Electronic Theses and Dissertation

Kerusakan pada struktur beton akibat beban impact menjadi salah satu permasalahan yang dapat menurunkan kapasitas dan umur layan struktur. oleh karena itu, diperlukan metode perbaikan yang efektif dan berkelanjutan, salah satunya melalui teknologi self-healing concrete berbasis bakteri. penelitian ini bertujuan untuk menganalisis pengaruh penggunaan bakteri bacillus sp. sebagai agen self-healing concrete melalui metode injeksi terhadap perilaku pelat beton bertulang mutu tinggi 85 mpa yang mengalami gagal impact. penelitian dilakukan pada pelat beton bertulang dengan tiga variasi dimensi, yaitu 40×40×4 cm, 60×60×6 cm, dan 80×80×8 cm. bakteri bacillus sp. digunakan dengan konsentrasi 0,6% dari berat semen yang dikombinasikan dengan urea 0,53%, cacl₂ 0,27%, dan nutrient broth 0,13%. metode penelitian dilakukan dengan memberikan beban impact awal sebesar 70% dari beban ultimit untuk menghasilkan retak awal, kemudian retakan diperbaiki menggunakan metode injeksi suspensi bakteri dan dilakukan perawatan perendaman selama 28 hari sebelum diuji kembali hingga runtuh. parameter yang diamati meliputi jumlah pukulan, energi serapan, kedalaman benturan, pola retak, serta hubungan pukulan-regangan pada beton dan tulangan baja. hasil penelitian menunjukkan bahwa penggunaan bakteri bacillus sp. mampu memperbaiki retakan akibat impact melalui proses presipitasi kalsium karbonat (caco₃) sehingga meningkatkan kembali kapasitas pelat beton setelah injeksi. beton mutu tinggi yang digunakan memiliki kuat tekan rata-rata sebesar 88,17 mpa. pada benda uji kontrol tanpa injeksi p8-n keruntuhan terjadi pada 1003 pukulan dengan energi serapan 29.518,29 j dan kedalaman benturan 2,4 cm. setelah dilakukan injeksi bakteri p8-i keruntuhan terjadi pada 1239 pukulan dengan energi serapan 36.463,77 j dan kedalaman benturan 2,3 cm. dengan demikian, metode injeksi menggunakan bakteri bacillus sp. terbukti efektif sebagai teknologi perbaikan mandiri (self-healing) pada beton mutu tinggi yang mengalami kerusakan akibat beban impact.

Damage to concrete structures caused by impact loading is one of the major problems that can reduce the load-carrying capacity and service life of structures. Therefore, an effective and sustainable repair method is required, one of which is bacterial-based self-healing concrete technology. This study aims to analyze the effect of Bacillus sp. bacteria as a self-healing agent applied through the injection method on the behavior of high-strength reinforced concrete slabs with a compressive strength of 85 MPa that had experienced impact failure. The study was conducted on reinforced concrete slabs with three different dimensions: 40 × 40 × 4 cm, 60 × 60 × 6 cm, and 80 × 80 × 8 cm. Bacillus sp. bacteria were used at a concentration of 0.6% by weight of cement, combined with 0.53% urea, 0.27% CaCl₂, and 0.13% Nutrient Broth. The experimental procedure involved applying an initial impact load equal to 70% of the ultimate impact capacity to induce initial cracking. The cracks were then repaired by injecting a bacterial suspension, followed by water curing for 28 days before the specimens were retested under repeated impact loading until failure. The observed parameters included the number of impact blows, absorbed impact energy, impact crater depth, crack pattern, and the relationship between the number of blows and strain in both concrete and reinforcing steel. The results showed that the use of Bacillus sp. effectively repaired impact-induced cracks through the precipitation of calcium carbonate (CaCO₃), thereby restoring and improving the impact resistance of the reinforced concrete slabs after injection. The high-strength concrete achieved an average compressive strength of 88.17 MPa. In the control specimen without bacterial injection (P8-N), failure occurred after 1,003 blows with an absorbed impact energy of 29,518.29 J and an impact crater depth of 2.4 cm. After bacterial injection (P8-I), failure occurred after 1,239 blows with an absorbed impact energy of 36,463.77 J and an impact crater depth of 2.3 cm. These findings demonstrate that the bacterial injection method using Bacillus sp. is an effective self-healing repair technology for restoring the impact performance of high-strength concrete subjected to impact-induced damage.