sustainability; graphene; graphene oxide

Address
(1) Khairul Nazhan Khairul Izwan, Nazirah Mohd Apandi, Warid Wazien Ahmad Zailani, Alia Sofea Shamsol:
Department of Structure and Materials, School of Civil Engineering, College of Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia;
(2) Wei-Kit Chee:
Petronas Research Sdn Bhd, Petronas Research and Scientific, Bangi Government and Private Training Centre Area, 43000 Bandar Baru Bangi, Selangor, Malaysia.

Abstract
Geopolymer cement is a viable and sustainable replacement for conventional Portland cement, drawing attention for its enhanced durability and reduced shrinkage when compared to API Class G cement, alongside its potential to reduce CO2 emissions. This research aims to develop fly ash-based geopolymer cement incorporating graphene oxide (GO) under high pressure high temperature (HPHT) conditions for oil well cementing application. The investigation unfolds in three distinct phases to meet its objectives. Phase 1 identifies the optimal GO concentration, demonstrating that a formulation with 3.83 M NaOH and 0.2% GO achieves a compressive strength of 21.39 MPa. Phase 2 applies this optimal formulation (Formulation OP 1) in functional oil well cementing tests, with rheology showing stable viscosity across temperatures and a thickening time of 3:25 hr at 100 Bc. Phase 3 evaluates compressive strength under varying temperature and pressure, revealing a maximum compressive strength of 25.68 MPa curing at 120°C and 20.68 MPa. Results show that higher temperatures enhance compressive strength, attributed to accelerated geopolymerization and improved pore structure. Experimental validation aligns closely with predictions, with deviations within 7.2%. This study highlights geopolymer cement's capability as a sustainable, high-performance option for challenging oil well settings, presenting a significant advancement over traditional oil well cement solutions.

Key Words
alkaline activator ratio; CCD; CCUS; compressive strength; fluid loss; fly ash; rheology

Address
(1) Mohd Firdaus Habarudin, Nasir Shafiq, Afif Izwan Abd Hamid, Nurul Nazmin Zulkarnain:
Civil Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 32610, Perak, Malaysia;
(2) Mohd Firdaus Habarudin, Nurul Nazmin Zulkarnain:
Carbon Capture, Utilization, and Storage (CCUS) Department, PETRONAS Research Sdn. Bhd., Kajang, 43000 Selangor, Malaysia;
(3) Afif Izwan Abd Hamid:
Renewable Energy and Green Technology, TNB Research Sdn. Bhd., Kajang, 43000 Selangor, Malaysia.

Abstract
Determining an allowable chloride concentration is crucial for assessing durability and service life of reinforced concrete (RC) structures exposed to chloride attack. This study measured corrosion potential and current density in embedded steel within cement mortar mixed with chloride ions and several mineral admixtures. Corrosion potential was quantified across a range of initial chloride concentrations (0.0% to 0.8% of binder wt.), and corrosion probability was calculated using Monte Carlo simulation. With a 10% coefficient of variation, corrosion probability ranged from 0.0002% to 0.91% with increasing chloride concentration. Relationships between changing corrosion potential, corrosion probability, and service life were plotted against increasing chloride concentration. Higher ground granulated blast furnace slag and fly ash replacement ratios, coupled with reduced chloride concentration, led to reduced corrosion potential and extended service life. A proposed critical chloride concentration of 0.4% of binder mass was conservative, with service life extending to 120% ~ 12% when increased to 0.8%.

Key Words
chloride concentration; fly ash; ground granulated blast furnace slag; Monte Carlo simulation; open circuit potential; service life

Address
(1) Seung-Jun Kwon:
Department of Civil and Environmental Engineering, Hannam University, Daejeon, 34430, Republic of Korea;
(2) Gebremicael Liyew, Hyeong-Ki Kim:
Department of Architectural Engineering, Chosun University, Gwangju 61452, Republic of Korea;
(3) Sung-Cheol Bae:
Department of Architectural Engineering, Hanyang University, Seoul 04763, Republic of Korea;
(4) Seung-Yup Jang:
Department of Transportation System Engineering, Korea National University of Transportation, Gyeonggi-do 16106, Republic of Korea.

Abstract
In the present work, nonlinear partial differential equations in its original form are used to obtain soliton solutions for the problem. The equations considered are of practical use since most of them have many applications in our daily life. In particular, the soliton solutions of nonlinear partial differential equations are obtained using a modified version of the expfunction method. Mathematical code for modified exp-function method is developed by making use of the software named MAPLE. Three solutions as assumption-I, assumption-II and assumption-III are utilized with modified form of exp-function method equation. In order to interpret obtained soliton solutions into meaningful form, aid of graphical simulations would be taken using computer softwares MATHEMATICA and MATLAB.

Key Words
assumptions; code; equations; exp-function method; MATHEMATICA and MATLAB; soliton solutions

Address
(1) Sami Alghamdi:
Electrical and Computer Engineering Department, King Abdulaziz University, Jeddah, Saudi Arabia;
(2) Muhammad Asad Iqbal:
Department of Mathematics, University of Poonch Rawalakot, AJK, Pakistan;
(3) Muzamal Hussain:
Department of Mathematics, University of Sahiwal, 57000, Sahiwal, Pakistan;
(4) Muhammad Taj:
Department of Mathematics, University of Azad Jammu and Kashmir, Muzaffarabad 13100, Pakistan;
(5) Mohamed Amien Khadimallah, Elimam Ali:
Department of Civil Engineering, College of Engineering in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia;
(6) Abdur Rauf:
Department of Chemistry, University of Sahiwal, 57000, Sahiwal, Pakistan.

Abstract
The LS DYNA software is employed to simulate the behavior of composite and reinforced concrete shear walls under explosion loading in two directions (parallel and perpendicular to the wall) in this manuscript. The composite wall is specifically engineered to match the RC shear wall, using a corrugated steel sheet within the wall structure. Therefore, the accuracy of the numerical simulations has been verified by comparing them with comparable laboratory models and data. The results of this study are important: they offer a thorough comprehension of the response of these walls to blast loading. Analysis of the horizontal and vertical displacements, von Mises stress, effective plastic strain, and damage to the walls are conducted at various explosion intensities. The behaviors of the two walls are then compared and contrasted. The presence of a corrugated steel sheet within the frame of the composite wall results in reduced horizontal and vertical displacements compared to the RC shear wall. The steel frame elements experience a greater von Mises stress when subjected to force perpendicular to the wall plane in the composite wall. Element damage occurs earlier under vertical loading parallel to the wall plane compared to force perpendicular to the wall plane.

Key Words
blast; composite shear wall; corrugated steel plate; LS DYNA; RC shear wall

Address
Faculty of Civil Engineering and Architecture, Shahid Chamran University of Ahvaz, Ahvaz, Iran.

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