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Al Khums, Libya

Johari M.A.M.,Universiti Sains Malaysia | Altwair N.M.,Universiti Sains Malaysia | Altwair N.M.,Al Merghab University | Hashim S.F.S.,Universiti Sains Malaysia
Advances in Cement Research | Year: 2013

The fracture and tensile characteristics of engineered cementitious composites (ECCs) containing palm oil fuel ash (POFA) have been investigated. POFA obtained from a palm oil mill was treated first by grinding and then by heat treatment. The treated POFA was then utilised to produce ECCs in combination with polyvinyl alcohol fibres with proportions of POFA ranging from 0 to 1.2 from the mass of cement. The performance of the POFA-ECCs was evaluated by means of matrix fracture and direct tensile tests. The experimental results indicate that the ECC mix containing POFA exhibits lower fracture toughness and fracture energy values than a mix without POFA. Nonetheless, the addition of POFA contributes to a greater pseudo-strain hardening index, in particular at higher POFA content. This reveals that the use of POFA should be helpful for achieving strain hardening behaviour. In addition, an increase in POFA content increases the tensile strain capacity of the ECC. Furthermore, the crack width of the ECC decreases significantly with an increase of POFA content. Thus, the overall findings exhibit that the POFA used brings about promising positive effects on the fracture and tensile characteristics of ECCs. Source


Benisa M.,Al Merghab University | Babic B.R.,University of Belgrade | Grbovic A.,University of Belgrade | Stefanovic Z.,University of Belgrade
FME Transactions | Year: 2014

To produce a new component there are a trial and error stage to obtain a part without defects, which strongly depends on operator's experience. At this stage, the experience of designer and manufacturers should give an important aid to reduce trials to realize the minimization of response time and cost with maximization of the product equality. Rubber pad forming highly improves the formability of the blank because the contact surfaces between the rigid die and the rubber pad is flexible. This method enables to produce sheet metal components with complex contour by relatively low cost because only one rigid die is required. However, in aerospace field, parts are produced in small sheet metal bending and small number of components. It means that it is not worthy for large investments in tools and process design. For these reasons, it is necessary to use FE simulation of manufacturing process during the conceptual design. © Faculty of Mechanical Engineering, Belgrade. Source


Altwair N.M.,Universiti Sains Malaysia | Altwair N.M.,Al Merghab University | Megat Johari M.A.,Universiti Sains Malaysia | Saiyid Hashim S.F.,Universiti Sains Malaysia
Construction and Building Materials | Year: 2012

The flexural performance of green engineered cementitious composites (ECCs) containing high volume of palm oil fuel ash (POFA) has been investigated. Three sets of ECC mixtures with water-binder ratios of 0.33, 0.36, and 0.38 were prepared, and for each set, the ECC mixtures were proportioned to have varying POFA contents of 0, 0.4, 0.8, and 1.2 from the mass of cement. The flexural performance was assessed after 3, 28, and 90 days of curing using the four-point bending test. The results suggest that there is a corresponding reduction in the first cracking strength and flexural strength of the ECC beams with the increase of water-binder ratios and POFA content. Nonetheless, higher water-binder ratio and higher POFA content was found to concomitantly improve the flexural deflection capacity, which indicates a superior deflection hardening behaviour. Furthermore, number of cracks was increased and crack width of the ECC was significantly reduced with an increase of POFA content. In addition, there are good correlations between flexural deflection capacity from the four-point bending test and tensile strain capacity from the uniaxial tensile test. © 2012 Elsevier Ltd. All rights reserved. Source


Zeyad A.M.,Universiti Sains Malaysia | Zeyad A.M.,Yemen University of Science and Technology | MEGAT JOHARI M.A.,Universiti Sains Malaysia | MUHAMAD BUNNORI N.,Universiti Sains Malaysia | And 3 more authors.
Advanced Materials Research | Year: 2013

Palm oil fuel ash obtained from palm oil mill was treated via screening, grinding and heating to improve its pozzolanic reactivity. The characteristics of the palm oil fuel ash before and after treatment were monitored to assess the changes in the properties of the palm oil fuel ash. The resulting ultrafine palm oil fuel ash was then utilized to produce high strength concrete by replacing the ordinary Portland cement at 0, 20, 40 and 60% on mass-for-mass basis. The results show that the treatment process undertaken reduces the particle size, diminishes the unburned carbon content, while at the same time increases the glassy phases. The utilization of the ultrafine palm oil fuel ash in high strength concrete was observed to improve workability especially at higher ultrafine palm oil fuel ash content. In addition, the long-term compressive strength of the high strength concrete was significantly increased with the ultrafine palm oil fuel ash inclusion. Further, the long-term rapid chloride permeability was significant reduced especially at higher ultrafine palm oil fuel ash content of 60%, which could be translated into superior durability performance. © (2013) Trans Tech Publications, Switzerland. Source


Altwair N.M.,Universiti Sains Malaysia | Altwair N.M.,Al Merghab University | Johari M.A.M.,Universiti Sains Malaysia | Hashim S.F.S.,Universiti Sains Malaysia
Advanced Materials Research | Year: 2013

The present paper is a part of an extensive study on green palm oil fuel ash engineered cementitious composites conducted at Universiti Sains Malaysia. It specifically investigates the effects of water-binder ratio (w/b) and palm oil fuel ash (POFA) on the drying shrinkage of engineered cementitious composites (ECCs). W/b values of 0.33, 0.36, and 0.38 were selected. ECC mixes were proportioned to have various ratios of POFA ranging from 0 to 1.2 from the mass of cement. The drying shrinkage measurements were taken at 4, 11, 18, 25, 57, and 90 days. The experimental results show that w/b has a significant effect on the drying shrinkage of the ECC mixtures. Drying shrinkage is remarkably reduced with a decrease in the w/b. The results also showed that drying shrinkage of the composites is considerably reduced when POFA is used in the matrix. The measured drying shrinkage strain at 90 days is only 920×10-6 με to 1216×10-6 με for ECC mixtures with high POFA content. The shrinkage strain of the ECC mixtures without POFA at 90 days is nearly 1597×10-6 με to 1910×10-6 με. © (2013) Trans Tech Publications, Switzerland. Source

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