Hartono, Juandra (2026) Perilaku Mekanik dan Durabilitas Struktur Beton Menggunakan HVFA-SCC di Lingkungan Pesisir. Doctoral thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Kondisi lingkungan pesisir yang agresif mempercepat degradasi struktural bangunan marin, terutama akibat siklus basah-kering ekstrem pada zona pasang surut. Tingkat porositas yang tinggi pada beton konvensional menyebabkan struktur menjadi kurang kedap, sehingga penetrasi unsur korosif terjadi lebih cepat dan umur layan rencana bangunan tidak dapat tercapai. Meskipun aplikasi High Volume Fly Ash Self-Compacting Concrete (HVFA-SCC) terus dieksplorasi, tantangan teknis dalam menjaga stabilitas performa pada tingkat substitusi fly ash (FA) yang tinggi (>60%) masih menjadi perhatian utama. Selain itu, keterbatasan data empiris mengenai perilaku elemen struktur beton di zona pasang surut nyata masih menjadi hambatan, mengingat mayoritas riset durabilitas selama ini lebih banyak bertumpu pada metode simulasi percepatan di laboratorium. Eksplorasi komprehensif terhadap perilaku mekanik dan durabilitas beton HVFA-SCC dilakukan melalui studi integratif dan validasi in situ selama 365 hari. Studi ini menggunakan variabel substitusi FA sebesar 60% dan 70% serta bottom ash (BA) sebesar 20%, yang diaktivasi menggunakan formulasi hybrid (aktivator alkali dan bahan kapur) untuk menjamin stabilitas kemampuan alir dan durabilitas beton. Pengujian melibatkan balok struktur bertulang dan non-bertulang yang ditempatkan di zona pasang surut Jembatan Suramadu dan Pantai Marina Semarang, di mana data eksperimen lapangan digunakan untuk memvalidasi simulasi perilaku struktur menggunakan DIANA FEA 10.5 Hasil penelitian menunjukkan bahwa setelah paparan 365 hari, balok HVFA-SCC-60 mencapai integritas struktural tertinggi dengan kapasitas beban puncak mencapai 133,38 kN dan momen ultimit sebesar 30,92 kNm, atau meningkat 9,6% dari campuran kontrol. Performa jangka panjang ini didukung oleh kualitas material awal, dengan interfacial bond strength 2,80 MPa pada umur 28 hari, serta kuat tekan jangka panjang 64,25 MPa yang secara sinergis menjaga kekakuan penampang. Densifikasi mikrostruktur menggeser mekanisme kegagalan dari retak lebar tunggal menjadi distribusi retak rambut yang rapat, sekaligus mengoptimalkan ketangguhan lentur hingga 740,86 J. Reduksi porositas terbuka sebesar 36,9% secara signifikan menghambat difusi klorida, ekspansi sulfat, dan kedalaman karbonasi. Validasi numerik yang dilakukan mengonfirmasi akurasi model dengan deviasi beban di bawah 2,6%, sehingga optimasi kadar FA 60% dipastikan mampu menjamin reliabilitas mekanis dan resiliensi durabilitas yang optimal bagi infrastruktur di lingkungan pesisir yang agresif.
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Aggressive coastal environments accelerate the structural degradation of marine infrastructure, primarily due to extreme wetting-drying cycles in the tidal zone. High porosity in conventional concrete reduces structural impermeability, facilitating the rapid penetration of corrosive agents and preventing structures from achieving their design service life. Although researchers continue to explore the application of High Volume Fly Ash Self-Compacting Concrete (HVFA-SCC), maintaining performance stability at high fly ash (FA) substitution levels (>60%) remains a primary concern. Furthermore, limited empirical data on the behavior of concrete structural elements in real-world tidal zones hinders current progress, as most durability research relies on accelerated laboratory testing methods. This study comprehensively explores the mechanical behavior and durability of HVFA-SCC through an integrative study and in situ validation over 365 days. The research employs FA substitution levels of 60% and 70%, combined with 20% bottom ash (BA), activated using a hybrid formulation (alkali activator and calcareous materials) to ensure stability in workability and durability. The testing involved reinforced and non-reinforced structural beams placed in the tidal zones of the Suramadu Bridge and Marina Beach in Semarang, where the field experimental data were used to validate the structural behavior simulations performed using DIANA FEA 10.5 Results indicate that after 365 days of exposure, the HVFA-SCC-60 beams achieved the highest structural integrity, with a peak load capacity of 133.38 kN and an ultimate moment of 30.92 kNm, representing a 9.6% increase over the control mixture. This long-term performance was supported by the initial material quality, featuring an interfacial bond strength of 2.80 MPa at 28 days, along with a long-term compressive strength of 64.25 MPa, which synergistically maintained cross-sectional stiffness. Microstructural densification shifted the failure mechanism from a single wide crack to a dense distribution of fine cracks, while optimising flexural toughness to 740.86 J. A 36.9% reduction in open porosity significantly inhibited chloride diffusion, sulfate expansion, and carbonation depth. Numerical validation confirmed the model's accuracy, with a load deviation of less than 2.6%, ensuring that the optimised 60% FA content effectively guarantees the mechanical reliability and durability of infrastructure in aggressive coastal environments.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Uncontrolled Keywords: | HVFA-SCC, Fly Ash, Structural Behavior, Durability, Tidal Zone, Perilaku Struktural, Durabilitas, Zona Pasang Surut |
| Subjects: | T Technology > TA Engineering (General). Civil engineering (General) > TA440 Concrete--Cracking. T Technology > TA Engineering (General). Civil engineering (General) > TA444 Reinforced concrete |
| Divisions: | Faculty of Civil Engineering and Planning > Civil Engineering > 22001-(S3) PhD Thesis |
| Depositing User: | Juandra Hartono |
| Date Deposited: | 24 Jul 2026 22:18 |
| Last Modified: | 24 Jul 2026 22:18 |
| URI: | http://repository.its.ac.id/id/eprint/137334 |
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