Article Per Year (5 Year)
p-Index From 2021 - 2026
3.533
P-Index
This Author published in this journals
All Journal Jurnal Ilmiah Desain & Konstruksi Prosiding Seminar Nasional Sains Dan Teknologi Fakultas Teknik Jurnal Konstruksia E-Dimas: Jurnal Pengabdian kepada Masyarakat Syntax Literate: Jurnal Ilmiah Indonesia Civil Engineering Journal Jurnal Sinergitas PkM & CSR FaST : Jurnal Sains dan Teknologi Reka Buana : Jurnal Ilmiah Teknik Sipil dan Teknik Kimia JMTS: Jurnal Mitra Teknik Sipil Jurnal Pengabdian kepada Masyarakat Journal of Community Service and Engagement Prosiding Konferensi Nasional PKM-CSR Prosiding Seminar Nasional Teknik Sipil UMS Prosiding Seminar Nasional Teknik UISU (SEMNASTEK) Jurnal Jalan Jembatan Taawun: Jurnal Pengabdian kepada Masyarakat
Jack Widjajakusuma
Universitas Pelita Harapan
Religion Agriculture, Biological Sciences & Forestry Humanities Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Education Engineering Environmental Science Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Nursing Public Health Social Sciences Transportation Other

Published : 24 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 24 Documents
Search

 1   2   3 
PENINGKATAN KUAT TEKAN PADA BETON GEOPOLIMER AKIBAT METODE PERAWATAN DIPANASKAN Wibowo, Kevin Aprilio; Christianto, Daniel; Widjajakusuma, Jack
JMTS: Jurnal Mitra Teknik Sipil Volume 7, Nomor 1, Februari 2024
Publisher : Prodi Sarjana Teknik Sipil, FT, Universitas Tarumanagara

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24912/jmts.v7i1.25150

Abstract

Studies about pozzolan material to reduce cement usage have been conducted for many times. Concrete made of pozzolan material was known as geopolymer concrete. Geopolymer concrete’s weaknesses were low duration of setting time and the low level of workability. The precast method was used to overcome these weaknesses. Concrete with a high initial compressive strength enable a more efficient implementation of the precast method due to it able to be released from the formwork without getting damaged. This study aims to see the increase in compressive strength due to the method of dry curing. In addition to that, differing from the geopolymer concrete without palm oil fuel ash, this study added 5% of palm oil fuel ash to see the effect of it on compressive strength. Constructed specimens were then cured at room temperature or heated in an oven with a temperature of 60°C for 24 hours. The ratio of alkaline activator to fly ash that were used in this research are 0,55:1 and 0,825:1. The specimen which was only a day old with 0,55:1 ratio experienced 2 times increase in compressive strength when being heated compared to the specimen cured at room temperature. The specimen which was of the same age with 0,825:1 ratio also experienced 3,5 times increase in compressive strength after being heated compared to those at room temperature. The increase of compressive strength was due to the heating process enabling the chemical reaction to occur faster. Abstrak Penelitian untuk memanfaatkan material pozzolan untuk mengurangi penggunaan semen sudah banyak dilakukan. Beton yang menggunakan material pozzolan disebut beton geopolimer. Kelemahan dari beton geopolimer adalah durasi setting time dan tingkat kelecakan yang rendah. Oleh karena itu, metode pracetak dapat digunakan untuk mengatasi kelemahan tersebut. Beton dengan kuat tekan awal yang tinggi dapat membuat metode pracetak semakin efisien karena beton dapat dilepaskan dari bekisting dan tidak rusak. Penelitian ini bertujuan untuk melihat peningkatan kuat tekan akibat metode perawatan benda uji dengan cara dipanaskan. Selain itu, pada penelitian ini ditambahkan abu cangkang kelapa sawit sebanyak 5% untuk dilihat pengaruhnya terhadap kuat tekan dibanding beton geopolimer tanpa abu cangkang kelapa sawit. Benda uji yang sudah dibuat, dirawat pada suhu ruangan atau dipanaskan pada oven dengan suhu 60°C selama 24 jam. Rasio alkali aktivator terhadap abu terbang yang digunakan pada penelitian ini adalah 0,55:1 dan 0,825:1. Hasil peningkatan kuat tekan yang didapat pada saat benda uji berumur 1 hari adalah benda uji dengan rasio 0,55:1 yang dipanaskan mengalami peningkatan kuat tekan sekitar 2 kali dan pada rasio 0,825:1 mengalami peningkatan kuat tekan sekitar 3,5 kali dibanding benda uji yang dirawat pada suhu ruangan. Hal itu disebabkan oleh pemanasan benda uji membuat reaksi kimia terjadi lebih cepat dan kuat tekan meningkat.
The Role of Geopolymer Concrete in Achieving Sustainable Development Goals Wibowo, Kevin Aprilio; Widjajakusuma, Jack
FaST - Jurnal Sains dan Teknologi (Journal of Science and Technology) Vol. 9 No. 1 (2025): NOVEMBER
Publisher : Universitas Pelita Harapan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19166/jstfast.v9i2.10386

Abstract

A sense of safety and comfort is a fundamental right for all people. The United Nations strives to fulfil this through the establishment of 17 Sustainable Development Goals (SDGs). The construction sector plays a significant role in achieving these goals, particularly in the areas of Good Health and Well-being, Clean Water and Sanitation, Decent Work and Economic Growth, Sustainable Cities and Communities, Responsible Consumption and Production, and Climate Action. One key effort in the construction sector is replacing Portland cement with pozzolanic materials. Cement production emits large amounts of carbon dioxide, contributing substantially to global warming. To address this, pozzolanic materials such as fly ash are used as a substitute for cement in the production of geopolymer concrete. Based on compressive strength tests on cylindrical specimens and flexural strength tests on beam specimens, geopolymer concrete demonstrates high potential for structural applications. Its mechanical performance is comparable to that of conventional concrete, making it a promising alternative that supports sustainable development in the construction industry.
High-Reliability Teams at Sea: The Role of Psychological Safety, Human–System Interaction, and Workload in Error Reporting Behavior among Offshore Workers Gomargana, Chrysan; Wibowo, Kevin Aprilio; Widjajakusuma, Jack
FaST - Jurnal Sains dan Teknologi (Journal of Science and Technology) Vol. 9 No. 1 (2025): NOVEMBER
Publisher : Universitas Pelita Harapan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19166/jstfast.v9i2.10416

Abstract

Offshore oil and gas operations demand high reliability under extreme physical and psychological conditions. Despite robust engineering systems, many accidents still stem from human and organizational factors. This study examines the role of psychological safety, human–system interaction, and workload in predicting error reporting behavior among offshore workers. A quantitative, cross-sectional design was applied using validated self-report scales: the Psychological Safety Scale (Edmondson), System Usability Scale (SUS), NASA Task Load Index (NASA-TLX), and an adapted Error Reporting Behavior Scale. Data were collected from 188 offshore workers in Indonesia through online questionnaires. Multiple linear regression analysis revealed that psychological safety (β = .38, p < .001) and human–system interaction (β = .27, p < .001) significantly and positively predicted error reporting behavior, while workload showed a significant negative effect (β = −.23, p < .001). The model accounted for 36% of the variance in error reporting (R² = .36). These findings indicate that workers are more likely to report errors when they feel safe to speak up, perceive systems as user-friendly, and experience manageable workloads. The study highlights the need for integrated interventions that simultaneously foster psychological safety, ergonomic system design, and balanced workload management to enhance proactive safety behavior in offshore environments. This research contributes to the intersection of industrial–organizational psychology and human factors engineering, emphasizing that safety performance in high-reliability organizations relies on both social and technological resilience. These findings align with Sustainable Development Goal 9 (Industry, Innovation and Infrastructure), reinforcing that resilient and sustainable industrial systems require the integration of human factors into safety management and system design.
Performance of Soil Biogrouting as a Subgrade Material of the Road Pavement Widjajakusuma, Jack; Waruwu, Aaazokhi; Kusnadi, Yulia Yunita; Lujaya, Jason; Wibowo, Kevin Aprilio
Civil Engineering Journal Vol. 11 No. 10 (2025): October
Publisher : Salehan Institute of Higher Education

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.28991/CEJ-2025-011-10-017

Abstract

Soft clay subgrade is unsuitable for road pavement because it has low bearing capacity and CBR value. Therefore, the soil needs stabilization, but with a sustainable stabilization method. One of these methods is biogrouting, namely grouting, which uses bacteria. Thus, the main objective of this study was to determine the performance of Bacillus subtilis and Bacillus amyloliquefaciens bacteria in stabilizing the soil. The performance of these bacteria was quantified by the CBR value and soil-bearing capacity experimentally in a laboratory model test with each soil thickness of 0-30 cm. The CBR value of the soil improved by the biogrouting method by about 4 times the CBR value of untreated soil. The increase in bearing capacity was obtained about 4 times for treated soil with Bacillus subtilis and about 5 times for treated soil with Bacillus amyloliquefaciens. The layer thickness significantly improves the performance of the subgrade at a layer thickness of 20 cm. The new result of this study is that both bacteria are native Indonesian bacteria, so they are suitable for use in Indonesia. In addition, Bacillus amyloliquefaciens has never been used in research to increase soil-bearing capacity.
Co-Authors A Hasyati A.G. Hendra Aazokhi Waruwu Aji Sulistian Akbar Lubis Akhmad Suraji, Akhmad Buntoro, Flory Daniel Christianto Daniel, Christian Gerald Dr. Adolf J.N. Parhusip Edricnes Gomargana, Chrysan Heri Khoeri Heri Khoeri I.T. Wiguna I.T. Wiguna Indriantari Sekarrini Indriantari Sekarrini Janice A.P. Pramono Janice A.P. Pramono Kevin Aprilio Wibowo Krishna A. Perdana Kusnadi, Yulia Yunita Kusumah, Intan Permata Lia Apriliani Lujaya, Jason M. U. Al-abqori M.A.Kholik M.A.Kholik M.I. Alfajri M.I. Alfajri Manlian Ronald A. Najid Najid Nasya I. Arifa Natasa, Fani Nisvi S. Dewi8, S.F Nisvi S. Dewi8, S.F Nisvi Suciati Dewi Polii, Brian Denzel Pramono, Rudy Pubby Vianohita Pubby Vianohita Purba, Sadvent Martondang Rahayu, Priskila Christine Reinhard Pinontoan Rika Deni Susanti Riska Apriliani S.F. Jamaludin S.F. Jamaludin S.F. Jamaludin S.F. Jamaludin Saputan, Clairine Silalahi, Andreas Partogi Siti A. Napilah Siti A. Napilah Siti H.T Jammalliah Siti H.T. Jammalliah Siti H.T. Jammalliah Siti N. Napilah Sofia Wangsadinata Alisjahbana Sofiana, Dini Sondakh, Joshua Sumantri, Nicholas Anthony Tanuhendrata, Michael Wachid Tristanto Waruwu, Aaazokhi Waruwu, Aazokhi Wibowo, Kevin Aprilio Widjaya, Valencio Stephen Wisnu Isvara, Wisnu Yundari, Yundari