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Rusbintardjo G.,Islamic University of Sultan Agung | Hainin M.R.,University of Technology Malaysia | Yusoff N.I.M.,National University of Malaysia
Construction and Building Materials | Year: 2013

This study was conducted to investigate the suitability of using oil palm fruit ash (OPFA) as a bitumen modifier. The OPFA was used to fulfil all bitumen modification requirements, as well as to take advantage of a waste by-product of the palm oil mill industry which could help to reduce environmental pollution. Twenty-four OPFA-modified bitumens (OPFA-MBs) were produced by the laboratory mixing of normal bitumen (80/100) from two sources with Fine and Coarse OPFAs of six different contents. This process was conducted at a mixing temperature of 160 C, a mixing time of 60 min and a mixing stirring speed of 800 rpm. The consistency and rheological characteristics of the OPFA-MBs were analysed by means of conventional as well as dynamic mechanical analysis using dynamic shear rheometer (DSR), bending beam rheometer (BBR) and direct tension test (DTT). The results of the investigation indicate that binder compounded with OPFA becomes less susceptible to temperature, improve resistance to rutting at 70 C, fatigue cracking at 20 C, and thermal cracking at -17 C of the surface pavement temperature compared to the unmodified bitumen. The OPFA-MB can be categorised as a binder with penetration grade of 60/70 or as PG 70-16 in the performance based system. Finally, it can be deduced that it is feasible to use OPFA as a modifier of bitumen.© 2013 Elsevier Ltd. All rights reserved. Source

Karlinasari R.,Islamic University of Sultan Agung | Rahardjo P.P.,Parahyangan Catholic University
Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils | Year: 2011

The uppermost zone of tropical residual soil is a zone of unsaturated soil with a unique characteristic. The uppermost zone intensively change from unsaturated-saturated phase, because the intensity of sun heat is high and the intensity of rainfall is much higher than it's soil permeability. A series of research on the unsaturated shear strength of tropical volcanic residual soil were conducted with Triaxial Consolidated Drained Unsaturated (TXCD-UNSAT ) Method. The research is resulted on unsaturated shear strength parameters. These parameters were evaluated with other research's results on unsaturated shear strength. An analysis based on the two methods of constitutive behaviour of unsaturated shear strength: The Two Independent Stress Variable Method and Effective Stress Method was conducted and the results confirm the published data. © 2011 Taylor & Francis Group, London. Source

Fachrunnisa O.,Islamic University of Sultan Agung
International Journal of Networking and Virtual Organisations | Year: 2014

The success of any interaction through a virtual medium can be determined by the continuity of service delivery. The promptness and competence of service, delivered as promised or agreed are indicators used to measure the success of service delivery. To ensure successful service delivery, we designed a proactive continuous performance monitoring and incentive mechanism. The delivery of service is checked at every intermediate point, so that the progress of the delivery can be monitored easily. With this monitoring design, performance discrepancies can be identified and resolved quickly, thereby preventing the escalation of a problem. Moreover, the incentive mechanism is designed to support continuous performance monitoring. It is proposed that the incentive be given at any intermediate checkpoint instead of at the end of the interaction. We built a prototype and conducted simulations under a variety of conditions. The experiment results show that our proposed framework is effective in facilitating successful service delivery. Copyright © 2014 Inderscience Enterprises Ltd. Source

Antonius,Islamic University of Sultan Agung
International Journal of Technology | Year: 2015

This paper presents the results of an experimental study of the behavior of high-strength steel fiber-concrete confined by hoops with round cross-sections subjected to concentric loadings. Behavior strength and energy absorption capability of confined fibrous concrete was the main focus of this study. Fibrous concrete test specimens were made by varying concrete's compressive strength and characteristics of hoops reinforcement (i.e., volumetric ratio and spacing). All specimens used longitudinal reinforcement with the same ratio. Experimental results showed that the strength enhancement of confined concrete reinforced with steel fiber is strongly influenced by the characteristics of the installed confining reinforcement. In this paper, the confinement models by researchers were evaluated and compared with the experimental results. The comparison between existing confinement models and experimental results were significantly different, especially in the post-peak behavior. Obtaining accurate characteristic predictions of high-grade confined fibrous concrete is necessary prior to modification of existing confinement models. © IJTech 2015. Source

Antonius,Islamic University of Sultan Agung
Asian Journal of Civil Engineering | Year: 2014

This paper presents on an experimental study of confined high-strength concrete columns tested under axial compression. The main objective of the research is to know the performance of spirals and hoops with medium strength (400 MPa < fy < 600 MPa) in their contribution on the behaviour of confined high-strength concrete columns. The parameters of the study were concrete strengths, confining steel characteristics i.e: type of confinement (spirals and hoops), yield strength, spacing and volumetric ratio. From the experimental results it was found that the strength enhancement and ductility of confined concrete will decrease with if both of concrete strength and spacing of spirals or hoops increase, and the strain in the test also showed that the release of a cover of concrete core occurs prematurely. Other results shows that satisfactory of circular hoops as confinement steel behaved as good as the spiral reinforcement. The spiral reinforcement provision adopted in the Indonesian Concrete Standard 2002 (SNI 03-2847-2002) is quite reliable when applied in the design of confining steel with medium strength of high-strength concrete columns, therefore it is proposed that the upper limit provision of yield strength of confining steel warrant to be modified. Source

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