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Nasir Shafiq is a professor in Structural Engineering, Construction, and Materials in civil engineering, University Technology Petronas. He has 30 years of working experience as an academician, researcher, and structural design consultant. His expertise includes: Structural Reliability, High Performance, and Geopolymer Concrete; Building Information Modelling; and Sustainable and Low Carbon Living. He has authored more than 166 papers in the ISI and Scopus indexed journals (Scopus ORCID: 0000-0002-9496-5430).
Silica aerogel possesses an ultra-low thermal conductivity by virtue of its nano-structure. Owing to the fragility of monolithic aerogel, the development and production of aerogel-based insulation materials involve the incorporation of granular aerogel with other materials to form composite materials. In the present study, the application of silica-aerogel-incorporated composite cement paste as render on the roof-top surface is coupled with the installation of a novel silica-aerogel-incorporated composite insulation board below the roof tiles. Control and silica-aerogel-incorporated samples of the composite cement paste and insulation were prepared. Thermal conductivity and strength tests were performed on the samples. A simulation study was performed on a Building Information Model subjected to a tropical climate to project the resultant impact of the cement render coupled with the insulation board on the thermal-energy-efficiency of the roof. For optimization of thermal and strength performances, silica aerogel contents of 4 wt.% and 3 wt.% were selected for the cement render and insulation board, respectively. The projected annual cooling load and energy savings revealed that the application of a 20-mm cement render, coupled with the installation of a 100-mm thick insulation board, is recommended as the optimum roof configuration.
Fouad Ismail; Syed Farhan; Nasir Shafiq; Nadzhratul Husna; Muhammad Sharif; Syed Affan; Arul Veerasenan. Nano-Porous Silica-Aerogel-Incorporated Composite Materials for Thermal-Energy-Efficient Pitched Roof in the Tropical Region. Applied Sciences 2021, 11, 6081 .
AMA StyleFouad Ismail, Syed Farhan, Nasir Shafiq, Nadzhratul Husna, Muhammad Sharif, Syed Affan, Arul Veerasenan. Nano-Porous Silica-Aerogel-Incorporated Composite Materials for Thermal-Energy-Efficient Pitched Roof in the Tropical Region. Applied Sciences. 2021; 11 (13):6081.
Chicago/Turabian StyleFouad Ismail; Syed Farhan; Nasir Shafiq; Nadzhratul Husna; Muhammad Sharif; Syed Affan; Arul Veerasenan. 2021. "Nano-Porous Silica-Aerogel-Incorporated Composite Materials for Thermal-Energy-Efficient Pitched Roof in the Tropical Region." Applied Sciences 11, no. 13: 6081.
Geopolymer cement (GPC) is an aluminosilicate-based binder that is cost-effective and eco-friendly, with high compressive strength and resistance to acid attack. It can prevent degradation when exposed to carbon dioxide by virtue of the low calcium content of the aluminosilicate source. The effect of the concentration of calcium chloride (CaCl2) as the accelerator on the compressive strength and acoustic impedance of GPC for well cement, while exposed to high pressure and high temperatures, is presented. Fly ash from the Tanjung Bin power plant, which is categorized as Class F fly ash according to ASTM C618-19, was selected as the aluminosilicate source for the GPC samples. Sodium hydroxide and sodium silicate were employed to activate the geopolymerization reaction of the aluminosilicate. Five samples with a density of 15 ppg were prepared with concentrations of CaCl2 that varied from 1% to 4% by weight of cement. Findings revealed that the addition of 1% CaCl2 is the optimum concentration for the curing conditions of 100 °C and 3000 psi for 48 h, which resulted in the highest compressive strength of the product. Results also indicate that GPC samples that contain CaCl2 have a smaller range of acoustic impedance compared to that of ordinary Portland cement.
Nurul Zulkarnain; Syed Farhan; Yon Sazali; Nasir Shafiq; Siti Abd Rahman; Afif Abd Hamid; Mohd Habarudin. Reducing the Waiting-On-Cement Time of Geopolymer Well Cement using Calcium Chloride (CaCl2) as the Accelerator: Analysis of the Compressive Strength and Acoustic Impedance for Well Logging. Sustainability 2021, 13, 6128 .
AMA StyleNurul Zulkarnain, Syed Farhan, Yon Sazali, Nasir Shafiq, Siti Abd Rahman, Afif Abd Hamid, Mohd Habarudin. Reducing the Waiting-On-Cement Time of Geopolymer Well Cement using Calcium Chloride (CaCl2) as the Accelerator: Analysis of the Compressive Strength and Acoustic Impedance for Well Logging. Sustainability. 2021; 13 (11):6128.
Chicago/Turabian StyleNurul Zulkarnain; Syed Farhan; Yon Sazali; Nasir Shafiq; Siti Abd Rahman; Afif Abd Hamid; Mohd Habarudin. 2021. "Reducing the Waiting-On-Cement Time of Geopolymer Well Cement using Calcium Chloride (CaCl2) as the Accelerator: Analysis of the Compressive Strength and Acoustic Impedance for Well Logging." Sustainability 13, no. 11: 6128.
Research for alternative binders has become a necessity due to cement’s embodied carbon, climate change, and depletion of natural resources. These binders could potentially reduce our reliance on cement as the sole binder for concrete while simultaneously enhancing the functional characteristics of concrete. Theoretically, the use of finer particles in the cement matrix densifies the pore structure of concrete and results in improved properties. To validate this hypothesis, current research was designed to investigate how the value-added benefits of nano-silica (NS) and metakaolin (MK) in fly ash (FA)-blended cement affect the mechanical and durability characteristics of concrete when used as ternary and quaternary blends. Additionally, the cost–benefit analysis and environmental impact assessment were conducted. It was observed that the synergy of MK and NS used in FA-blended cement had a greater impact on enhancing the functional characteristics of concrete, while 10% MK as ordinary Portland cement (OPC) replacement and 1% NS as an additive in FA-blended OPC concrete was the optimum combination which achieved 94-MPa compressive strength at the age of 91 days and showed more than 25% increment in the flexural and splitting tensile strengths compared to the control mix (MS00). The ultrasonic pulse velocity and dynamic modulus of elasticity were significantly improved, while a significant reduction in chloride migration of 50% was observed. In terms of environmental impact, MS100 (30% FA and 10% MK) exhibited the least embodied CO2 emissions of 319.89 kgCO2/m3, while the highest eco-strength efficiency of 0.268 MPa/kgCO2·m−3 with respect to 28-day compressive strength was exhibited by MS101. In terms of cost–benefit, MS00 was determined the cheapest, while the addition of MK and NS increased the cost. The lowest cost of producing 1 MPa was exhibited by MS01 with a merely 0.04-$/MPa/m3 reduction compared to MS00.
Rabinder Kumar; Nasir Shafiq; Aneel Kumar; Ashfaque Ahmed Jhatial. Investigating embodied carbon, mechanical properties, and durability of high-performance concrete using ternary and quaternary blends of metakaolin, nano-silica, and fly ash. Environmental Science and Pollution Research 2021, 1 -15.
AMA StyleRabinder Kumar, Nasir Shafiq, Aneel Kumar, Ashfaque Ahmed Jhatial. Investigating embodied carbon, mechanical properties, and durability of high-performance concrete using ternary and quaternary blends of metakaolin, nano-silica, and fly ash. Environmental Science and Pollution Research. 2021; ():1-15.
Chicago/Turabian StyleRabinder Kumar; Nasir Shafiq; Aneel Kumar; Ashfaque Ahmed Jhatial. 2021. "Investigating embodied carbon, mechanical properties, and durability of high-performance concrete using ternary and quaternary blends of metakaolin, nano-silica, and fly ash." Environmental Science and Pollution Research , no. : 1-15.
Modern residential roofs in Malaysia mainly employ red and brown roof tiles due to aesthetic factors and the ability of the roof surface to reflect or retard heat transfer is typically not considered the main priority. The present article reveals the findings of a study on the effect of roof tile colour on heat conduction transfer through roof tiles and ceiling boards, roof-top surface temperature and cooling load. Findings suggest that the selection of white roof tiles significantly reduces the peaks of heat conduction transfer and roof-top surface temperature as well as the values of heat conduction transfer and roof-top surface temperature throughout diurnal profiles, which consequently reduces hours of indoor thermal discomfort and use of air-conditioners in indoor spaces. A decline in peak roof-top surface temperature of up to 16.00 °C that results in annual energy savings of up to 13.14% can be achieved when the roof tile colour is changed from red to white. Further research on the development of solar-reflective paint or coating products that can significantly increase the solar reflectance values of non-white roof tiles are essential to overcome issues related to maintenance difficulties and lack of preference among house buyers towards white roof tiles.
Syed Farhan; Fouad Ismail; Osamah Kiwan; Nasir Shafiq; Azni Zain-Ahmed; Nadzhratul Husna; Afif Hamid. Effect of Roof Tile Colour on Heat Conduction Transfer, Roof-Top Surface Temperature and Cooling Load in Modern Residential Buildings under the Tropical Climate of Malaysia. Sustainability 2021, 13, 4665 .
AMA StyleSyed Farhan, Fouad Ismail, Osamah Kiwan, Nasir Shafiq, Azni Zain-Ahmed, Nadzhratul Husna, Afif Hamid. Effect of Roof Tile Colour on Heat Conduction Transfer, Roof-Top Surface Temperature and Cooling Load in Modern Residential Buildings under the Tropical Climate of Malaysia. Sustainability. 2021; 13 (9):4665.
Chicago/Turabian StyleSyed Farhan; Fouad Ismail; Osamah Kiwan; Nasir Shafiq; Azni Zain-Ahmed; Nadzhratul Husna; Afif Hamid. 2021. "Effect of Roof Tile Colour on Heat Conduction Transfer, Roof-Top Surface Temperature and Cooling Load in Modern Residential Buildings under the Tropical Climate of Malaysia." Sustainability 13, no. 9: 4665.
In current practice, the performance-based concrete mix (PBCM) approach has become quite popular because it enhances the quality of materials that are fundamentally necessary for a particular situation. In the present study, experimental analysis is performed to determine the optimal mechanical properties and microstructural characteristics of concrete for sustainable development and cost effectiveness. Specifically, a mixture of high-volume fly ash (FA) and ultrafine calcium carbonate (UFCC) is investigated as a partial substitution of cement. For optimizing the concrete’s performance, various curing regimes are applied to evaluate the best conditions for obtaining ideal mechanical and microstructural properties. The results show that concrete containing 10% UFCC with a mean particle size of 3.5 µm blended with 40% FA yielded the best performance, with an enhancement of 25% in the compressive strength in the early age. Moreover, the UFCC improved the compactness and refined the interstitial transition zone (ITZ). However, the effects of the different curing methods on the concrete’s strength were insignificant after 28 days.
Norzaireen Azmee; Yassir Abbas; Nasir Shafiq; Galal Fares; Montasir Osman; M. Iqbal Khan. Enhancing the Microstructure and Sustainability of Ultra-High-Performance Concrete Using Ultrafine Calcium Carbonate and High-Volume Fly Ash under Different Curing Regimes. Sustainability 2021, 13, 3900 .
AMA StyleNorzaireen Azmee, Yassir Abbas, Nasir Shafiq, Galal Fares, Montasir Osman, M. Iqbal Khan. Enhancing the Microstructure and Sustainability of Ultra-High-Performance Concrete Using Ultrafine Calcium Carbonate and High-Volume Fly Ash under Different Curing Regimes. Sustainability. 2021; 13 (7):3900.
Chicago/Turabian StyleNorzaireen Azmee; Yassir Abbas; Nasir Shafiq; Galal Fares; Montasir Osman; M. Iqbal Khan. 2021. "Enhancing the Microstructure and Sustainability of Ultra-High-Performance Concrete Using Ultrafine Calcium Carbonate and High-Volume Fly Ash under Different Curing Regimes." Sustainability 13, no. 7: 3900.
This paper presents an experimental investigation on geopolymer cement formulations for enhancing oil-well integrity. Fresh slurry properties, mixability, density, free-water, and rheology were determined for possible field applications. The compressive strength and expansion characteristics were studied for the durability and integrity of the well system. Mix formulations complied with the requirements of API RP 10B-2. All formulations showed homogeneous mixability, rheological properties, the plastic viscosity (PV), and yield point (YP) were increased from 48 cP to 104 cP and 3.8 N/m2 12.4 N/m2, respectively, with the increase of the dosage of elastomeric type expandable material (R additive). The highest compressive strength of 15 MPa was obtained using 10% R additive in the mix-blend after 60 days of curing. Increasing the amount of R additive provides the optimum strength at 10.4 MPa with design 2, 3, and 4. The linear expansion was increased to about 1% at 60 days with 20% and 25% of the R additive dosage. Design of Experiment (DOE) was performed for setting three factors: curing time (A), curing temperature (B), and concentration of R additive (C) to optimize the linear expansion (response).
Siti Humairah A. Rahman; Nurul Nazmin Zulkarnain; Nasir Shafiq. Experimental Study and Design of Experiment Using Statistical Analysis for the Development of Geopolymer Matrix for Oil-Well Cementing for Enhancing the Integrity. Crystals 2021, 11, 139 .
AMA StyleSiti Humairah A. Rahman, Nurul Nazmin Zulkarnain, Nasir Shafiq. Experimental Study and Design of Experiment Using Statistical Analysis for the Development of Geopolymer Matrix for Oil-Well Cementing for Enhancing the Integrity. Crystals. 2021; 11 (2):139.
Chicago/Turabian StyleSiti Humairah A. Rahman; Nurul Nazmin Zulkarnain; Nasir Shafiq. 2021. "Experimental Study and Design of Experiment Using Statistical Analysis for the Development of Geopolymer Matrix for Oil-Well Cementing for Enhancing the Integrity." Crystals 11, no. 2: 139.
This experimental study investigated the effects of polyvinyl alcohol (PVA) and copper-coated steel (CCS) on the mechanical properties and the post cracking behavior of fiber reinforced concrete (FRC). In designing high-performance concrete mixes, cement replacement materials are the essential ingredients. Therefore, the research objective was to investigate PVA and CCS fiber’s post-cracking performance in 100% cement concrete and concrete with 80% cement and 20% fly ash. The fiber content was fixed as a 0.3% volumetric fraction. CSS fibers required 15% more superplasticizer to achieve the desired slump of fresh concrete than the PVA fibers. Simultaneously, CCS fibers showed a 10% higher compressive strength than the concrete made of PVA fibers. Both fibers exhibited a similar effect in developing tensile and flexural strength. PVA fibers showed a value of 47 Gpa of secant modulus, and CCS fibers resulted in 37 Gpa in 100% cement concrete. In post-cracking behavior, CCS fibers showed better performance than the PVA fibers. The reason for this is that CCS showed 2.3 times the tensile strength of the PVA fibers. In comparing the two concretes, fly ash concrete showed about 10% higher compressive strength at 56 days and about 6% higher tensile and flexural strength. Similarly, fly ash concrete showed more than 15% first crack strength and flexural toughness than the 100% cement concrete in post-cracking behavior. Fiber-reinforced concrete containing PVA or CCS fibers showed enhanced post-cracking characteristics and its use could be preferred in structural applications.
Asif Jalal; Luqmanul Hakim; Nasir Shafiq. Mechanical and Post-Cracking Characteristics of Fiber Reinforced Concrete Containing Copper-Coated Steel and PVA Fibers in 100% Cement and Fly Ash Concrete. Applied Sciences 2021, 11, 1048 .
AMA StyleAsif Jalal, Luqmanul Hakim, Nasir Shafiq. Mechanical and Post-Cracking Characteristics of Fiber Reinforced Concrete Containing Copper-Coated Steel and PVA Fibers in 100% Cement and Fly Ash Concrete. Applied Sciences. 2021; 11 (3):1048.
Chicago/Turabian StyleAsif Jalal; Luqmanul Hakim; Nasir Shafiq. 2021. "Mechanical and Post-Cracking Characteristics of Fiber Reinforced Concrete Containing Copper-Coated Steel and PVA Fibers in 100% Cement and Fly Ash Concrete." Applied Sciences 11, no. 3: 1048.
This paper presents the experimental investigation of the influence of fly ash on fresh concrete and hardened concrete mechanical properties, i.e., compressive, tensile, and bond strength. The fly ash content was used from a 5% replacement to a 50% replacement of OPC. The optimum replacement level of fly ash was observed between 15% to 30% for achieving high compressive strength. Whereas highest bond strength was achieved using 10% to 15% fly ash. The effects of fly ash were much pronounced after 28 days curing, such as at 90 and 180 days.
Nasir Shafiq; Muhammad Afiq Ammar. An Experimental Assessment on the Performance of Fly Ash in Concrete. Lecture Notes in Civil Engineering 2021, 458 -467.
AMA StyleNasir Shafiq, Muhammad Afiq Ammar. An Experimental Assessment on the Performance of Fly Ash in Concrete. Lecture Notes in Civil Engineering. 2021; ():458-467.
Chicago/Turabian StyleNasir Shafiq; Muhammad Afiq Ammar. 2021. "An Experimental Assessment on the Performance of Fly Ash in Concrete." Lecture Notes in Civil Engineering , no. : 458-467.
Malaysia is among the countries that have abundant reserves of raw material to be used to form metakaolin (MK). Only a few studies are available in the literature, which examines the potential of the development of metakaolin through calcination and its use as supplementary cementitious material (SCM). The use of MK as SCM is essential to utilise the local resources and to reduce the carbon footprint and embodied energy in the use of cement. Thus, MK developed at laboratory scale, produced through using local source, is compared with the commercially available micro-silica by investigating their properties in this paper. The concrete made of MK and micro-silica was tested under compression, split tension and bending. The comparison of the phase difference between MK and micro-silica had carried out through X-ray diffraction pattern. Besides, an interfacial transition zone of concrete made of MK and micro-silica had observed through field emission scanning electron microscopy. A total of three mixes of concrete had prepared, out of which one was without cement replacement and served as control mix. The remaining two mixes were 10% cement replacement with micro-silica and MK. The results showed that MK has high reactivity with portlandite in concrete due to its irregular structure and the amorphous phase. The compressive strength was 4% higher with MK as compared to micro-silica at an early age. MK concrete displayed a higher split tensile strength of approximately 14% and 35% and a higher load-carrying capacity of approximately 15% compared to micro-silica and competitive with control concrete at ages 7–90 days.
Sadaqat Ullah Khan; Tehmina Ayub; Nasir Shafiq. Physical and Mechanical Properties of Concrete with Locally Produced Metakaolin and Micro-silica as Supplementary Cementitious Material. Iranian Journal of Science and Technology, Transactions of Civil Engineering 2020, 44, 1199 -1207.
AMA StyleSadaqat Ullah Khan, Tehmina Ayub, Nasir Shafiq. Physical and Mechanical Properties of Concrete with Locally Produced Metakaolin and Micro-silica as Supplementary Cementitious Material. Iranian Journal of Science and Technology, Transactions of Civil Engineering. 2020; 44 (4):1199-1207.
Chicago/Turabian StyleSadaqat Ullah Khan; Tehmina Ayub; Nasir Shafiq. 2020. "Physical and Mechanical Properties of Concrete with Locally Produced Metakaolin and Micro-silica as Supplementary Cementitious Material." Iranian Journal of Science and Technology, Transactions of Civil Engineering 44, no. 4: 1199-1207.
This paper presents a case study on the implementation of the construction and demolition waste management practices in the Malaysian construction sector. The scope was limited to the housing and high-rise buildings. Characterization of reuse and recycling potential was done using descriptive statistics. It is estimated that the waste generated by the housing sector is approximately 16% of the gross materials used, which is about 8.8 million tons/year, and 32% of such waste (approximately 2.8 million tons/year) has the potential for reuse and recycling. However, the high-rise building construction generates construction waste in a large quantity of more than 10 million tons/years (about 70% of the building construction waste), which shows a high potential for reusability and recycling. The reasons behind the low recycling potential for the construction and demolition (C&D) waste generates by the housing sector are found that its quality is low and contains some types of contaminants.
Usman Aminu Umar; Nasir Shafiq; Farah Amira Ahmad. A case study on the effective implementation of the reuse and recycling of construction & demolition waste management practices in Malaysia. Ain Shams Engineering Journal 2020, 12, 283 -291.
AMA StyleUsman Aminu Umar, Nasir Shafiq, Farah Amira Ahmad. A case study on the effective implementation of the reuse and recycling of construction & demolition waste management practices in Malaysia. Ain Shams Engineering Journal. 2020; 12 (1):283-291.
Chicago/Turabian StyleUsman Aminu Umar; Nasir Shafiq; Farah Amira Ahmad. 2020. "A case study on the effective implementation of the reuse and recycling of construction & demolition waste management practices in Malaysia." Ain Shams Engineering Journal 12, no. 1: 283-291.
This paper presents an experimental study on improving the post-cracking and the fracture behavior of engineered geopolymer composite containing polyvinyl alcohol (PVA) fibers. Two classes of fibers designated as coarse and fine were investigated. The single fiber volume governed the total number of fibers dispersed in the unit volume of the matrix (Nv), which caused significant effects on the post-cracking and the fracture behavior of the composite. The molarity of the NaOH solution is an important parameter that controlled the geopolymerization process and affected the strength and other properties of the composite. Three different molarity of NaOH solution, 8 M, 12 M, and 16 M, were investigated. The results showed that the specimens made of 8 M matrix containing fine fibers (0.04 mm diameter and 8 mm and 12 mm in length) performed well in the post-cracking stage and satisfied the criteria for pseudo strain hardening (PSH). The direct tensile strength results showed that 8 mm and 12 mm long fine fibers in the 8 M matrix achieved the strength ratio of ultimate to the first crack strength as 1.7 and 1.66, respectively. The strength ratio criterion for PSH suggested a value greater than 1.3. Similarly, from the notched-beam bending test, the energy performance index of 8 mm, and 12 mm long fine fibers in the 8 M matrix were estimated as 7.77 and 6.52, respectively. In contrast, a value of greater than 3 is recommended for PSH behavior. Fine fibers added in the 12 M and 16 M matrix also satisfied the criteria for PSH behavior. Whereas, the coarse fibers (0.2 mm diameter and 18 mm and 24 mm in length) performed well in resisting direct compression and showed higher fracture energy and the modulus of elasticity. The best combination was observed as a 12 M matrix containing fine fibers of 0.04 mm diameter and 8 mm in length.
Muhammad Zahid; Nasir Shafiq; Siti Nooriza A. Razak; Rana Faisal Tufail. Investigating the effects of NaOH molarity and the geometry of PVA fibers on the post-cracking and the fracture behavior of engineered geopolymer composite. Construction and Building Materials 2020, 265, 120295 .
AMA StyleMuhammad Zahid, Nasir Shafiq, Siti Nooriza A. Razak, Rana Faisal Tufail. Investigating the effects of NaOH molarity and the geometry of PVA fibers on the post-cracking and the fracture behavior of engineered geopolymer composite. Construction and Building Materials. 2020; 265 ():120295.
Chicago/Turabian StyleMuhammad Zahid; Nasir Shafiq; Siti Nooriza A. Razak; Rana Faisal Tufail. 2020. "Investigating the effects of NaOH molarity and the geometry of PVA fibers on the post-cracking and the fracture behavior of engineered geopolymer composite." Construction and Building Materials 265, no. : 120295.
Increasing attention was given to building information modeling (BIM) and multi-criteria decision-making (MCDM) globally due to their advantages for various stages of the life cycle of a building. The aim of this paper is to improve practitioners' understanding of the process for BIM and MCDM adoption towards sustainable construction through energy efficiency. A questionnaire survey is being conducted for construction professionals and building industry experts in Malaysia. With expert survey data, a multi-criteria decision model using analytical network process (ANP) was built to identify key factors affecting sustainable building by reducing both embodied and operational energy and carbon emissions. Data from the survey was analysed using descriptive statistics. Model developed consisted of three clusters with a total of six nodes, and the level of importance was compared pairwise with one another. Results shows that design optimisation, reduced material requirements are important factors for sustainable construction considered in the BIM application.
Abdulrahman Haruna; Nasir Shafiq; O.A. Montasir. Building information modelling application for developing sustainable building (Multi criteria decision making approach). Ain Shams Engineering Journal 2020, 12, 293 -302.
AMA StyleAbdulrahman Haruna, Nasir Shafiq, O.A. Montasir. Building information modelling application for developing sustainable building (Multi criteria decision making approach). Ain Shams Engineering Journal. 2020; 12 (1):293-302.
Chicago/Turabian StyleAbdulrahman Haruna; Nasir Shafiq; O.A. Montasir. 2020. "Building information modelling application for developing sustainable building (Multi criteria decision making approach)." Ain Shams Engineering Journal 12, no. 1: 293-302.
The concrete-filled double skin steel tube (CFDST) is a more viable option compared to a concrete-filled steel tube (CFST) due to consisting a hollow section, while degradation is enhanced simply by using carbon fiber-reinforced polymer (CFRP). Hence, the stabilization of a concrete’s ductile strength needs high- performance fiber-reinforced cementitious conmposite. This study investigates the behavior of high-performance fiber-reinforced cementitious composite-filled double-skin steel tube (HPCFDST) beams strengthened longitudinally with various layers, lengths, and configurtion of CFRP sheets. The findings showed that, with increased CFRP layers, the moment capacity and flexural stiffness values of the retrofitted HPCFDST beams have significantly improved. For an instant, the moment capacity of HPCFDST beams improved by approximately 28.5% and 32.6% when they were wrapped partially along 100% with two and three layers, respectively, compared to the control beam. Moreover, the moment capacity of the HPCFDST beam using two partial layers of CFRP along 75% of its sufficient length was closed to the findings of the beam with two full CFRP layers. For energy absorption, the results showed a vast disparity. Only the two layers with a 100% full length and partial wrapping showed increasing performance over the control. Furthermore, the typical failure mode of HPCFDST beams was observed to be local buckling at the top surface near the point of loading and CFRP rapture at the bottom of effect length.
Ahmed Al-Nini; Ehsan Nikbakht; Agusril Syamsir; Nasir Shafiq; Bashar S. Mohammed; Amin Al-Fakih; Waleed Al-Nini; Y. H. Mugahed Amran. Flexural Behavior of Double-Skin Steel Tube Beams Filled with Fiber-Reinforced Cementitious Composite and Strengthened with CFRP Sheets. Materials 2020, 13, 3064 .
AMA StyleAhmed Al-Nini, Ehsan Nikbakht, Agusril Syamsir, Nasir Shafiq, Bashar S. Mohammed, Amin Al-Fakih, Waleed Al-Nini, Y. H. Mugahed Amran. Flexural Behavior of Double-Skin Steel Tube Beams Filled with Fiber-Reinforced Cementitious Composite and Strengthened with CFRP Sheets. Materials. 2020; 13 (14):3064.
Chicago/Turabian StyleAhmed Al-Nini; Ehsan Nikbakht; Agusril Syamsir; Nasir Shafiq; Bashar S. Mohammed; Amin Al-Fakih; Waleed Al-Nini; Y. H. Mugahed Amran. 2020. "Flexural Behavior of Double-Skin Steel Tube Beams Filled with Fiber-Reinforced Cementitious Composite and Strengthened with CFRP Sheets." Materials 13, no. 14: 3064.
This paper presents the experimental analysis of the effects of simulated hydrocarbon fire exposure on the mechanical properties and the heat transmission in fiber-reinforced self-compacting concrete, FR-SCC. For that purpose, 300-mm thick, and 1200-mm square-shaped slabs were cast. Basalt and polyvinyl alcohol (PVA) fibers were added using the content of 1, 1.5, and 2% in self-compacting concrete. For investigating the heat transmission within 300-mm thick slabs, five external thermocouples were installed at the unexposed face to the fire of the slabs. Similarly, eleven internal thermocouples were installed at an interval of 25 mm throughout the slab thickness. It has been found that fibers have shown better insulation than the controlled concrete; the unexposed to fire surface of FR-SCC showed temperatures lower by ten degree Celcius than the controlled concrete. Compressive strength results showed that fiber addition caused a higher reduction in strength because of softening and stiffness reduction due to high-temperature exposure. After 120 min of fire exposure, basalt fibers caused an average reduction of 30% in the compressive strength, and PVA fibers caused an average reduction of 25%. Whereas, the addition of fibers improved the split cylindrical tensile strength even after exposure to 120 min of fire exposure in comparison with the unreinforced samples.
Noraniza Mohammad Jani; Mohammad Shakir Nasif; Nasir Shafiq; Ian Holt. Experimental Investigation on the Effect of Varying Fiber Mix Proportion on the Mechanical and Thermal Performances of Fiber-Reinforced Self-Compacting Concrete under Hydrocarbon Fire Condition. Applied Sciences 2020, 10, 4586 .
AMA StyleNoraniza Mohammad Jani, Mohammad Shakir Nasif, Nasir Shafiq, Ian Holt. Experimental Investigation on the Effect of Varying Fiber Mix Proportion on the Mechanical and Thermal Performances of Fiber-Reinforced Self-Compacting Concrete under Hydrocarbon Fire Condition. Applied Sciences. 2020; 10 (13):4586.
Chicago/Turabian StyleNoraniza Mohammad Jani; Mohammad Shakir Nasif; Nasir Shafiq; Ian Holt. 2020. "Experimental Investigation on the Effect of Varying Fiber Mix Proportion on the Mechanical and Thermal Performances of Fiber-Reinforced Self-Compacting Concrete under Hydrocarbon Fire Condition." Applied Sciences 10, no. 13: 4586.
The concept of a sustainable environment generally refers to the development that creates a balance between the resources consumption pattern and the rate of depletion of natural resources. For determining the level of sustainability of any project, three types of impacts are assessed: economic, environmental, and social. This paper presents an analytical study that focused on establishing a correlation of eco-efficiency index for low-rise reinforced concrete residential housing in Malaysia. A statistical technique using the response surface method was performed, with the help of design expert software. The data was verified using regression analysis and represented by R2 value, standard deviation, and coefficient of variation. By using economic factors, environmental factors, and the eco-efficiency index, 3D model graphs were developed for structural concrete containing fly ash, and blast furnace slag (BFS), which was assigned to the structural members in a single and double story housing. The study has concluded that the correlations established between the cost and carbon emission, economic & environmental scores, and the eco-efficiency index have shown a linear trend for single story housing and a cubic for the double story housing.
Mohd Samsudin Abdul Hamid; Nasir Shafiq; Osamah Kiwan. Establishing the Correlations for Eco-Efficiency Index of Various Types of Structural Concrete Used in the Malaysian Housing Using Response Surface Method. Applied Sciences 2020, 10, 4372 .
AMA StyleMohd Samsudin Abdul Hamid, Nasir Shafiq, Osamah Kiwan. Establishing the Correlations for Eco-Efficiency Index of Various Types of Structural Concrete Used in the Malaysian Housing Using Response Surface Method. Applied Sciences. 2020; 10 (12):4372.
Chicago/Turabian StyleMohd Samsudin Abdul Hamid; Nasir Shafiq; Osamah Kiwan. 2020. "Establishing the Correlations for Eco-Efficiency Index of Various Types of Structural Concrete Used in the Malaysian Housing Using Response Surface Method." Applied Sciences 10, no. 12: 4372.
This paper presents the results of an experimental study that investigated the effects of two parameters: sand/fly ash (S/FA) ratio and water to geopolymer-solid (W/GS) ratio on the engineered geopolymer composite. The trial mix designs were optimized using the response surface method. These parameters influence the properties of the fresh and hardened geopolymer matrix, such as slump flow, compressive strength, flexural strength, elastic modulus, flexural toughness, ductility index and drying shrinkage. The optimizing process was conducted by developing statistical models using the response surface methodology (RSM) technique. The developed models were statistically validated and could be used to determine the desired response of engineered geopolymer composite (EGC) with a significance level of more than 95%. In this study, the optimized values of the S/FA ratio and W/GS ratio were obtained as 0.341701 and 0.225184, respectively. To validate the optimized S/FA ratio and W/GS ratio, an experimental study was performed, and a difference of less than 5% was found between predicted and experimental results.
Muhammad Zahid; Nasir Shafiq. Effects of Sand/Fly Ash and the Water/Solid Ratio on the Mechanical Properties of Engineered Geopolymer Composite and Mix Design Optimization. Minerals 2020, 10, 333 .
AMA StyleMuhammad Zahid, Nasir Shafiq. Effects of Sand/Fly Ash and the Water/Solid Ratio on the Mechanical Properties of Engineered Geopolymer Composite and Mix Design Optimization. Minerals. 2020; 10 (4):333.
Chicago/Turabian StyleMuhammad Zahid; Nasir Shafiq. 2020. "Effects of Sand/Fly Ash and the Water/Solid Ratio on the Mechanical Properties of Engineered Geopolymer Composite and Mix Design Optimization." Minerals 10, no. 4: 333.
Palm oil mill effluent (POME) is a highly polluted wastewater that consists of a high organic content of 4–5% total solids; a potential renewable energy source. A waste to energy study was conducted to improve biogas production using POME as substrate by ultrasonication pretreatment at mesophilic temperatures. The effect of temperature on the specific growth rate of anaerobes and methanogenic activity was investigated. Five sets of assays were carried out at operating temperatures between 25 °C and 45 °C. Each set consisted of two experiments using identical anaerobic sequencing batch reactors (AnSBR); fed with raw POME (control) and sonicated POME, respectively. The ultrasonication was set at 16.2 min ultrasonication time and 0.88 W mL−1 ultrasonication density with substrate total solids concentration of 6% (w/v). At 25 °C, biogas production rate and organic matter removal exhibited lowest values for both reactors. The maximum organic degradation was 96% from AnSBR operated at 30 °C fed with sonicated POME and 91% from AnSBR operated at 35 °C fed with unsonicated POME. In addition, the methane yield from AnSBR operated at 30 °C was enhanced by 21.5% after ultrasonication pretreatment. A few normality tests and a t-test were carried out. Both tests indicated that the residuals of the experimental data were normality distributed with mean equals to zero. The results demonstrated that ultrasonication treatment was a promising pretreatment to positively affect the organic degradation and biogas production rates at 30–35 °C.
Mohamed Hasnain Isa; Lai-Peng Wong; Mohammed J.K. Bashir; Nasir Shafiq; Shamsul Rahman Mohamed Kutty; Izharul Haq Farooqi; How Chinh Lee. Improved anaerobic digestion of palm oil mill effluent and biogas production by ultrasonication pretreatment. Science of The Total Environment 2020, 722, 137833 .
AMA StyleMohamed Hasnain Isa, Lai-Peng Wong, Mohammed J.K. Bashir, Nasir Shafiq, Shamsul Rahman Mohamed Kutty, Izharul Haq Farooqi, How Chinh Lee. Improved anaerobic digestion of palm oil mill effluent and biogas production by ultrasonication pretreatment. Science of The Total Environment. 2020; 722 ():137833.
Chicago/Turabian StyleMohamed Hasnain Isa; Lai-Peng Wong; Mohammed J.K. Bashir; Nasir Shafiq; Shamsul Rahman Mohamed Kutty; Izharul Haq Farooqi; How Chinh Lee. 2020. "Improved anaerobic digestion of palm oil mill effluent and biogas production by ultrasonication pretreatment." Science of The Total Environment 722, no. : 137833.
In selecting the binder composition for oil well application, its stability is an important design parameter. This paper presents the results of an experimental study conducted for comparing the linear expansion characteristics of geopolymer cement with the traditionally used ASTM Class G cement system. The expansion test was done in a water bath at 60 °C subjected to different curing intervals. The linear expansion of a cement system defines as the dimensional changes occur in the system, which is sometimes required to avoid the cement shrinkage during the hydration phase. In the case when the desired level of expansion is not achieved in the system, then the commercially available expandable materials are added in the class G cement system that enables the system to expand to the desired level. Shrinkage in the cementing system causes the formation of a microannulus or induces a gap that may allow the migration of fluid, hence the integrity of the system could be lost. This experimental study has revealed that the geopolymer cement tends to expand 0.15%–0.2% without the addition of any admixture, whereas the ASTM Class G cement has shown a lower value of linear expansion, which was obtained less than 0.1% after 18 days of curing. In the case of Class G cement, the addition of expandable material helped to increase the expansion; in the case of a geopolymer system, the additive has further accelerated the expansion.
Siti Humairah Bt Abd Rahman; Sonny Irawan; Nasir Shafiq; Raja Rajeswary. Investigating the expansion characteristics of geopolymer cement samples in a water bath and compared with the expansion of ASTM Class-G cement. Heliyon 2020, 6, e03478 .
AMA StyleSiti Humairah Bt Abd Rahman, Sonny Irawan, Nasir Shafiq, Raja Rajeswary. Investigating the expansion characteristics of geopolymer cement samples in a water bath and compared with the expansion of ASTM Class-G cement. Heliyon. 2020; 6 (2):e03478.
Chicago/Turabian StyleSiti Humairah Bt Abd Rahman; Sonny Irawan; Nasir Shafiq; Raja Rajeswary. 2020. "Investigating the expansion characteristics of geopolymer cement samples in a water bath and compared with the expansion of ASTM Class-G cement." Heliyon 6, no. 2: e03478.
An estimate shows that approximately 50% of global annual construction activities account for the repair and retrofitting of structures and constructed facilities. Therefore, structural rehabilitation and repair are becoming hot topics among researchers, in order to find innovative and comprehensive solutions. Ultra-high-performance concrete (UHPC) is designed to achieve high strength and long-term durability. Such types of concrete offer a solution for complicated repair and retrofitting jobs. Although many benefits of using UHPC have been derived, many concerns have also been identified with the use of UHPC—sustainability is considered a critical concern due to the requirement of large proportions of cement, which results in an increase in cost and environmental impacts. This paper presents a recipe for UHPC that contains a small ratio of cement and a large proportion of fly ash, i.e., up to 50%, as a cement replacement material (CRM). In order to achieve long-term durability and increase bonding with old concrete or brickwork for repair and retrofitting purposes, ultra-fine calcium carbonate (UFCC) is also added. In selecting an appropriate material for structural repair, it is essential to acquire an understanding of the material behavior. Therefore, this research was focused on providing a comprehensive guide to the behavior and strength performance of UHPC. The experimental results have shown that the highest strength of UHPC with low cement content can be achieved using a binary combination of high-volume fly ash (HVFA) and ultra-fine CaCO3 (UFCC) as a substitution for cement by up to a ratio of 50% in the recipe. The UHPC with low cement content displayed excellent repair and retrofitting potential for structural strengthening in regions of high stress by developing a strong bond with the existing concrete substrate.
Norzaireen M. Azmee; Nasir Shafiq. Investigating the Impacts of Ultra-Fine Calcium Carbonate in High-Volume Fly Ash Concrete for Structural Rehabilitation for Sustainable Development. Sustainability 2019, 11, 4671 .
AMA StyleNorzaireen M. Azmee, Nasir Shafiq. Investigating the Impacts of Ultra-Fine Calcium Carbonate in High-Volume Fly Ash Concrete for Structural Rehabilitation for Sustainable Development. Sustainability. 2019; 11 (17):4671.
Chicago/Turabian StyleNorzaireen M. Azmee; Nasir Shafiq. 2019. "Investigating the Impacts of Ultra-Fine Calcium Carbonate in High-Volume Fly Ash Concrete for Structural Rehabilitation for Sustainable Development." Sustainability 11, no. 17: 4671.
This paper discussed the effects of modified metakaolin (MK) with nano-silica (NS) on the mechanical properties and durability of concrete. In the first phase, trial mixes of concrete were prepared for achieving the desired value of the 28 days compressive strength, and the charge passed in rapid chloride permeability test (RCPT). In the second phase, statistical analysis was performed on the experimental results using the response surface method (RSM). The RSM was applied for optimizing the mix proportions for the required performance by exploiting the relationship between the mix characteristics and the corresponding test results. A blend of 10% MK + 1% NS as part of cement replacement exhibited the highest mechanical properties and durability characteristics of concrete; concrete mix showed that the 28-days compressive strength (CS) was 103 MPa, which was 15% greater than the CS of the control mix without MK or NS. The same mix showed more than 40% higher flexural and split-tensile strength than the control mix; also it resulted in a reduction of 73% in the rapid chloride permeability value. ANOVA technique was used for optimizing the nano-silica and metakaolin content for achieving maximum compressive strength and minimum RCPT value. Statistical analysis using ANOVA technique showed that the maximum compressive strength and lowest RCPT value could be achieved with a blend of 10% MK and 1.55% NS.
Nasir Shafiq; Rabinder Kumar; Muhammad Zahid; Rana Faisal Tufail. Effects of Modified Metakaolin Using Nano-Silica on the Mechanical Properties and Durability of Concrete. Materials 2019, 12, 2291 .
AMA StyleNasir Shafiq, Rabinder Kumar, Muhammad Zahid, Rana Faisal Tufail. Effects of Modified Metakaolin Using Nano-Silica on the Mechanical Properties and Durability of Concrete. Materials. 2019; 12 (14):2291.
Chicago/Turabian StyleNasir Shafiq; Rabinder Kumar; Muhammad Zahid; Rana Faisal Tufail. 2019. "Effects of Modified Metakaolin Using Nano-Silica on the Mechanical Properties and Durability of Concrete." Materials 12, no. 14: 2291.