1.
Yanuar Haryanto; Nanang Gunawan Wariyatno; Fu-Pei Hsiao; Hsuan-Teh Hu; Ay Lie Han; Laurencius Nugroho; Hioe Hartono
RC T-beams with flexural strengthening in the negative moment region under different configurations of NSM CFRP rods Journal Article
In: Engineering Failure Analysis, vol. 173, 2025.
@article{nokey,
title = {RC T-beams with flexural strengthening in the negative moment region under different configurations of NSM CFRP rods},
author = {Yanuar Haryanto and Nanang Gunawan Wariyatno and Fu-Pei Hsiao and Hsuan-Teh Hu and Ay Lie Han and Laurencius Nugroho and Hioe Hartono },
url = {https://www.sciencedirect.com/science/article/abs/pii/S1350630725001992?via%3Dihub},
doi = {10.1016/j.engfailanal.2025.109458},
year = {2025},
date = {2025-02-27},
journal = {Engineering Failure Analysis},
volume = {173},
abstract = {This study employed a near-surface mounted (NSM) technique to enhance the flexural performance of reinforced concrete (RC) T-beams in the negative moment region, using carbon fiber reinforced polymer (CFRP) rods embedded at varying depths. An experimental investigation was conducted, supported by analytical calculations and finite element (FE) simulations, to validate the results. The experiments revealed that beams with half-embedded CFRP rods experienced partial debonding at significant crack locations, a problem potentially mitigated by fully embedded rods. Strengthening with NSM-CFRP rods increased cracking, yield, and ultimate loads by 10–21%, 36–38%, and 30–40%, respectively, compared to control beams, while also enhancing stiffness. However, these methods may have a twofold impact on the specimen by decreasing its ductility and energy absorption capacity. The analytical approach provided accurate and conservative predictions, with a coefficient of variation of 4.5%, while the FE model demonstrated high accuracy, achieving a coefficient of variation of 3.5% when compared to experimental flexural load capacity results.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This study employed a near-surface mounted (NSM) technique to enhance the flexural performance of reinforced concrete (RC) T-beams in the negative moment region, using carbon fiber reinforced polymer (CFRP) rods embedded at varying depths. An experimental investigation was conducted, supported by analytical calculations and finite element (FE) simulations, to validate the results. The experiments revealed that beams with half-embedded CFRP rods experienced partial debonding at significant crack locations, a problem potentially mitigated by fully embedded rods. Strengthening with NSM-CFRP rods increased cracking, yield, and ultimate loads by 10–21%, 36–38%, and 30–40%, respectively, compared to control beams, while also enhancing stiffness. However, these methods may have a twofold impact on the specimen by decreasing its ductility and energy absorption capacity. The analytical approach provided accurate and conservative predictions, with a coefficient of variation of 4.5%, while the FE model demonstrated high accuracy, achieving a coefficient of variation of 3.5% when compared to experimental flexural load capacity results.
2.
Muhammad Farhan; Han Ay Lie; Purwanto; Bonaventura Harimurti W. Hadikusumo
Mechanical And Physical Behavior Of Self-healing Concrete Using Bacillus Megaterium Bacteria Journal Article
In: International Journal of GEOMATE, vol. 28, no. 125, pp. 83-91, 2025, ISSN: 2186-2982 .
@article{nokey,
title = {Mechanical And Physical Behavior Of Self-healing Concrete Using Bacillus Megaterium Bacteria },
author = {Muhammad Farhan and Han Ay Lie and Purwanto and Bonaventura Harimurti W. Hadikusumo},
url = {https://geomatejournal.com/geomate/article/view/4715/3551},
issn = { 2186-2982 },
year = {2025},
date = {2025-01-17},
journal = {International Journal of GEOMATE},
volume = {28},
number = {125},
pages = {83-91},
abstract = {The Bacillus megaterium bacteria synergy on concrete mechanical and physical properties to enhance durability and strength through self-healing is studied. Two Bacillus megaterium concentration variations, variations of 4% and 8% to water volume, were added to fresh concrete based on the substitution method. NC0 stands for 0% bacteria and functions as a control specimen, while SHC4 and SHC8 represented 4% and 8% bacteria content, respectively. The primary focus was to analyze the compressive strength, density, permeable voids, and water absorption behavior at ages 28 and 56 days. Results indicated that the bacteria significantly improved the mechanical properties of hardened concrete. SHC4 and SHC8 exhibited a compressive strength increase of 8% and 14% at 28 days and 15% and 19% at 56 days compared to NC0. This strength increase resulted from permeable voids and water absorption reduction, as well as an improved aggregate-to-mortar ITZ bond due to the formation of bacteria-produced CaCO3, which filled the voids. Reduction in permeable voids and water absorption were 7% to 17%, while density improvement was up to 10% at 28 days. A higher bacteria content consequently produced a better void-filling mechanism. The SHC8 with 8% Bacillus megaterium was proven more effective than SHC4. The 56-day specimens revealed that a significant concrete performance enhancement resulted from the development of CaCO3 deposits over time. It is interesting for further studies to determine the bacteria effectiveness convergence as a function of hardening time. This research highlights the potential of biological approach methods for developing sustainable and resilient construction materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The Bacillus megaterium bacteria synergy on concrete mechanical and physical properties to enhance durability and strength through self-healing is studied. Two Bacillus megaterium concentration variations, variations of 4% and 8% to water volume, were added to fresh concrete based on the substitution method. NC0 stands for 0% bacteria and functions as a control specimen, while SHC4 and SHC8 represented 4% and 8% bacteria content, respectively. The primary focus was to analyze the compressive strength, density, permeable voids, and water absorption behavior at ages 28 and 56 days. Results indicated that the bacteria significantly improved the mechanical properties of hardened concrete. SHC4 and SHC8 exhibited a compressive strength increase of 8% and 14% at 28 days and 15% and 19% at 56 days compared to NC0. This strength increase resulted from permeable voids and water absorption reduction, as well as an improved aggregate-to-mortar ITZ bond due to the formation of bacteria-produced CaCO3, which filled the voids. Reduction in permeable voids and water absorption were 7% to 17%, while density improvement was up to 10% at 28 days. A higher bacteria content consequently produced a better void-filling mechanism. The SHC8 with 8% Bacillus megaterium was proven more effective than SHC4. The 56-day specimens revealed that a significant concrete performance enhancement resulted from the development of CaCO3 deposits over time. It is interesting for further studies to determine the bacteria effectiveness convergence as a function of hardening time. This research highlights the potential of biological approach methods for developing sustainable and resilient construction materials.
3.
Bobby Rio Indriyantho; Joko Purnomo; Purwanto; Marc Ottele; Ay Lie Han; Buntara Sthenly Gan
Multicriteria Sensitivity Analysis for Numerical Model Validation of Experimental Data Journal Article
In: International Journal of Technology (IJTech) , vol. 15, no. 6, 2024.
@article{nokey,
title = {Multicriteria Sensitivity Analysis for Numerical Model Validation of Experimental Data},
author = {Bobby Rio Indriyantho and Joko Purnomo and Purwanto and Marc Ottele and Ay Lie Han and Buntara Sthenly Gan
},
url = {https://ijtech.eng.ui.ac.id/article/view/7146#abstract},
year = {2024},
date = {2024-11-01},
journal = {International Journal of Technology (IJTech) },
volume = {15},
number = {6},
abstract = {Sensitivity analysis is a decisive step in experimental and numerical structural mechanics. The analysis of structural model quantifies the importance of each input parameter, potential interaction and effects on structural response. Therefore, this study aimed to help reduce the uncertainty surrounding major variables, providing valuable guidance for conducting future experiments. During the investigation, numerically deterministic sensitivity analysis based on multicriteria model evaluations of load-displacement curves representing actual behavior of the member correctly, were reviewed. Multicriteria model combined the evaluation of peak load, energy dissipation before ultimate loading, and toughness of load-displacement response. The methodology led to a strong sensitivity analysis method, generating an agreement between numerical and experimental responses. Moreover, an investigation of the method was presented for a geopolymer haunch, the numerical model was based on rigid body spring model (RBSM), which enabled precise behavior simulation of reinforced concrete structures. RBSM was refined, enabling in-depth evaluation of stress-strain contours, plasticity index, initial crack formation and crack propagation, as well as RBSM-spring failure modes. The proposed multicriteria sensitivity analysis can be implemented with other simulation methods, such as finite element analysis (FEA) and structural simulation software. The recommended method is applicable to any structural member, where laboratory-tested full-scale specimens were functioning as validation tools. Following the proposed multicriteria sensitivity analysis, experimental load-displacement curves of this study supported the results of numerical RBSM in an acceptable range of error predictions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Sensitivity analysis is a decisive step in experimental and numerical structural mechanics. The analysis of structural model quantifies the importance of each input parameter, potential interaction and effects on structural response. Therefore, this study aimed to help reduce the uncertainty surrounding major variables, providing valuable guidance for conducting future experiments. During the investigation, numerically deterministic sensitivity analysis based on multicriteria model evaluations of load-displacement curves representing actual behavior of the member correctly, were reviewed. Multicriteria model combined the evaluation of peak load, energy dissipation before ultimate loading, and toughness of load-displacement response. The methodology led to a strong sensitivity analysis method, generating an agreement between numerical and experimental responses. Moreover, an investigation of the method was presented for a geopolymer haunch, the numerical model was based on rigid body spring model (RBSM), which enabled precise behavior simulation of reinforced concrete structures. RBSM was refined, enabling in-depth evaluation of stress-strain contours, plasticity index, initial crack formation and crack propagation, as well as RBSM-spring failure modes. The proposed multicriteria sensitivity analysis can be implemented with other simulation methods, such as finite element analysis (FEA) and structural simulation software. The recommended method is applicable to any structural member, where laboratory-tested full-scale specimens were functioning as validation tools. Following the proposed multicriteria sensitivity analysis, experimental load-displacement curves of this study supported the results of numerical RBSM in an acceptable range of error predictions.
4.
Yanuar Haryanto; Gathot Heri Sudibyo; Laurencius Nugroho; Hsuan-Teh Hu; Ay Lie Han; Fu-Pei Hsiao; Arnie Widyaningrum; Yudi Susetyo
In: Sage Journals, 2024.
@article{nokey,
title = {Flexural performance of the negative moment region in bonded steel-wire-rope-strengthened reinforced concrete T-beams at different prestressing levels},
author = {Yanuar Haryanto and Gathot Heri Sudibyo and Laurencius Nugroho and Hsuan-Teh Hu and Ay Lie Han and Fu-Pei Hsiao and Arnie Widyaningrum and Yudi Susetyo},
url = {https://journals.sagepub.com/doi/10.1177/13694332241268186},
doi = {10.1177/13694332241268186},
year = {2024},
date = {2024-07-30},
journal = {Sage Journals},
abstract = {This work examines the performance of reinforced concrete (RC) beams strengthened using bonded steel wire rope (SWR) at various prestressing levels. The strengthening approach has, however, been applied to the flexural strengthening of RC T-beams in the negative moment region, in order to determine its advantages. For this purpose, four RC T-beams were fabricated and tested under monotonic four-point bending: one control beam (S00), one beam strengthened with non-prestressed SWR (S20), and two beams strengthened with SWR (prestressed at 10% and 20% of their ultimate tensile strength: S21 and S22). The results indicate that the strengthened beams exhibit higher load-carrying capacities. Specifically, the cracking load, yield load, and ultimate load of S20, S21, and S22 increase by 10%–30%, 30%–50%, and 50%–90%, respectively, compared to S00. Additionally, there is an improvement in stiffness and energy absorption capacity. However, these strategies may have a dual effect on the specimens, resulting in a reduction in their ductility index. Finally, the tested beams were replicated using a three-dimensional finite element model, which has proved effective in predicting the behavior of such structures and, therefore, was found to be appropriate for use in future studies.
},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This work examines the performance of reinforced concrete (RC) beams strengthened using bonded steel wire rope (SWR) at various prestressing levels. The strengthening approach has, however, been applied to the flexural strengthening of RC T-beams in the negative moment region, in order to determine its advantages. For this purpose, four RC T-beams were fabricated and tested under monotonic four-point bending: one control beam (S00), one beam strengthened with non-prestressed SWR (S20), and two beams strengthened with SWR (prestressed at 10% and 20% of their ultimate tensile strength: S21 and S22). The results indicate that the strengthened beams exhibit higher load-carrying capacities. Specifically, the cracking load, yield load, and ultimate load of S20, S21, and S22 increase by 10%–30%, 30%–50%, and 50%–90%, respectively, compared to S00. Additionally, there is an improvement in stiffness and energy absorption capacity. However, these strategies may have a dual effect on the specimens, resulting in a reduction in their ductility index. Finally, the tested beams were replicated using a three-dimensional finite element model, which has proved effective in predicting the behavior of such structures and, therefore, was found to be appropriate for use in future studies.
5.
Henda Febrian Egatama; Nanang Gunawan Wariyatno; Han Ay Lie; Muhammad Zulfikar Adhi Muliawan; Buntara Shently Gan
Quantitative Shaking Evaluation of Bracing-Strengthened and Base-Isolated Buildings Using Seismic Intensity Level Journal Article
In: Proceeding of Engineering and Technology Innovation (PETI), vol. 27, 2024.
@article{nokey,
title = {Quantitative Shaking Evaluation of Bracing-Strengthened and Base-Isolated Buildings Using Seismic Intensity Level },
author = {Henda Febrian Egatama and Nanang Gunawan Wariyatno and Han Ay Lie and Muhammad Zulfikar Adhi Muliawan and Buntara Shently Gan},
url = {https://ojs.imeti.org/index.php/PETI/article/view/13578},
doi = {10.46604/peti.2024.13578 },
year = {2024},
date = {2024-06-30},
journal = {Proceeding of Engineering and Technology Innovation (PETI)},
volume = {27},
abstract = {In current design practice, the seismic strength design of buildings is commonly based on the strength concept, lacking a quantitative evaluation tool that can show the performance of the buildings during earthquakes. This paper demonstrates the application of seismic intensity level (SIL) as a quantitative evaluation tool for aseismic building performance. A simulation test is conducted on three categories of building-frame: non-strengthened (NA), bracing-strengthened (BS), and base-isolated (BI), subjected to a north-south (N-S) 1940 El Centro seismic wave. The criteria evaluated include maximum acceleration, energy dissipation, and the measured seismic intensity level (m-SIL). The effect of strengthening methods is compared based on those criteria. The results show that despite the apparent reduction in structural response metrics, the SIL value diminishes more substantially for base isolators (4.5 level decrease) than bracing (0.4 level decrease). This confirms that SIL provides higher consistency results and is straightforward to comprehend.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In current design practice, the seismic strength design of buildings is commonly based on the strength concept, lacking a quantitative evaluation tool that can show the performance of the buildings during earthquakes. This paper demonstrates the application of seismic intensity level (SIL) as a quantitative evaluation tool for aseismic building performance. A simulation test is conducted on three categories of building-frame: non-strengthened (NA), bracing-strengthened (BS), and base-isolated (BI), subjected to a north-south (N-S) 1940 El Centro seismic wave. The criteria evaluated include maximum acceleration, energy dissipation, and the measured seismic intensity level (m-SIL). The effect of strengthening methods is compared based on those criteria. The results show that despite the apparent reduction in structural response metrics, the SIL value diminishes more substantially for base isolators (4.5 level decrease) than bracing (0.4 level decrease). This confirms that SIL provides higher consistency results and is straightforward to comprehend.
6.
Henda Febrian Egatama; Bobby Rio Indriyantho; Ay Lie Han; Eiji Nouchi; Emy Shinta Wijayaningsih; Buntara Sthenly Gan
Quantification of Shaking-based Criteria for Evaluating Aseismic Performance of House and Building Journal Article
In: Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2024.
@article{nokey,
title = {Quantification of Shaking-based Criteria for Evaluating Aseismic Performance of House and Building},
author = {Henda Febrian Egatama and Bobby Rio Indriyantho and Ay Lie Han and Eiji Nouchi and Emy Shinta Wijayaningsih and Buntara Sthenly Gan },
url = {https://link.springer.com/article/10.1007/s40996-024-01411-y},
doi = {https://doi.org/10.1007/s40996-024-01411-y},
year = {2024},
date = {2024-04-17},
journal = {Iranian Journal of Science and Technology, Transactions of Civil Engineering},
abstract = {Based on the 22-year (1996–2018) Japan Meteorological Agency periodical data, the number of human injuries exceeded those deaths due to earthquakes. Similarly, the number of collapsed houses number and buildings is below the number of partly damaged ones. Investigations showed that the cause of human casualties was shaking when strong earthquakes occurred. The collapse of non-structural components, bookcases, machinery equipment, or ceilings as a result of severe shaking is the primary cause of human mortality. The report indicates that the houses and buildings designed by the up-to-date seismic code revisions show adequate resistance against the earthquake. However, the latest codes fail to protect the human casualties inside the houses and buildings. Present works proposed quantifying shaking-based criteria for evaluating houses and buildings’ seismic intensity scale (SIS). Using SIS could benefit the designer in selecting the appropriate aseismic methods. This SIS-based criterion is verified by evaluating a 5-story earthquake-proof frame structure equipped with two aseismic devices. The results show that the maximum acceleration reduction was 77.7% and 88.6% for a frame with a tuned mass damper (TMD) and a base isolator (BI) consecutively. The decrease in SIS number for a frame with BI is more significant compared to TMD. The study concluded that BI is more effective than TMD in reducing the shaking of houses and buildings. The objective of SIS computing is to find measures or actions that can minimize the risk of human casualties and evaluate the best performances of aseismic devices in houses and buildings during earthquakes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Based on the 22-year (1996–2018) Japan Meteorological Agency periodical data, the number of human injuries exceeded those deaths due to earthquakes. Similarly, the number of collapsed houses number and buildings is below the number of partly damaged ones. Investigations showed that the cause of human casualties was shaking when strong earthquakes occurred. The collapse of non-structural components, bookcases, machinery equipment, or ceilings as a result of severe shaking is the primary cause of human mortality. The report indicates that the houses and buildings designed by the up-to-date seismic code revisions show adequate resistance against the earthquake. However, the latest codes fail to protect the human casualties inside the houses and buildings. Present works proposed quantifying shaking-based criteria for evaluating houses and buildings’ seismic intensity scale (SIS). Using SIS could benefit the designer in selecting the appropriate aseismic methods. This SIS-based criterion is verified by evaluating a 5-story earthquake-proof frame structure equipped with two aseismic devices. The results show that the maximum acceleration reduction was 77.7% and 88.6% for a frame with a tuned mass damper (TMD) and a base isolator (BI) consecutively. The decrease in SIS number for a frame with BI is more significant compared to TMD. The study concluded that BI is more effective than TMD in reducing the shaking of houses and buildings. The objective of SIS computing is to find measures or actions that can minimize the risk of human casualties and evaluate the best performances of aseismic devices in houses and buildings during earthquakes.
7.
Ay Lie Han; Bobby Rio Indriyantho; Mhd Rony Asshidiqie; Purwanto; Widowati; Kartono; I Nyoman Jujur
Fracture Behavior of Crop Circle Ceramic Tiles: Experimental and Numerical Study Journal Article
In: International Journal of Engineering and Technology Innovation, vol. 14, no. 2, 2024.
@article{nokey,
title = {Fracture Behavior of Crop Circle Ceramic Tiles: Experimental and Numerical Study },
author = {Ay Lie Han and Bobby Rio Indriyantho and Mhd Rony Asshidiqie and Purwanto and Widowati and Kartono and I Nyoman Jujur},
url = {https://ojs.imeti.org/index.php/IJETI/article/view/13070},
doi = {https://doi.org/10.46604/ijeti.2024.13070 },
year = {2024},
date = {2024-03-27},
urldate = {2024-03-27},
journal = {International Journal of Engineering and Technology Innovation},
volume = {14},
number = {2},
abstract = {This research investigates the effect of three-dimensional (3D) bee-crop-circle tiles on load deformation, initial cracking and propagation, and stress redistribution. Experimental tests provide limited data due to the small specimen size and brittle nature of the material. A finite element (FE) model is constructed and validated by laboratory data to analyze the stress-strain responses and failure mode. The model enables a detailed description of stress patterns, stress propagation, and redistribution of layers beneath the bee design. The study concludes that a 3D crop circle-inspired design significantly influences the ultimate load-carrying capacity and stress-related behavior. The load-deformation response is nonlinear, and the coloring influences the thickness of coatings, further affecting the ultimate load and initial stiffness. Furthermore, designs with convex details result in an arc action, deviating the stress concentrations away from the line of loading. The FE model slightly overestimates the initial stiffness but represents the ultimate load and load-displacement response with high accuracy.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This research investigates the effect of three-dimensional (3D) bee-crop-circle tiles on load deformation, initial cracking and propagation, and stress redistribution. Experimental tests provide limited data due to the small specimen size and brittle nature of the material. A finite element (FE) model is constructed and validated by laboratory data to analyze the stress-strain responses and failure mode. The model enables a detailed description of stress patterns, stress propagation, and redistribution of layers beneath the bee design. The study concludes that a 3D crop circle-inspired design significantly influences the ultimate load-carrying capacity and stress-related behavior. The load-deformation response is nonlinear, and the coloring influences the thickness of coatings, further affecting the ultimate load and initial stiffness. Furthermore, designs with convex details result in an arc action, deviating the stress concentrations away from the line of loading. The FE model slightly overestimates the initial stiffness but represents the ultimate load and load-displacement response with high accuracy.
8.
Dinar Gumilang Jati; Joko Purnomo; Buntara S. Gan; Lintang B. Leksono; Ay Lie Han
Normal tensile bond behaviour of CFRP-epoxy laminate to concrete and steel Journal Article
In: International Journal of Adhesion and Adhesives, vol. 132, 2024.
@article{nokey,
title = {Normal tensile bond behaviour of CFRP-epoxy laminate to concrete and steel},
author = {Dinar Gumilang Jati and Joko Purnomo and Buntara S. Gan and Lintang B. Leksono and Ay Lie Han
},
url = {https://www.sciencedirect.com/science/article/abs/pii/S0143749624000654?via%3Dihub},
doi = {https://doi.org/10.1016/j.ijadhadh.2024.103683},
year = {2024},
date = {2024-03-19},
journal = {International Journal of Adhesion and Adhesives},
volume = {132},
abstract = {The effectiveness of CFRP sheets as external concrete reinforcement is determined by the CFRP-concrete bond behaviour. In this study the normal tensile bond of CFRP-epoxy laminate was assessed through the behaviour of the CFRP-concrete, and CFRP-steel bond. A pull-off apparatus combined with a newly introduced method using a clip-on displacement transducer was employed. The specimen was a field-impregnated single CFRP sheet attached to concrete and steel. The contribution of the epoxy was tested individually. The load-displacement behaviour, the ultimate strength, failure mode and the individual component's contribution to the CFRP bond, were analysed. The study concluded that for a concrete compression strength as high as 50 MPa the failure was designated by concrete rupture. For the CFRP-steel specimens, the failure was distinguished as adhesive interface failure or CFRP failure, influenced by the degree of epoxy impregnation and steel surface preparation. The load-displacement behaviour of the CFRP-concrete, CFRP-steel and epoxy were characterized by non-linearity with no post peak. The presence of CFRP sheets enhanced the stiffness of the individual epoxy. The presence of CFRP-epoxy has a negative affected to the normal tensile stiffness of concrete, but postponed the load levels at which first concrete cracking occur, regardless the concrete compression strength.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The effectiveness of CFRP sheets as external concrete reinforcement is determined by the CFRP-concrete bond behaviour. In this study the normal tensile bond of CFRP-epoxy laminate was assessed through the behaviour of the CFRP-concrete, and CFRP-steel bond. A pull-off apparatus combined with a newly introduced method using a clip-on displacement transducer was employed. The specimen was a field-impregnated single CFRP sheet attached to concrete and steel. The contribution of the epoxy was tested individually. The load-displacement behaviour, the ultimate strength, failure mode and the individual component's contribution to the CFRP bond, were analysed. The study concluded that for a concrete compression strength as high as 50 MPa the failure was designated by concrete rupture. For the CFRP-steel specimens, the failure was distinguished as adhesive interface failure or CFRP failure, influenced by the degree of epoxy impregnation and steel surface preparation. The load-displacement behaviour of the CFRP-concrete, CFRP-steel and epoxy were characterized by non-linearity with no post peak. The presence of CFRP sheets enhanced the stiffness of the individual epoxy. The presence of CFRP-epoxy has a negative affected to the normal tensile stiffness of concrete, but postponed the load levels at which first concrete cracking occur, regardless the concrete compression strength.
9.
Mochammad Qomaruddin; Han Ay Lie; Purwanto; Widayat
Chemical and Microstructural Changes in Reclaimed Asphalt Pavement Aggregates by Pyrolysis Journal Article
In: Arabian Journal for Science and Engineering, 2024.
@article{nokey,
title = {Chemical and Microstructural Changes in Reclaimed Asphalt Pavement Aggregates by Pyrolysis},
author = {Mochammad Qomaruddin and Han Ay Lie and Purwanto and Widayat},
url = {https://link.springer.com/journal/13369},
year = {2024},
date = {2024-01-25},
urldate = {2024-01-25},
journal = { Arabian Journal for Science and Engineering},
abstract = {The utilization of reclaimed asphalt pavement (RAP) aggregates as an alternative for rigid pavements is limited. The main objective of this study is to explore and improve the utilization of RAP aggregates as an alternative material for rigid pavement. Specifically, this study focuses on addressing a significant challenge associated with RAP aggregates, which is their poor bond with cementitious binders. The poor bonding results in low compressive and tensile strengths of concrete or mortar. The poor bonding is mainly due to the presence of a thin oily layer of asphalt residue. A proposed method was carried out to reduce the negative impact on the bond between the aggregate and mortar by exposing the RAP aggregates to the pyrolysis process. The research focused on the analyses of the physical and chemical behavior of the aggregates, using the SEM, EDX, and FTIR approaches, as well as reviewing the mortar in both compressive and flexural tensile strength. The pyrolysis affected the physical and mechanical properties positively and the chemical composition of the RAP showed significant changes. The chemical constituents of asphalt attached to RAP aggregates are hydrocarbons. The thin layer of RAP asphalt is the cause of weak bonding, but this layer was altered by the pyrolysis procedure. As a result, water absorption decreased, which had a positive impact on the hydraulic synergy of cement. It is shown that the pyrolyzing RAP improves the compressive strength and flexural tensile strength through modification of the asphalt residue covering the aggregates.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The utilization of reclaimed asphalt pavement (RAP) aggregates as an alternative for rigid pavements is limited. The main objective of this study is to explore and improve the utilization of RAP aggregates as an alternative material for rigid pavement. Specifically, this study focuses on addressing a significant challenge associated with RAP aggregates, which is their poor bond with cementitious binders. The poor bonding results in low compressive and tensile strengths of concrete or mortar. The poor bonding is mainly due to the presence of a thin oily layer of asphalt residue. A proposed method was carried out to reduce the negative impact on the bond between the aggregate and mortar by exposing the RAP aggregates to the pyrolysis process. The research focused on the analyses of the physical and chemical behavior of the aggregates, using the SEM, EDX, and FTIR approaches, as well as reviewing the mortar in both compressive and flexural tensile strength. The pyrolysis affected the physical and mechanical properties positively and the chemical composition of the RAP showed significant changes. The chemical constituents of asphalt attached to RAP aggregates are hydrocarbons. The thin layer of RAP asphalt is the cause of weak bonding, but this layer was altered by the pyrolysis procedure. As a result, water absorption decreased, which had a positive impact on the hydraulic synergy of cement. It is shown that the pyrolyzing RAP improves the compressive strength and flexural tensile strength through modification of the asphalt residue covering the aggregates.
10.
Laurencius Nugrohoa; Yanuar Haryanto; Hsuan-Teh Hu; and Ay Lie Han; Fu-Pei Hsiao; Chia-Chen Lin; Pu-Wen Weng; Endah Purwaningsih Widiastuti
NSM-CFRP rods with varied embedment depths for strengthening RC T-beams in the negative moment region: Investigation on high cyclic response Journal Article
In: Composite Structures, vol. 331, 2024.
@article{nokey,
title = {NSM-CFRP rods with varied embedment depths for strengthening RC T-beams in the negative moment region: Investigation on high cyclic response},
author = {Laurencius Nugrohoa and Yanuar Haryanto and Hsuan-Teh Hu and and Ay Lie Han and Fu-Pei Hsiao and Chia-Chen Lin and Pu-Wen Weng and Endah Purwaningsih Widiastuti},
url = {https://www.sciencedirect.com/science/article/abs/pii/S0263822324000199},
doi = {10.1016/j.compstruct.2024.117891},
year = {2024},
date = {2024-01-06},
journal = {Composite Structures},
volume = {331},
abstract = {Throughout its service life, structural reinforced concrete (RC) encounters cyclic loads and the load amplitude might always vary, leading to a mixed high and low-cycle failure. This research investigates the high cyclic response of RC T-beams strengthened in the negative moment region using near-surface mounted (NSM) Carbon Fiber Reinforced Polymer (CFRP) rods. The distinctive aspect lies in exploring varied embedment depths, including the introduction of half-embedded configurations as an alternative NSM technique. The study comprehensively analyzes load-carrying capacity, failure modes, energy dissipation, ductility, stiffness degradation, and strain behavior, providing insights into the effects of loading rates on structural response. Through an experimental program comparing fully-embedded (BF-D) and half-embedded (BH-D) CFRP rods with a control beam (BN-D) under high-rate cyclic loading, significant increases in ultimate load capacity (21.23% for BH-D and 30.86% for BF-D) are demonstrated despite debonding occurrences. The findings highlight a trade-off between benefits (enhanced ultimate load capacities, improved energy dissipation, and increased stiffness) and drawbacks (reduced ductility and tendencies toward brittle behavior) under high loading rates. Furthermore, a rate-dependent material formula is developed and validated, predicting the flexural strength of the negative moment region in good agreement with experimental results. Finally, this research contributes practical solutions to RC element strengthening challenges and advances understanding of NSM-CFRP-strengthened beam, emphasizing the impact of loading rates on structural response.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Throughout its service life, structural reinforced concrete (RC) encounters cyclic loads and the load amplitude might always vary, leading to a mixed high and low-cycle failure. This research investigates the high cyclic response of RC T-beams strengthened in the negative moment region using near-surface mounted (NSM) Carbon Fiber Reinforced Polymer (CFRP) rods. The distinctive aspect lies in exploring varied embedment depths, including the introduction of half-embedded configurations as an alternative NSM technique. The study comprehensively analyzes load-carrying capacity, failure modes, energy dissipation, ductility, stiffness degradation, and strain behavior, providing insights into the effects of loading rates on structural response. Through an experimental program comparing fully-embedded (BF-D) and half-embedded (BH-D) CFRP rods with a control beam (BN-D) under high-rate cyclic loading, significant increases in ultimate load capacity (21.23% for BH-D and 30.86% for BF-D) are demonstrated despite debonding occurrences. The findings highlight a trade-off between benefits (enhanced ultimate load capacities, improved energy dissipation, and increased stiffness) and drawbacks (reduced ductility and tendencies toward brittle behavior) under high loading rates. Furthermore, a rate-dependent material formula is developed and validated, predicting the flexural strength of the negative moment region in good agreement with experimental results. Finally, this research contributes practical solutions to RC element strengthening challenges and advances understanding of NSM-CFRP-strengthened beam, emphasizing the impact of loading rates on structural response.