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121	Materials Science	ABS-268
Microstructure Analysis and Hardness Test of Branch With Reinforced Pad After Close Range Multilayer Welding Spool 4I84-0008-01-1 Line Projects Dianita Wardani, Budi Prasojo, Widya Emilia, George Endri Politeknik Perkapalan Negeri Surabaya Abstract Project Line spool fabrication is a pipe manufacturing project for factories chemistry in Cilegon where there are many spool fabrication problems, especially in spool with number 4I84-N-0008-01-1. This welding experienced problems in the form of microstructural defects that impact the hardness of the material in that area Reinforced bearings. This defect causes the material to not meet standards The maximum hardness is determined by the project owner^s specifications, so that repairs must be carried out with Post Weld Heat Treatment (PWHT). Study It uses the Vickers Hardness testing method to evaluate material hardness, with a maximum acceptable hardness criterion of 250 HV. Apart from that, metallographic testing was also carried out to understand the changes microstructure due to the adjacent multilayer welding process. Testing Metallography was performed according to ASTM E3 standards, with the aim of finding influence of heat treatment on welding. The research steps include initial identification, data collection, test preparation, metallographic testing and Vickers hardness, as well as data processing. Primary data was obtained through interviews with the Workshop Team and Quality Checking team, while data secondary includes Material Data and NCR spool. The test results show that the hardness of the material after close-range multilayer welding is still deep acceptable hardness range, despite changes in microstructure significant in the HAZ (Heat Affected Zone) region. The end of this research is that multilayer close welding has the potential to affect the microstructure and material hardness. However, the material still meets standards determined without the need for additional Post Weld Heat Treatment (PWHT). Keywords: Mettalography, Piping Spool, Piping Welding, Hardness Keywords: Mettalography, Piping Spool, Piping Welding, Hardness Share Link | Plain Format | Corresponding Author (Dianita Wardani)

122	Materials Science	ABS-269
Testing the Compressive Strength of Concrete: Comparing Direct Test Results with Conversion Values Firmanilah Kamil, Julyan Purnomo Politeknik Negeri Ketapang Abstract This study discusses testing the compressive strength of concrete at 7 days, 14 days, and 28 days, and evaluates the accuracy of the conversion values used to estimate the compressive strength of concrete at older ages. The compressive strength of concrete is an important parameter in assessing the quality and resistance of materials to structural loads. Direct testing at various ages gives an idea of the development of concrete strength, but in many cases, conversion values are used to save time and cost. This study conducted experimental tests in the laboratory, where concrete samples were tested at 7, 14, and 28 days of age. These test results were then compared with conversion values calculated using empirical formulas commonly used in the concrete industry. The results showed that there were significant differences between the direct test results and the conversion values, especially for concrete with additives such as fly ash and rice husk. The conversion values from 7 days to 28 days are often inaccurate, while the conversion from 14 days to 28 days is closer to the direct test results. Factors such as the type and proportion of additives, curing conditions, and the mismatch of the conversion model with the strength development of the concrete also influenced the final results. These findings emphasize the need for caution in using conversion values to assess the compressive strength of concrete to ensure the quality and safety of structures. Keywords: Age of concrete, Concrete compressive strength, Concrete testing, Conversion value, Curing concrete Share Link | Plain Format | Corresponding Author (Firmanilah Kamil)

123	Materials Science	ABS-38
Analysis of the Tensile Strength of Composite Material: Plywood Composite Matrix Based on Epoxy Resin for the Construction of Flat River Shallow Water Vessels Budhi Santoso, M Helmi, Edy Haryanto, Romadhoni Politeknik Negeri Bengkalis Abstract This study investigates the mechanical properties of composite materials under tensile stress at different lamination angles, specifically 0 degrees and 90 degrees. The tensile tests measured parameters such as tensile stress and modulus of elasticity for various samples. The results indicate significant variations in mechanical properties based on the orientation of the fibers within the composite material. At 0 degrees, where fibers are aligned with the direction of the tensile force, some samples exhibited higher tensile stress and modulus of elasticity, with values reaching up to 1679.92 and 63.815, respectively. Conversely, at 90 degrees, where fibers are perpendicular to the tensile force, certain samples showed increased modulus of elasticity, with values as high as 2066.987. However, other samples demonstrated a decrease in mechanical properties at this orientation. These findings highlight the critical role of fiber orientation in determining the mechanical performance of composite materials, emphasizing the need for careful consideration of lamination angles in material design and engineering applications. The study underscores the importance of selecting appropriate fiber orientations to optimize the strength and stiffness of composite materials for specific applications, ensuring their reliability and efficiency in various engineering contexts. Keywords: Elastic Modulus, Tensile Stress, Lamination Angle, Composite Material, Mechanical Properties, Tensile Testing Share Link | Plain Format | Corresponding Author (Budhi Santoso)

124	Materials Science	ABS-40
INITIAL STRAIN of PLAIN BAR IN LIGHTWEIGHT BRICK as PRECAST CONCRETE SLAB Pratikto, Anni Susilowati Department of Civil Engineering, State Politeknik Negeri Jakarta Abstract The public has a strong desire for multi-story houses, which developers are choosing to build. When compared to extensions done horizontally, the expenditure for structures expanded vertically can be smaller. The industry uses the execution of floor plate work that is lightweight and can be completed quickly. A reasonably priced and robust concrete floor slab route can be formed by stacking lightweight bricks in a precast manner. With a compressive strength of 5 MPa, lightweight concrete bricks are made of cement, fine aggregate, and foaming agents. The light bricks are 20 by 10 by 60 mm, and they are put together with plain bar P10 reinforcement at each corner and covered in concrete mortar to create a one-way slab concrete. The reinforcement is positioned in the best possible locations and covered with concrete in accordance with the 20-mm code. A hole is drilled in the middle of the cross-section to accommodate the P10 reinforcement, which is going to bear the brunt of the initial strain. A multi-story house^s floor slab is made up of multiple one-way slab strips joined together as precast concrete slabs. The strength test of this line is reviewed based on the deflection adjusted to the SNI 2847-2019 permit deflection for concrete, namely not exceeding L/360, so that for a span of 90 cm, it is found to be 25 mm. The load acting on the floor slab apart from the load itself is the live load of the residential house according to SNI 1727-2020, at least 1.92 kN/m2 or 200 kg/m2. The results of several loading tests with a pure bending moment on a span of 90 cm from two types of beams with and without initial strains were found to be 500 kgf and 270 kgf, respectively. The load resulting from a system with an initial strain can increase the load by 146%. The presence of initial strains in the cross-section can increase the ability of a series of lightweight bricks to serve as precast concrete slabs. Keywords: initial strain, lightweight brick , pure bending moment Share Link | Plain Format | Corresponding Author ( )

125	Materials Science	ABS-41
INITIAL STRAIN of PLAIN BAR IN LIGHTWEIGHT BRICK as PRECAST CONCRETE SLAB Pratikto, Anni Susilowati Department of Civil Engineering, State Politeknik Negeri Jakarta, Abstract The public has a strong desire for multi-story houses, which developers are choosing to build. When compared to extensions done horizontally, the expenditure for structures expanded vertically can be smaller. The industry uses the execution of floor plate work that is lightweight and can be completed quickly. A reasonably priced and robust concrete floor slab route can be formed by stacking lightweight bricks in a precast manner. With a compressive strength of 5 MPa, lightweight concrete bricks are made of cement, fine aggregate, and foaming agents. The light bricks are 20 by 10 by 60 mm, and they are put together with plain bar P10 reinforcement at each corner and covered in concrete mortar to create a one-way slab concrete. The reinforcement is positioned in the best possible locations and covered with concrete in accordance with the 20-mm code. A hole is drilled in the middle of the cross-section to accommodate the P10 reinforcement, which is going to bear the brunt of the initial strain. A multi-story house^s floor slab is made up of multiple one-way slab strips joined together as precast concrete slabs. The strength test of this line is reviewed based on the deflection adjusted to the SNI 2847-2019 permit deflection for concrete, namely not exceeding L/360, so that for a span of 90 cm, it is found to be 25 mm. The load acting on the floor slab apart from the load itself is the live load of the residential house according to SNI 1727-2020, at least 1.92 kN/m2 or 200 kg/m2. The results of several loading tests with a pure bending moment on a span of 90 cm from two types of beams with and without initial strains were found to be 500 kgf and 270 kgf, respectively. The load resulting from a system with an initial strain can increase the load by 146%. The presence of initial strains in the cross-section can increase the ability of a series of lightweight bricks to serve as precast concrete slabs. Keywords: initial strain, lightweight brick , pure bending moment Share Link | Plain Format | Corresponding Author (Pratikto tito)

126	Materials Science	ABS-46
The Durability of Laston AC-WC Warm Asphalt Concrete with Rediset Added MaterialsPlease Just Try to Submit This Sample Abstract Anni Susilowati, Eko Wiyono and Pratikto Politeknik Negeri Jakarta Abstract Warm Mix Asphalt (WMA) is a type of asphalt mixture that uses technology based on green technology. It is produced with a mixing and compaction temperature lower (200C to 400C) than the mixing temperature for hot mix asphalt (Hot Mix Asphalt, HMA). To improve the bond between aggregate and asphalt, Rediset LQ1106 was added. The durability of asphalt concrete mixtures influences a road^s performance and service life. The study aimed to obtain the property value of Marshall asphalt concrete mixture with the variation of immersion time at a fixed temperature of 600C and the durability of warm asphalt concrete mixture AC-WC. Marshall immersion modification was carried out in the time of 6, 12, 18, 24, 30, 36, 42, 48 hours with an optimum asphalt content of 6.25% and Rediset LQ1106 2.25% against the Optimum Asphalt Content-Marshall test method based on SNI 06-2489-1991. The parameters used to see the durability level of the results of the study showed that the Marshall characteristic values which included VMA, VFB, VIM, Stability, Flow and MQ were 18%- 75.7%- 4.4%- 1116kg- 3.5 mm, and 318.9kg/mm, respectively. The longer the asphalt mixture is submerged in water, the more the durability of the AC-WC warm asphalt concrete mixture decreases, both in terms of the Residual Strength Index (IKS) and the Durability Index value. The IKS value required by Bina Marga, (2018) is 90%. The Durability Index of test specimens that have decreased in strength is quite large along with the increase in immersion time compared to normal test pieces, so that test specimens that have undergone aging are considered not sufficiently resistant to damage caused by the influence of water Keywords: Asphalt mixture, Stability, Durability, Immersion marshall Share Link | Plain Format | Corresponding Author (Anni Susilowati)

127	Materials Science	ABS-72
Self-Healing Concrete Using Alginate Encapsulation of Bacillus Megaterium Bacteria Muhammad Hafizh (a), Luthfi Muhammad Mauludin (a*), Ambar Susanto (a), Keryanti (b), Gandhi Widiarnoko (c) a) Civil Engineering Department, Politeknik Negeri Bandung, Jl. Gegerkalong Hilir, Bandung Barat, Indonesia *luthfi-mm[at]polban.ac.id b) Chemical Engineering Department, Politeknik Negeri Bandung, Jl. Gegerkalong Hilir, Bandung Barat, Indonesia c) PT. Bintang Solusi Bersama, Jakarta Selatan, Indonesia Abstract Self-healing concrete is a concrete technology that is mixed using microorganisms in the form of bacteria so that the concrete can repair itself when cracks occur. Making self-healing concrete is a preventive measure to repair small cracks so they don^t become bigger. This also functions as an action to reduce the use of epoxy injection materials which are toxic to the environment and human life. The research method used in this research is a trial/experimental method using Bacillus Megaterium bacteria as a healing agent and microcapsule material made from alginate as a coating for the bacteria (encapsulation). The test object made is in the form of a block with dimensions of 500 x 100 x 100 mm. The percentage of added microcapsules used was 1%, 2%, and 3%. Flexural strength tests were carried out when the concrete was 7 and 28 days. Mechanical testing on microcapsules is also carried out to see the strength of the microcapsule material that will be used. The results obtained from this research were that the highest flexural strength occurred with the addition of a variation of 2% alginate microcapsules, namely 13.5 MPa on day 7 and 16 MPa on day 28. The tensile strength of alginate microcapsules was 0.02365 MPa with plate specimens measuring 65 x 27.45 x 5 mm. From the results of visual observations, healing process in the concrete began to occur on the 7th day after the bending test. After 28 days of curing, the specimens were tested again for the second time to determine the return to strength of the concrete that had been tested for flexural strength. From the test results, the greatest return to strength was obtained when 3% microcapsules were added to the concrete. The strength gain was 102%. The optimum percentage level of microcapsules to be added to concrete is 2% because it has a sufficiently increased flexural strength value and has a recovery ability of 92%. Keywords: Encapsulation, Bacillus megaterium, Alginat, Flexural Strength, Self-healing concrete Share Link | Plain Format | Corresponding Author (Muhammad Hafizh)

128	Materials Science	ABS-75
Compressive Strength of Steel Fiber Reinforced Concrete Indah Permatasary (a*), Mardiana Oesman (a), Suharwanto (b), Ambar Susanto (a) a) Department of Civil Engineering, Faculty of Engineering, Polytechnic State of Bandung Jl. Gegerkalong Hilir, Bandung Barat 40559, Indonesia *mardianaoesman[at]polban.ac.id b) Department of Civil Engineering, Faculty of Engineering, University of Wiralodra Jl. Ir. H Juanda KM. 03, Indramayu 45213, Indonesia Abstract Steel Fiber Concrete (SFC) consists of hydraulic cement material, coarse aggregate, fine aggregate, and steel fibers dispersed within the concrete mix. Steel fibers serve as an alternative additional material to address the issue of cracking that commonly occurs in reinforced concrete. The performance capability of steel fibers is combined with the concept of Self-Compacting Concrete (SCC), which is then referred to as Self-Compacting Steel Fiber Concrete (SC-SFC). A study was conducted on the compressive strength of concrete, with cylindrical test specimens measuring 100 x 200 mm, with three samples each tested at 7 days and 28 days of age. The SFC mix design was based on previous research with a water/binder ratio (w/b) of 0.45 and the addition of 2% steel fiber by volume fraction. The steel fibers used were produced by PT. Bakaert, with a length of 30 mm and hooked ends, type 80/30BGP. The results showed that the average compressive strength of SFC increased by 31.7% from 7 days to 28 days, with a compressive strength value (f^c) of 20.1 MPa. Keywords: Steel Fiber Concrete (SFC)- Self-Compacting Concrete (SCC)- Compressive strength Share Link | Plain Format | Corresponding Author (Indah Permatasary)

129	Materials Science	ABS-76
The Effectiveness of Microorganisms EM4 as a Self-Healing Injection Material for Concrete Crack Repair Luthfi Muhammad Mauludin(a*), Ery Radya Juarti(a), Ridho Septian(a), Linda Aisyah(a) and Baso Muhammad Ilham Alimin(a) a)Civil Engineering Department, Politeknik Negeri Bandung, Jl. Gegerkalong Hilir, Ciwaruga, Bandung, Indonesia *luthfi-mm[at]polban.ac.id Abstract Cracks in concrete structures typically arise from natural processes, excessive loads, or mistakes in design and construction. This study evaluates the effectiveness of the probiotic microorganism EM4 as a self-healing injection material for repairing concrete cracks. EM4, known for improving soil structure and organic materials, is expected to fill gaps in concrete. The study uses EM4 in proportions of 5%, 10%, 15%, 20%, and 25% of the total injection weight to assess its ability to repair cracks in test beams measuring 50x100x100 mm, subjected to flexural strength testsThe effectiveness of EM4 is compared with epoxy injection and bacillus megaterium bacteria, both of which have been shown to be effective in concrete repair. EM4 at a 15% concentration increases flexural strength by 6.45%, though this improvement is less than Bacillus megaterium, which achieved a 12.19% increase. However, the results show that EM4 is more effective than conventional epoxy injection materials. These findings are expected to reduce the need for additional materials and energy, decrease repair waste, extend the lifespan of concrete, and contribute to the development of efficient, environmentally friendly, sustainable construction technologies. Keywords: Self-Healing Concrete, EM4 Probiotic Microorganisms, Concrete Crack Repair, Sustainable Construction, Flexural Strength Testing Share Link | Plain Format | Corresponding Author (Baso Muhammad Ilham Alimin)

130	Materials Science	ABS-82
Characterization of Water Hyacinth Extract by Vacuum Microwave Assisted Extraction (VMAE) Method for Corrosion Inhibitor on ASTM A36 Plate in 1 M H2SO4 Environment Tifa Paramitha (a), Unung Leoanggraini (a), Dava Maulana Malik (a), Angely Luviana (a), Angelina Putri (a), Santy Nurhasanah (a), Shafira Salsabila (a), dan Rony Pasonang Sihombing(a*) a) Chemical Engineering, Politeknik Negeri Bandung, Jl. Gegerkalong Hilir, Bandung Barat 40559, Indonesia *rony.pasonang.sihombing[at]polban.ac.id Abstract Water hyacinth is a plant that is very abundant in Indonesia. One of the utilizations of water hyacinth is for corrosion inhibitors. The type of media applied in this research is an acidic media, which is H2SO4 solution. The purpose of this research is to investigate the application of water hyacinth extract for inhibitor corrosion. The extract was obtained by VMAE method at 300 watts power for 8-, 10-, and 15-minutes using ethanol solvent. The ratio of feed and solvent used was 1:15 (b/v). Then, extract was analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and tested to phytochemical tests using Dragendroff, Wagner and Mayer reagents. After that, the extract was applied as inhibitor corrosion on ASTM A36 Plate. Based on the results of extract analysis, terpenoid and phenol compounds was detected on water hyacinth extract, in which these two compounds are antioxidant substances that can be utilized as corrosion inhibitors. The results of the corrosion study showed that the lowest corrosion rate was obtained at a concentration of 2000 ppm, namely 9,396 mmpy. Metal samples were subjected to qualitative tests using SEM-EDX and XRD. From these tests, the amount of Fe content decrease and the formation of crystalline phases such as Fe24N10 were obtained. Keywords: Water Hyacinth, VMAE, corrosion inhibitor Share Link | Plain Format | Corresponding Author (Rony Pasonang Sihombing)

131	Materials Science	ABS-83
HDPE Floating Jetty Design as A Supporting Facility for River Transport Kharis Abdullah (a*) a) Shipbuilding Engineering Department, Politeknik Perkapalan Negeri Surabaya Abstract Floating Jetty or commonly known as a floating dock, is one of the facilities at the port to take passengers from ship to land or vice versa. River transport is one of the transport routes that is quite widely used by the Indonesian people. HDPE (High Density Polyethylene) material can be used for the construction of marine buildings and buildings in freshwater waters. The use of HDPE material as an alternative material to become a floating dock is an alternative to the use of environmentally friendly and recyclable materials. In this research, a floating dock will be planned using HDPE material to support river transport. Keywords: HDPE- Ship- Design- Construction Share Link | Plain Format | Corresponding Author (Kharis Abdullah)

132	Materials Science	ABS-126
Analysis of the Effect of Shop Primer on the Adhesion of Fuel Oil Tank Paint on Hospital Auxiliary Ships Imah Luluk Kusminah1,b), Dika Rahayu Widiana2,a), Am Maisarah Disrinama3,b), Endang Fitria Rahmawati4,b), Laili Fitria5,b), and Ersa Mei Dwiningsih6 1Department of Welding Fabrication and Engineering, Politeknik Perkapalan Negeri Surabaya, Surabaya, 60111, Indonesia 2Magister of Safety and Risk Engineering, Politeknik Perkapalan Negeri Surabaya, Surabaya, 60111, Indonesia 3Department of Occupational Safety and Health Engineering, Politeknik Perkapalan Negeri Surabaya, Surabaya, 60111, Indonesia 4 Department of Environmental Engineering, Chung Yuan Christian University, Taoyuan 32023, Taiwan 5 Department of Environmental Engineering, Tanjungpura University, Pontianak 78124, Indonesia 6Department of Design and Construction Engineering, Politeknik Perkapalan Negeri Surabaya, Surabaya, 60111, Abstract Steel is widely used as a raw material for shipbuilding in the marine industry. One is the Hospital Auxiliary Ship, which uses steel as its fuel tank material. Steel is susceptible to corrosion, so the material requires coatings to protect it from the effects of corrosion. This study covered the materials with primary deposits before fabrication to provide temporary protection during material storage and construction. After constructing the fuel tank, the entire surface of the material is covered with anticorrosion paint. The shop coat of primer was removed following SSPC SP10/NACE2/SA2.5 surface cleanliness standards. Next, the paint adhesion test was carried out by varying the remaining primer to 0%, 50% and 100%. The paint shop primer used is anticorrosion paint Jotun Muki Z and Jotun Tankguard HB Classic. The paint adhesion test uses the pull-off adhesion test method according to ASTM D-4541. The results of the paint adhesion test on materials without primer residue were 14.3 MPa, materials with 50% primer residue were 7.25 MPa, and materials with complete shop primer were 6.06 MPa. The material that has the best adhesion is material without a primary shop. Keywords: Coating, Corrosion, Jotun Paint, Pull Off Test, Shop Primer Share Link | Plain Format | Corresponding Author (Dika Rahayu Widiana)

133	Materials Science	ABS-129
The Effect of Submerged Arc Welding Slag on the California Bearing Ratio Value of Subbase Course Yelvi, Muhammad Noval Harlande, Rikki Sofyan Rizal, and Eva Azhra Latifa Politeknik Negeri Jakarta Abstract The foundation layer is the part of the road pavement located beneath the surface layer that receives most of the load distribution from vehicles to the subgrade. With the advancement of time, especially in the construction industry, many innovations have been made to obtain foundation materials that meet specifications and are more affordable, one of which is the utilization of waste. This study utilizes waste from SAW (Submerged Arc Welding) as a substitute in the subbase course. The aim of this research is to determine the effect of SAW waste substitution on the CBR (California Bearing Ratio) value of the subbase course. The variations of SAW waste used as a substitution material in the subbase course are 0%, 10%, 15%, and 20%. The CBR soaking test refers to SNI 1744:2012 and the requirements are based on the Spesifikasi Umum Bina Marga Revisi II 2018. The CBR test results showed a decrease in SAW waste variations of 0%, 10%, 15%, and 20%, which were 97.2%, 69.1%, 67.5%, and 64.3%, respectively. However, the lowest result, which is the 20% SAW waste variation, still meets the requirements, which is &#8805- 60% for the subbase course. Keywords: CBR, SAW, Subbase Share Link | Plain Format | Corresponding Author (Yelvi Yelvi)

134	Materials Science	ABS-131
Effects of Welding Current on the Mechanical Properties of Gas Tungsten Arc Welding Welded ST 37 Plates using Cannibal Consumable Filler Albert Daniel Saragih, Riswanda, Prasetyo, Syahrul Dwi Nugraha and TB. Moch mario Al-Qashtalani Politeknik Negeri Bandung Abstract In this paper, the macrostructure and mechanical properties of low carbon steel with itself filler by using the GTAW process have been investigated. The low carbon steel (ST 37) plates with dimensions of 300 x 250 x 3 mm was used for welding and 2.5 mm of thickness for the filler. For welding parameters, three distinct current of 80, 90, and 100 were observed over the welded specimens. To explore the optimum welding current, both tensile and bending tests were carried out. Both the visual and the macrograph showed that the weld seam produced on both the face and root is more stable, compared to using other currents. Destructive tests have suggested that welding current was 90 A is better for the GTAW process with itself material as a filler Keywords: Mechanical, Filler, GTAW, Current, Share Link | Plain Format | Corresponding Author (Albert Daniel Saragih)

135	Materials Science	ABS-169
The Behavior of Reinforced Concrete Columns under Axial Compressive Load Fahmi Dewa Kesuma (a), Mardiana Oesman (a*), Suharwanto (b) and Luthfi Muhammad Mauludin (a) a) Department of Civil Engineering, Faculty of Civil Engineering, Bandung States of Polytechnic, 40559 West Bandung, Indonesia *mardianaoesman[at]polban.ac.id b) Department of Civil Engineering, Faculty of Engineering, University of Wiralodya Abstract This study aims to determine the behavior of Reinforced Concrete Column Structural Elements under Axial Compressive Load. The structural elements used were four reinforced concrete columns with normal concrete plan quality f^c 20 MPa, with dimensions 200 mm x 200 mm x 750 mm reinforcement ratio 1.3% with longitudinal reinforcement 4D13 and stirrups D10-50 support and D10-100 field. During the experimental testing, the acting load and deformation were observed. The test results were then processed into the load-to-deformation relationship curve data and observations of collapse mechanisms, crack patterns, and possible delamination. The results showed that there was a difference in the deformation behavior that occurred in the CP2 column which was not homogeneous so that the column could not maximally accept the axial load. Specimens with the highest stiffness values were CP-2, CP-1, CP-3, and CP-4 with 244,010 kN, 213,623 kN, 195,530 kN, and 190,272 kN, respectively. The specimens with the highest ductility ability are CP-1, CP-3, CP-4, and CP-2 with values of 10.00, 6.717, 6.527, and 5.184, in order Keywords: Columns- Axial compressive load- Stiffness- Ductility Share Link | Plain Format | Corresponding Author (Fahmi Dewa Kesuma)

136	Materials Science	ABS-180
Marshall Immersion Performance of Asphalt Concrete - Binder Course Mixture by Utilizing Silica Waste as Fine Aggregate Substitution Lusyana,Mukhlis,Enita Suardi,Latifa Khairunnisa,Muhammad Huzzairi Politeknik Negeri Padang Abstract Damage or failure often occurs in Asphalt Concrete - Binder Course (AC-BC) pavement layers. This is characterized by damage that appears in the form of grain stripping and surface defects in the form of holes to fatigue cracks. The number of road failures indicates that silica sand needs to be used as a substitute for fine aggregate to improve the quality of the pavement. Silica sand substitution is expected to increase pavement durability. Based on the IRS, IDF, and IDS values obtained for each mix, the mix substituted without silica (0%) showed the smallest average loss of soaking strength compared to the other mixes. However, although the IRS decreased, silica sand can still be used because the IRS value still meets the specification of at least 90%. Keywords: AC-BC, Silica Sand, KAO Marshall, Marshall Immersion, Asphalt Film Thickness. Share Link | Plain Format | Corresponding Author (Lusyana Lusyana)

137	Materials Science	ABS-197
Improvement of Flexural Performance of Post-Fire Reinforced Concrete Beams Using Anchored Steel Plate Deliar noor (a), Riawan Gunadi (a*) a) Department of Civil Engineering, Applied Science Master of Infrastructure Engineering, Politeknik Negeri Bandung, 40559 Bandung Barat, Indonesia Abstract The degradation of structural performance due to fire is a critical issue, as it can significantly reduce a structure load bearing capacity after exposure to high temperatures. This study investigates the flexural performance of reinforced concrete beams subjected to fire and subsequently repaired using a 5 mm thick ST 370 steel plate. Three beam specimens, each with dimensions of 15 x 20 x 200 cm and a concrete strength of 25 MPa, were fabricated. These beams were exposed to a temperature of 750 C for 5 hours, resulting in spalling and a noticeable change in the concrete appearance and cross section. The performance of the post fire beam without repair (B01) decreased by 17.4% compared to the control specimen, while the repaired beam (SP5mm) showed a 3% improvement in maximum load capacity. The ductility values for the control specimen, specimen post fire (B01), and specimen repairing with steel plate (SP5mm) were 4.7, 2.4, and 2.3, respectively. The findings suggest that while the steel plate repair method can improve the load capacity of fire-damaged beams, it does not fully restore their ductility Keywords: Reinforcement Concrete Beam, Post Fire, Anchored Steel Plate Share Link | Plain Format | Corresponding Author (Deliar Noor)

138	Materials Science	ABS-208
Behavior of Concrete Beam Strengthened with UHPC Syifa Nadia Iskandar (a), Mardiana Oesman (a*) (a) Department of Civil Engineering, Applied Master of Infrastructure Engineering, Polytechnic State of Bandung JL. Gegerkalong Hilir, Bandung Barat 40559, Indonesia *mardianaoesman[at]polban.ac.id Abstract According to the Minister of PUPR, at least 40% of bridges in Indonesia are in poor condition. Ultra High Performance Concrete (UHPC) is one alternative material that can be used as reinforcement for concrete structural elements. The behavior of a concrete beam strengthened with UHPC layer in the tensile area was investigated experimentally. Next, the behavior of a concrete beam strengthened with UHPC will be compared with a concrete beam strengthened with normal concrete with the same thickness of 50 mm. The behavior of concrete beams is analyzed for stiffness, toughness, ductility and cracking mode. The results of the study indicate that the concrete beam strengthened with UHPC can increase the maximum load, ultimate load, yield load, and greater deflection so that they have greater ductility. Strengthened concrete beam with UHPC can increase the toughness by 32.9%, the stiffness by 13.5%, the ductility by 85%. In the B-UHPC 50 composite beam, the cracking mode was caused by flexural cracking- whereas, in the B-NC 50 composite beam the cracking mode was caused by flexural shear cracking. Keywords: UHPC, compressive strength, local materials, retrofit, beam Share Link | Plain Format | Corresponding Author (Syifa Iskandar)

139	Materials Science	ABS-211
The Reinforced Concrete for Production of Teaching Factory Febriane Paulina Makalew, Seska Nicolaas, Rilya Rumbayan, Vicky Alexander Assa Manado State Polytechnic Abstract Building construction has varied types of structural elements and materials used. Reinforced concrete is one of the most common uses in designing and constructing buildings. The need for facilities on the other hand has created a large market demand for effective and efficient processes of providing building and its infrastructure. A sustainable building process could be achieved by preparing a construction plan by providing materials in advance before on-site work starts. Therefore, this research aims to describe the production of the product of concrete reinforced rafting for the structure of foundation, beam, slab, and column effectively and economically. The method used is a literature study and laboratory test. The result shows the product can be produced by managing the process of production, the material available, and the workers of students, lecturers, and technicians. Further research needs to be conducted for complex types of reinforced and market approaches. Keywords: Reinforced concrete, Building, Structure, Teaching Factory, Rafting Share Link | Plain Format | Corresponding Author (Febriane Paulina Makalew)

140	Materials Science	ABS-220
Estimation of Warping Rate Under Extrusion Layer 3D Printing Based on Fused Deposition Modeling (FDM) Cholid Mawardi, Dwi Riyono, Joko Setiaji, Antinah Latif, Herianto Politeknik Negeri Media Kreatif, Universitas Gadjah Mada Abstract Keywords: 3D Printing, under extrusion layer, warping, visual, nozzle Share Link | Plain Format | Corresponding Author (Cholid Mawardi)

141	Materials Science	ABS-229
Preparation and characterization of cellulose nanofibers from oil palm fronds by chemical-mechanical treatment Randis Randis (a*), Femiana Gapsari (b) (a) Department of Mechanical Engineering, Balikpapan State Polytechnic, Soekarno Hatta St. Km. 8, Balikpapan 76126, Indonesia *randis[at]poltekba.ac.id (b) Department of Mechanical Engineering, Faculty of Engineering, Brawijaya University, MT Haryono 167, Malang 65145, Indonesia Abstract Keywords: Cellulose nanofibrils- Oil palm frond fibers- Chemical-mechanical treatment- Crystallinity index- Thermal stability Share Link | Plain Format | Corresponding Author (Randis randis)

142	Materials Science	ABS-241
Comparative Analysis of Flexural Strengthening for Reinforced Concrete Beams Using Single and Double Line of FRP Plates Sifa Ulhaq Nadila 1, a) Riawan Gunadi 1,b) Department of Civil Engineering, Applied Master of Infrastructure Engineering, Politeknik Negeri Bandung, 40559 West Bandung, Indonesia Abstract Keywords: Structural Strengthening, Reinforced Concrete Beams, FRP (Fiber Reinforced Polymer) Plates Share Link | Plain Format | Corresponding Author (Sifa Nadila)

143	Materials Science	ABS-248
EXPERIMENTAL STUDY OF FANR AS A CEMENT REPLACEMENT IN THE PROPERTIES OF MORTAR Rizal Syahyadi, Taufiq Saidi, Muttaqin Hasan, Akhyar, Amir Fauzi, and Aulia Rachman Doctoral Program, School of Engineering, Post Graduate Program, Universitas Syiah Kuala, Acheh, Indonesia Civil Engineering Department, Politeknik Negeri Lhokseumawe, Acheh, Indonesia Civil Engineering Department, Universitas Syiah Kuala, Acheh, Indonesia Mechanical Engineering Department, Universitas Syiah Kuala, Acheh, Indonesia Civil Engineering Department, Universitas Malikussaleh, Acheh, Indonesia Geopolymer and Green Technology Research Centre, Acheh, Indonesia Abstract The material of FANR is a waste material from the power plantation of Nagan Raya, Acheh, Indonesia. Some information recorded that the particle of FANR had the chemical content of Si, Fe, Al, and, Ca with the misty surface. However, the misty surface of FANR suspected to influence the properties of mortar. So, this study aimed to evaluate the use of FANR as a cement replacement in the properties of mortar. The investigation was conducted with the FANR of 5%, 10%, 15%, 20%, and 25%, respectively with the water to cement ratio of o.55 and 0.50, respectively. The parameter in this study included chemical composition, workability, setting time, and compressive strength. The results showed that the FANR had a chemical composition of Si, Fe, Al, and Ca with the particle shape of sphere and misty surface. Due to these characteristics, the FANR had a decreased workability and shorter the setting time in the fresh mortar. Finally, the 5% FANR with w/c ratio of 0.50 provided the highest compressive strength at 28 days. Whereas, the use of FANR with more percentage was considered to improve the compressive strength after 28 days. It concluded that the use of FANR as a cement replacement affected on the properties of mortar. Keywords: Chemical content, workability, setting time, compressive strength Share Link | Plain Format | Corresponding Author (Rizal Syahyadi)

144	Materials Science	ABS-254
Analysis of Light Mortar Compressive Strength Test with The Addition of Bottom Ash Mixture as A Fine Aggregate Substitution Dedi Enda, Roma Dearni, and Dewita Mahrani Civil Engineering Department Politeknik of Bengkalis, Bengkalis, Indonesia Abstract Bottom ash, categorized as non-b3 waste, resembles coarse grains and is used as a substitute for sand in lightweight mortar, affecting its physical properties. This experimental research aims to compare mortars 1PC : 1PS, will determine the compressive strength of lightweight mortar for use on wall elementsprecast with the addition of a mixture of coal waste (bottom ash) as an aggregate substitute fine. This research compares the compressive strength of lightweight mortars using varying percentages (25%, 50%, 75%) of bottom ash and different foam contents (30%, 50%). Results indicate that the density of the mortars ranges from 925.95 to 1467.49 kg/m3, with optimal compressive strength occurring at 25%-50% bottom ash and 50% foaming agent, yielding quality increases of 99.55% and 89.73% compared to no bottom ash. Keywords: bottom ash, foaming agent, foam, sand, lightweight mortar Share Link | Plain Format | Corresponding Author (Dedi Enda)

145	Natural resources management	ABS-10
CHEMICAL CHARACTERISTICS AND PREFERENCES OF PANELLIST TOWARDS LACTATE-FERMENTED ARABICA COFFEE Tri Hariyadi, Salsabila Hayyida, Deva Azzahra, Bevi Lidya Chemical Engineering Department, Politeknik Negeri Bandung, Indonesia Abstract This study aims to assess the impact of postharvest processing methods on lactate-fermented Arabica coffee chemical characteristics and panellist preferences. After lactate fermentation, the beans were processed with different methods: honey and full-washed, followed by medium roasting and grinding. The full-washed approach yielded green beans with a moisture level of 12.37% d/b, higher than the honey method^s 6.38% d/b. After roasting, full washed processed beans had a moisture content of 2.04% d/b, whereas honey processed beans had a greater moisture content of 2.57% d/b. The green beans that were processed with honey had the highest caffeine level, measuring 0.110 % d/b, whereas the full-washed-processed beans had a caffeine value of 0.053% d/b. However, following roasting, the full washed processed beans had a greater caffeine concentration (0.160% d/b) than the honey processed beans (0.134% d/b). There was no significant difference in pH values between the methods, either in green beans or roasted beans, which ranged from 4.0 to 4.2. The coffee grind from both methods was then mixed for a panellist preference test. The results showed the panellists preferred coffee with a higher proportion of honey processed coffee. Keywords: arabica coffee, fermentation, full-washed, honey, lactic-acid Share Link | Plain Format | Corresponding Author (Tri Hariyadi)

146	Natural resources management	ABS-42
Utilization of Ergo-Aesthetic Model in the Development of Rattan Bag Handicraft Products Dwi Cahyadi (a,b*), Siti Haida Ismail (b), Mohd Yusof MD Daud (b), Roslina Mohammad (b), and Muh Irwan (c) a) Razak Faculty of Technology and Informatics, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia b) Department of Design, Politeknik Negeri Samarinda, Samarinda, Indonesia *dwicahyadi[at]polnes.ac.id c) Department of Chemical Engineering, Politeknik Negeri Samarinda, Samarinda, Indonesia Abstract Indonesia is a producer of 70-80% of rattan in the world and one of the uses of this non-timber forest product is rattan bag handicraft products. Products made from rattan have existed since ancient times as a functional product for storing hunting products or for gardening. The increasing interest in handicrafts from young people for handicraft products makes the handicraft industry must follow the trend and function of rattan bags as a fashion product at this time. This research aims to develop women^s handicraft products from rattan materials using the Vinod Goel design method combined with the analysis of the ergo-aesthetic model. The result of this design is a women^s bag product made of rattan with a combination of wood, cowhide, and doyo weaving. The products produced follow the ergo-aesthetic model, which is a product that is comfortable to use and has an element of beauty from the use of a combination of natural ingredients. The contribution of this research is to provide recommendations to the rattan bag handicraft industry to innovate products by applying an ergo-aesthetic model in making the development of rattan bag products that are suitable as fashion products today. Keywords: Ergo-aesthetic, Handicrafts, rattan bags Share Link | Plain Format | Corresponding Author (Dwi Cahyadi)

147	Natural resources management	ABS-119
The Influence of Brand Trust and Extraversion on Brand Evangelism at Shopee Heldina Pristanti (a), Andi Nurhasanah (b), Satryawati (c), Citra Nur Aziza (d) a. Politeknik Negeri Samarinda, Jl. Cipto Mangunkusumo Kampus Gunung Panjang, Sungai Keledang, Kec. Samarinda Seberang, Kota Samarinda, Kalimantan Timur 75242 b. Politeknik Negeri Samarinda, Jl. Cipto Mangunkusumo Kampus Gunung Panjang, Sungai Keledang, Kec. Samarinda Seberang, Kota Samarinda, Kalimantan Timur 75242 c. Politeknik Negeri Samarinda, Jl. Cipto Mangunkusumo Kampus Gunung Panjang, Sungai Keledang, Kec. Samarinda Seberang, Kota Samarinda, Kalimantan Timur 75242 Abstract Abstract. This study investigates the influence of brand trust and extraversion on brand evangelism partially and simultaneously, specifically within the context of Shopee users in Samarinda. A quantitative methodology was employed, utilizing a purposive sampling technique to select 100 respondents through onlien questionnaire. The results reveal that both brand trust and extraversion have a significant positive impact on brand evangelism individually and simultaneously. These findings underscore the importance of fostering brand trust and considering personality traits such as extraversion in promoting brand advocacy behaviours among consumers. Keywords: Brand Trust, Extraversion, Brand Evangelism Keywords: Brand Trust, Extraversion, Brand Evangelism Share Link | Plain Format | Corresponding Author (Heldina Pristanti)

148	Natural resources management	ABS-125
The Role of Social Influence, COOI, Consumer Ethnocentrism, and Consumer Animosity in Shaping Purchase Decisions among Z-generation MIXUE Consumers in Indonesia Della Olivia Caterina Kalangit1, Hendrik Batoteng2, Suramli3, Kristin Wulansari4 and Vina Ulandari5 Politeknik Negeri Samarinda Abstract This research was conducted based on the phenomenon of the success of MIXUE business management in exploring various market points, one of which is in Indonesia. However, this does not have any implications for Z Generation as customers to purchase these products. Generation Z does not consider the sense of love and pride for other similar products that come from their own country. The dominance of the Z-generation with its characteristics that are quite different from previous generations provides many perspectives to uncover the truth. This study uses a survey method with a sample size of 180 Z-generation consumers spread across Indonesia which was randomly obtained by an accidental purposive random sampling technique. The data collected from respondents (primary data) was tabulated and tested using statistical methods which were then analyzed. The research results conducted with the analysis tool SEM (structural equation modelling) AMOS version 23 show that social influence and country of origin image have a positive and significant impact on product judgment. Furthermore, consumer ethnocentrism and consumer animosity have a negative and significant impact on purchase intention. Then, social influence and product judgment have a positive and significant impact on purchase intention. Finally, social influence, product judgment, and purchase intention have a positive and significant impact on the purchase decision of Z-generation MIXUE consumers in Indonesia. Keywords: Social Influence, Country of Origin Image, Consumer Ethnocentrism, Consumer Animosity, Z-generation Consumer Behavior Share Link | Plain Format | Corresponding Author (Della Olivia Caterina Kalangit)

149	Natural resources management	ABS-152
Comparison of the Quality of Red Bricks Made with Kaolin and Bauxite Tailings Sartika, Syarifah Aqla Politeknik Negeri ketapang Abstract West Borneo Province has the largest kaolin resources in Indonesia, with around 359 million tons spread across several regencies, including Ketapang Regency. Similarly, the largest bauxite resources in Indonesia are also found in West Borneo Province, with approximately 655 million tons concentrated in Ketapang Regency. Bauxite processing involves washing, which produces a residue in the form of fine mud or clay, known as bauxite tailings. As the volume of tailings from bauxite beneficiation increases, there has been growing attention towards their management. Kaolin is a natural mining material that is white, brittle, non-plastic, and categorized as a type of clay. Clay is commonly used as a raw material in the production of red bricks, roof tiles, and ceramics. The abundance of these resources in Ketapang Regency led to research comparing the quality of red bricks made with kaolin and bauxite tailings. The red bricks were assessed based on the quality standards outlined in SNI 15-2094-2000, with a focus on compressive strength tests. Based on the compressive strength tests, red bricks made with bauxite tailings at compositions of 0%, 20%, and 40% achieved compressive strength values of 3.569 MPa, 4.397 MPa, and 5.610 MPa, respectively. In contrast, kaolin-based red bricks with kaolin compositions of 0%, 20%, and 40% achieved compressive strength values of 3.569 MPa, 4.570 MPa, and 5.728 MPa, respectively. Both the 40% tailings and 40% kaolin compositions meet the SNI standard for compressive strength, which requires a minimum value of 5 MPa. This indicates that the compressive strength characteristics of red bricks made from bauxite tailings and kaolin are similar. Additionally, increasing the proportion of kaolin or tailings in red bricks enhances their compressive strength. Therefore, it can be concluded that bauxite tailings can be effectively used as a mixture in red brick production with a composition of 40%. Keywords: Red Bricks, Kaolin, Bauxite Tailings Share Link | Plain Format | Corresponding Author (Sartika Sartika)

150	Natural resources management	ABS-166
Exploring the Impact of Store Attributes on Customer Loyalty: The Role of Impulsive Buying and Satisfaction at Miniso Indonesia Sarwo Eddy Wibowo , Sugeng Hariyadi , Anggun Regeta Sari , Bela Barus , Suminto , Politeknik Negeri Samarinda Abstract This research aims to analyze and prove the influence of store atmosphere, store image, product variety, and place on repeat buying through impulsive buying and satisfaction among Miniso visitors in Indonesia. this research uses the SEM (structural equation modelling) model. A sample of 165 people was taken online and offline with a likert scale of 1-5. This research carried out validity and reliability tests using IBM SPSS statistics 23 software and structural model fit tests using the IBM AMOS version 23 software. the results of this research test show that store image and place do not have a significant effect on impulsive buying. store atmosphere has no significant effect on the brand repeat buying. store atmosphere and product variety have a significant effect on impulsive buying. store atmosphere, store image, product variety, and place significantly affect satisfaction. brand satisfaction has a significant influence on repeat buying. store image, product variety, and place have a significant effect on repeat buying for Miniso visitors in Indonesia. Keywords: Store atmosphere, store image, product variety, place, Impulsive Buying. Satisfaction, and Repeat Buying Share Link | Plain Format | Corresponding Author (Sarwo Eddy Wibowo)

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