Conference Publications

;

Iqmal Tahir

Effects of methyl methacrylate on the properties of chitosan-filled polypropylene (PP) composites has been investigated. Mechanical and thermal properties of the composites were analyzed according to ASTM D 638-91, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). The results showed that tensile strength of PP composites decreased upon the addition of chitosan, while Young's modulus improved. At a similar filler loading, the treated PP/chitosan composites were found to have higher tensile strength and Young's modulus as compared with the untreated composites. Thermal analysis results showed that thermal stability and crystallinity of the treated composites were higher than the untreated ones. Scanning electron microscopy (SEM) and Fourier transforms infrared (FTIR) studies revealed less detached filler from matrix on tensile surface of the treated composites as an evidence of enhanced filler-matrix interfacial adhesion due to formation of ester-bridge between the chitosan and the methyl methacrylate.

Publication

Effect of Glass Reinforced Epoxy (GRE) pipe filled with geopolymer materials for piping application: compression properties

( 2016)

Mohammad Firdaus Abu Hashim

;

;

Che Mohd Ruzaidi Ghazali

;

;

Mohammed Binhussain

;

Mohd Firdaus Omar

The aim of this paper is to achieve the highest compressive strength of glass reinforced epoxy pipe with the geopolymer filler content of weight percentage that were used in glass reinforced epoxy pipe. The samples were prepared by using the filament winding method. The effect of weight percentage of geopolymer materials in epoxy hardener was studied under mechanical testing, which is using the compression test. A series of glass reinforced epoxy pipe and glass reinforced epoxy pipe filled with 10 – 40 weight percentage geopolymer filler which is white clay were prepared. The compression strength of the glass reinforced epoxy pipe filled geopolymer materials is determined using Instron Universal Testing under compression mode. It was found that compressive strength for samples with white clay geopolymer filler are much higher compare to glass reinforced epoxy pipe without geopolymer filler. Moreover, the compressive strength of glass reinforced epoxy pipe filled with white clay geopolymer filler was increased from 10 wt% to 30 wt% of geopolymer content. However, the compressive strength of glass reinforced epoxy pipe with white clay geopolymer filler suddenly decreased when added to 40 wt%. The results indicated that the blending of geopolymer materials in epoxy system can be obtained in this study.

Publication

Manufacturing of fire resistance geopolymer: a review

( 2016)

Ikmal Hakem Aziz

;

;

Heah Cheng Yong

;

;

;

Aeslina Abdul Kadir

;

Emy Aizat Azimi

Protection against fire using inorganic polymer is a new application of engineering technology. Even though, there are varieties of fire-protection materials, there is always a need for the development of new materials with improved thermophysical properties and low cost. Geopolymer composites materials are promising from this point of view. Granulated blast furnace slag, boiler ash and fly ash have been used as the prime materials for forming geopolymers composites. Geopolymers have been studied due to its unique properties such as a good fire resistance. Geopolymer offers an innovative for application associated with the high thermal application. This paper summarizes on the potential of alkaliactivated materials over the past decades along with outlines of the manufacturing of geopolymer composites for fire resistance application.

7 17

Publication

Effect of crumb rubber on compressive strength of fly ash based geopolymer concrete

( 2016)

Ahmad Azrem Azmi

;

;

Che Mohd Ruzaidi Ghazali

;

Andrei Victor Sandu

;

This study explores the effect of different percentage of crumb rubber on compressive strength of fly ash based geopolymer concrete. This research attempted to produce rubberized geopolymer concrete as an environmentally friendly, lightweight and durable product. Crumb rubber with ranged size from 73 μm to 375 μm was used in order to replace fine aggregates in geopolymer concrete. The replacements of crumb rubber were 0%, 5%, 10%, 15% and 20% in the fly ash based geopolymer concrete. The ratio of fly ash to alkaline activator was 2.5 and the ratio of Na2SiO3 to NaOH was fixed at 2.0. After the curing process, the strengths of the samples were tested on days 7 and 28. The results show that there is a reduction in all compressive strength for crumb rubber mixture, but still higher than normal rubberized concrete. Rubberized geopolymer concrete is a suitable solution in some non structural applications.

1 7

Publication

Kaolin geopolymer as precursor to ceramic formation

( 2016)

Nur Ain Jaya

;

;

Che Mohd Ruzaidi Ghazali

;

Mohammed Hussain

;

;

Romisuhani Ahmad

This paper introduced the potential application of kaolin geopolymer as ceramic precursor. This is one of the alternatives to produce high strength ceramic at a slightly lower temperature. Upon sintering the conversion of geopolymer to ceramic occur. The kaolin used were characterized using XRF and has plate-like structure upon investigating through microstructural analysis. Geopolymer mixture is produced using 12 M NaOH molarity with the Na2SiO3/NaOH ratio of 0.24. The sintering temperature used were ranging from 900 °C to 1200 °C. The flexural strength showed the highest value of 88.47 MPa when sintered at 1200 °C. The combination of geopolymerization and sintering has attributed to the strength increment as temperature increased. The density is observed to increase with increasing sintering temperature due to the appearance of the close pores in the structure. Sintering of the geopolymer resulted in the formation of liquid phase, which enables the joining of particles to produce dense microstructure.

1 12

Publication

Morphology and properties of geopolymer coatings on glass Fibre-Reinforced Epoxy (GRE) pipe

( 2016)

Noor Fifinatasha Shahedan

;

;

Che Mohd Ruzaidi Ghazali

;

Mohammed Binhussain

;

Mohammed Al Husaini

;

;

Shamala Ramasamy

Geopolymer coatings were coated on glass fibre-reinforced epoxy (GRE) pipe by using kaolin, white clay and silica sand as source materials and sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as alkaline solution. The microstructure and mechanical property of geopolymer coating on GRE pipe were methodically investigated through morphology analysis, and flexural strength test. The result indicates the microstructure and interfacial layer between geopolymer coating and GRE pipe significantly influence the mechanical property of geopolymer coating. However, different source materials gave different microstructure and property in geopolymer coating.

2 9

Publication

Properties and behavior of geopolymer concrete subjected to explosive air blast loading: a review

( 2017)

Nurul Aida Mohd Mortar

;

;

Rafiza Abdul Razak

;

;

Ahmad Humaizi Hilmi

;

Andrei Victor Sandu

The severe damage to civilian buildings, public area, jet aircraft impact and defense target under explosive blast loading can cause a huge property loss. Most of researcher discusses the topics on design the concrete material model to sustain againts the explosive detonation. The implementation of modern reinforcement steels and fibres in ordinary Portland cement (OPC) concrete matrix can reduce the extreme loading effects. However, most researchers have proved that geopolymer concrete (GPC) has better mechanical properties towards high performance concrete, compared to OPC. GPC has the high early compressive strength and high ability to resist the thermal energy from explosive detonation. In addition, OPC production is less environmental friendly than geopolymer cement. Geopolymer used can lead to environmental protection besides being improved in mechanical properties. Thus, this paper highlighted on an experimental, numerical and the analytical studies cause of the explosive detonation impact to concrete structures.

Publication

The effect of different ratio bottom ash and fly ash geopolymer brick on mechanical properties for non-loading application

( 2017)

Laila Mardiah Deraman

;

;

;

;

Wan Mastura Wan Ibrahim

;

Andrei Victor Sandu

This paper studies the finding of strength and water absorption of geopolymer bricks using bottom ash and fly ash as a geopolymer raw material for non-loading application with minimum strength. The study has been conducted to produce bottom ash and fly ash geopolymer bricks by varying the ratio of fly ash-to-bottom ash, solid-to-liquid and sodium silicate (Na2SiO3)-to-sodium hydroxide (NaOH) in the mixing process. The compressive strength range between 3.8-4.5 MPa was obtained due to the minimum strength of non-loading application with 70°C curing temperature within 24 hours at 7 days of ageing. The optimum ratio selected of bottom ash-to-fly ash, solid-to-liquid and Na2SiO3-to-NaOH are 1:2, 2.0 and 4.0 respectively. The water absorption result is closely related to the amount of bottom ash used in the mix design.

Publication

Review on various types of geopolymer materials with the environmental impact assessment

( 2017)

Hariz Zain

;

;

;

Nurliyana Ariffin

;

Ridho Bayuaji

The development of green technology in the construction industry since 10 years ago is something to be proud of Malaysia. Several alternative geopolymer materials were invented in Malaysia such as fly ash, POFA, kaolin, metakaolin, and dolomite based geopolymer materials to achieve sustainable development especially in the building and construction sector. Those alternative materials are very important to replace the application of OPC, which is said to be the main cause of global warming. A review on the content of the chemical differences with the environmental impact resulting from the production of geopolymer is carried out in this study. In conclusion, fly ash based geopolymer material showed the best performance in terms of aluminosilicate content and also it is the best practice in the environmental protection applications for the moment. However, when compared with the OPC, fly ash geopolymer concrete was still able to reduce the effects of global warming potentials, but it is rather gave a negative impact on some aspects of the environment such as abiotic depletions, human toxicity, freshwater ecotoxicity, terrestrial ecotoxicity and acidification.

1 7

Publication

Corrosion studies of fly ash and fly ash-slag based geopolymer

( 2017-06)

F F Zainal

;

S F M Amli

;

K Hussin

;

A Rahmat

;

M M A B Abdullah

This paper presents the results of corrosion studies between Fly Ash Geopolymer (FG) paste and Fly Ash-Slag Geopolymer (FSG) paste. Geopolymer was made from aluminosilicate inorganic polymers mixed with the alkaline activator in order to reduce the carbon dioxide (CO₂) to the ecosystem. Samples then were cured at 60ºC for 24 hours in the oven. Reinforcement bar is placed at the center of the paste. The samples were examined after 7, 14 and 28 days in terms of Open Circuit Potential (OCP) test, phase analysis and morphology analysis. The potential values regarding OCP test for FSG paste from 7 days until 28 days are 0.464 V, 0.474 V and 0.498 V more positive than FG paste which the potential values are 0.087 V, 0.133 V and 0.206 V respectively. From the Pourbaix diagram, all the potential values for FG paste and FSG paste were located in the same Fe₂O₃, passivity region. Passive layer which is the oxide form exists in this region to protect the reinforcement bar from corrosion agents. It can be proved from phase analysis results which iron oxide hydroxide (FeOOH), hematite (Fe₂O₃) and magnetite (Fe₃O₄) peaks exist. The differences of morphological structures of these pastes were observed by Scanning Electron Microscope (SEM). It shows that FSG paste had good corrosion resistance and low corrosion rate compared to FG paste.

2 7

Publication

Screening drug, alcohol and substance abuse the psychometric measures

( 2018)

Mohamad Hashim Othman

;

Huzili Hussin

;

;

N.S. Alias

Urinalysis was used in previous studies among higher institution students (n=16252) in Malaysia to answer the question of whether university students are involved in drug abuse. However, the use of urinalysis had faced some problems. The problems were related to human rights issues and the cost to perform the urinalysis was expensive and quite impossible to be implemented to a large population of university students. To overcome this problem, this study was conducted to examine the effectiveness of psychometric measures in screening drug, alcohol and substance abuse. The Substance Abuse Subtle Screening Inventory A2 (SASSI-A2) was used for this purpose. SASSI-A2 is a brief screening tool designed to identify individuals who have a high probability of having a substance use disorder, including both substance abuse and substance dependence. SASSI-A2 comprises of 72 items that are rated on a two point scale with response; true and false. SASSI-A2 was translated into Malay language and it was refined through a back-translation technique and focus group approach. Psychometric testing was undertaken on a sample of 750 university students from five public universities in Malaysia. All participants were aged between 19 and 20 years. Internal consistency coefficients were calculated for the total scale and its subscales. Chronbach's alpha obtained for SASSI-A2 was 0.72. This relatively high level of Chronbach's alpha showed relatively high level of reliability. The results demonstrated that the whole SASSI-A2 meets the fundamental measurement properties and can discriminate groups of higher institution students from high to low on the substance dependency variable. The accuracy of the test has been found to be unaffected by gender, ethnicity, age and years of education. Although more rigorous validation studies are needed, it is recommended that SASSI-A2 be considered for usage to higher institution students populations when a brief, objective, and accurate screening tool for chemical dependency is needed.

1 12

Publication

The effect of brief cognitive behavioural therapy group intervention on self esteem among drug users

( 2018)

Huzili Hussin

;

M.H. Othman

;

;

N. S. Alias

Self-esteem is related to the individuals understanding and accepting the existing character and attitude to themselves. Failure to understand and accept their own strengths and weaknesses and in the same time do not have the skills to cope with it will caused them to be classified in the group who have low levels of self esteem. The up and down in self esteem will seriously affect the person emotional development and their reasoning process. Thus, reforming self esteem is an important key to help the rehabilition of drug abuser. Therefore, the purpose of this study is to investigate the effects of Brief Group Cognitive Behavioural Therapy on self-esteem among drug users. The quasi experimental design with one treatment group and one control group and four measurements (Pre Test, Post 1, Post 2 and Post 3) were employed in this study. The sample of 108 drugs users was chosen using purposive sampling procedure. Data were collected using standardized psychometric instruments, including Internal Control Index (Patricia Duttweiler, 1984) and The Rosenberg Self-Esteem Scale and were analysed using descriptive analysis. The findings shows the intervention of group Brief Cognitive Behavioural Therapy CBT (B) are succeed in increasing self-esteem mean score compared to control group in different time interval. As a conclusion, self-esteem among the subjects can be enhanced with an intervention of proper and systematic therapy instead of unplanned therapy sessions

2 10

Publication

Effect of alkali concentration on fly ash geopolymers

( 2018)

Siti Fatimah Azzahran Abdullah

;

;

;

Heah Cheng Yong

;

Khairunnisa Zulkifly

;

This paper presents the effect of NaOH concentration on fly ash geopolymers with compressive up to 56 MPa at 12M. The physical and mechanical on fly ash geopolymer are investigated. Test results show that the compressive strength result complied with bulk density result whereby the higher the bulk density, the higher the strength. Thus, the lower water absorption and porosity due to the increasing of NaOH concentration.

1 8

Publication

Effect of sodium hydroxide molarity on physical, mechanical and thermal conductivity of metakaolin geopolymers

( 2018)

Nur Ain Jaya

;

;

;

Heah Cheng Yong

;

In the present work, the effect of different sodium hydroxide (NaOH) molarity (6M, 8M, 10M, 12M and 14M) on the physical, mechanical and thermal conductivity of metakaolin geopolymers (MkGPs) was investigated. Geopolymers were prepared by activating the metakaolin with a mixture of NaOH with sodium silicate (Na₂SiO₃). The products obtained were characterized after 28 days of curing. The density, porosity, compressive strength and thermal conductivity (TC) were determined. In general, the NaOH molarity has a significant effect on the compressive strength of the MkGPs. The highest compressive strength was 14.6 MPa achieved with 10M of NaOH solution. The thermal conductivity of MkGPs measured in this work was low in the range between 0.71-0.97 W/mK. NaOH molarity had a significant effect on compressive strength but a marginal effect on thermal conductivity of MkGPs. The thermal conductivity was mainly affected by the bulk density and thus the total porosity. The results showed that the geopolymer can be considered to be used as the thermal insulating material.

1 13

Publication

Perception of teacher on cooperative learning

( 2018)

Nur Salimah Alias

;

Huzili Hussin

;

Junainor Hassan

;

Nor Syamimi Mohamed Adnan

;

Mohamad Hashim Othman

;