Khairul Azwan Ismail
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Preferred name
Khairul Azwan Ismail
Official Name
Ismail, Khairul Azwan
Alternative Name
Khairul Azwan, Ismail
Khirul Azwan, Ismail
IsmailIsmail, Khairul Azwan
Ismail, K. A.
Main Affiliation
Scopus Author ID
57200855539
Researcher ID
B-3707-2015

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Mechanical and microstructural evaluations of lightweight aggregate geopolymer concrete before and after exposed to elevated temperatures

2013 , Omar Abdulkareem , Mohd. Mustafa Al Bakri Abdullah , Kamarudin Hussin , Khairul Azwan Ismail , Mohammed Binhussain

This paper presents the mechanical and microstructural characteristics of a lightweight aggregate geopolymer concrete (LWAGC) synthesized by the alkali-activation of a fly ash source (FA) before and after being exposed to elevated temperatures, ranging from 100 to 800 °C. The results show that the LWAGC unexposed to the elevated temperatures possesses a good strength-to-weight ratio compared with other LWAGCs available in the published literature. The unexposed LWAGC also shows an excellent strength development versus aging times, up to 365 days. For the exposed LWAGC to the elevated temperatures of 100 to 800 °C, the results illustrate that the concretes gain compressive strength after being exposed to elevated temperatures of 100, 200 and 300 °C. Afterward, the strength of the LWAGC started to deteriorate and decrease after being exposed to elevated temperatures of 400 °C, and up to 800 °C. Based on the mechanical strength results of the exposed LWAGCs to elevated temperatures of 100 °C to 800 °C, the relationship between the exposure temperature and the obtained residual compressive strength is statistically analyzed and achieved. In addition, the microstructure investigation of the unexposed LWAGC shows a good bonding between aggregate and mortar at the interface transition zone (ITZ). However, this bonding is subjected to deterioration as the LWAGC is exposed to elevated temperatures of 400, 600 and 800 °C by increasing the microcrack content and swelling of the unreacted silicates.

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Publication

Mechanical and microstructural evaluations of lightweight aggregate geopolymer concrete before and after exposed to elevated temperatures

2013 , Omar Abdulkareem , Mohd Abdullah , Kamarudin Hussin , Khairul Ismail , Mohammed Binhussain

This paper presents the mechanical and microstructural characteristics of a lightweight aggregate geopolymer concrete (LWAGC) synthesized by the alkali-activation of a fly ash source (FA) before and after being exposed to elevated temperatures, ranging from 100 to 800 °C. The results show that the LWAGC unexposed to the elevated temperatures possesses a good strength-to-weight ratio compared with other LWAGCs available in the published literature. The unexposed LWAGC also shows an excellent strength development versus aging times, up to 365 days. For the exposed LWAGC to the elevated temperatures of 100 to 800 °C, the results illustrate that the concretes gain compressive strength after being exposed to elevated temperatures of 100, 200 and 300 °C. Afterward, the strength of the LWAGC started to deteriorate and decrease after being exposed to elevated temperatures of 400 °C, and up to 800 °C. Based on the mechanical strength results of the exposed LWAGCs to elevated temperatures of 100 °C to 800 °C, the relationship between the exposure temperature and the obtained residual compressive strength is statistically analyzed and achieved. In addition, the microstructure investigation of the unexposed LWAGC shows a good bonding between aggregate and mortar at the interface transition zone (ITZ). However, this bonding is subjected to deterioration as the LWAGC is exposed to elevated temperatures of 400, 600 and 800 °C by increasing the microcrack content and swelling of the unreacted silicates.

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Energy absorption and failure behavior of Al/CFRP/GFRP hybrid tubes under quasi-static axial loading

2023-07-01 , Fauziah Che Mat , Mohd Ridzuan Mohd Jamir , Masniezam Ahmad , Mohd Shukry Abdul Majid , Khairul Azwan Ismail

Fiber metal laminate (FML) is gaining increased interest among researchers in designing thin-walled tubes as an efficient energy absorber. The combination of aluminum tube and fiber-reinforced polymer (FRP) as an FML hybrid tube has successfully demonstrated enhanced crashworthiness performance of structures. Previous studies reported FML hybrid tubes employing a single type of FRP composite material as the laminate material. Investigations on the effect of stacking sequences of multiple types of FRP composite as laminate materials are limited and mostly focused on sandwich structures. This study aims to investigate the effect of reinforcement material as a laminate layer and stacking sequences on the crashworthiness characteristics of aluminum-FRP hybrid tubes under quasi-static axial compression loading. The crashworthiness characteristics and the failure behavior of aluminum monolithic tube, aluminum-single FRP material, and aluminum-multi FRP material hybrid tubes are tested and compared. Glass FRP (GFRP) demonstrates great potential as a laminate material for aluminum tube compared with carbon FRP (CFRP). Aluminum-GFRP and aluminum-GFRP-CFRP hybrid tubes exhibit a 26.4 % and 66.9 % increase in energy absorbed, respectively, compared with the monolithic aluminum tube. The specific energy absorption and crushing force efficiency of the aluminum-GFRP-CFRP hybrid tube show minimal reductions of 4.9 % and 6.2 %, respectively. GFRP is the better choice of laminate material for aluminum tubes compared with CFRP. Multiple FRP laminates show a larger crashworthiness enhancement of FRP hybrid tubes in achieving better crashworthiness performance of the energy absorber. These findings imply that the selection and stacking sequences of laminate material are vital in tailoring the performance of the hybrid tubes toward efficient energy absorbers.

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Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to produce lightweight aggregate-based geopolymer

2015 , Rafiza Razak , Mohd Abdullah , Kamarudin Hussin , Khairul Ismail , Djwantoro Hardjito , Zarina Yahya

This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

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Cloud-based System for University Laboratories Air Monitoring

2020-09-21 , Abu Hassan Abdullah , Sukhairi Sudin , Mustafa M.H. , Fathinul Syahir Ahmad Sa'ad , Khairul Azwan Ismail , Muhammad Aizat Abu Bakar , Mohamed Elshaikh Elobaid Said Ahmed , Abdul Ghapar Ahmad , Zahari Awang Ahmad , Sara Yasina Yusuf

Indoor air such as house, shopping complex, hospital, university, office and hotel should be monitor for human safety and wellbeing. These closed areas are prone to harmful air pollutants i.e. allergens, smoke, mold, particles radon and hazardous gas. Laboratories in university are special room in which workers (student, technician, teaching/research assistants, researcher and lecturer) conduct their works and experiment. The activities and the environment will generate specific air pollutant which concentration depending to their parameters. Anyone in the environment that exposure to these pollutants may affect safety and health issue. This paper proposes a study of development of a cloud-based electronic nose system for university laboratories air monitoring. The system consists of DSP33-based electronic nose (e-nose) as nodes which measure main indoor air pollutant along with two thermal comfort variables, temperature and relative humidity. The e-noses are placed at five different laboratories for acquiring data in real time. The data will be sent to a web server and the cloud-based system will process, analyse using Neuro-Fuzzy classifier and display on a website in real time. The system will monitor the laboratories air pollutants and thermal comfort by predict the pollutant concentration and dispersion in the area i.e. Air Pollution Index (API). In case of air hazard safety (e.g., gas spills detection and pollution monitoring), the system will alert the security by activate an alarm and through e-mail. The website will display the API of the area in real-time. Results show that the system performance is good and can be used to monitor the air pollutant in the university laboratories.

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Optimization of NaOH molarity, LUSI mud/alkaline activator, and Na₂SiO₃/NaOH ratio to produce lightweight aggregate-based geopolymer

2015 , Rafiza Abd Razak , Mohd. Mustafa Al Bakri Abdullah , Djwantoro Hardjito , Kamarudin Hussin , Khairul Azwan Ismail , Zarina Yahya

This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na₂SiO₃/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

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