Electronic Theses and Dissertation

Infrastruktur beton mutu tinggi di kawasan pesisir sangat rentan mengalami degradasi struktural akibat penetrasi agresif ion sulfat dan klorida yang diakselerasi oleh siklus basah-kering. untuk mengatasi permasalahan tersebut, penelitian ini bertujuan menganalisis pengaruh penambahan bakteri bacillus sp. dengan variasi konsentrasi 0,5% dan 0,7% terhadap berat semen dalam meningkatkan kemampuan penyembuhan retak, kuat tekan, serta durabilitas beton mutu tinggi 70 mpa. metodologi pengujian diawali dengan pembuatan 30 sampel benda uji kubus berdimensi 10×10×10 cm3. setelah proses hidrasi awal, seluruh benda uji dirawat dalam air tawar selama 28 hari, kemudian diberi pembebanan sebesar 60% dari kapasitas ultimit diumur 28 hari untuk menginduksi retak awal. selanjutnya benda uji diinjeksi larutan bakteri dengan kadar 0,5% dan 0,7%, setelah itu direndam kembali masing-masing 12 benda uji dengan kadar bakteri 0%, 0,5% dan 0,7% dalam larutan mgso4 dan nacl selama 90 hari, setelah perendaman selesai dilakukan pengujian kuat tekan ultimit pada semua benda uji. hasil pengujian menunjukkan bahwa pada rendaman nacl dengan variasi konsentrasi bakteri 0,7% menghasilkan tekanan kuat ultimit dan durabilitas tertinggi mencapai 70,94 mpa dengan efisiensi penutupan celah retak sebesar 80,40%. sementara itu, pada media rendaman mgso4 dengan variasi bakteri 0,7% tetap mampu memitigasi degradasi dengan mempertahankan kuat tekan pada angka 65,54 mpa dan menunjukkan intensitas penyembuhan retak sebesar 23,36%. berdasarkan perbandingan data tersebut, dapat disimpulkan bahwa aktivitas biomineralisasi bakteri bacillus sp. bekerja jauh lebih optimal di lingkungan dengan perendaman menggunakan nacl dibandingkan dengan mgso4. dengan demikian, inovasi teknologi self-healing concrete ini berpotensi memberikan kontribusi signifikan dalam pengembangan material konstruksi laut yang berkelanjutan dan berdaya layan panjang.

High-quality concrete infrastructure in coastal areas is highly susceptible to structural degradation due to the aggressive penetration of sulfate and chloride ions, which is accelerated by wet-dry cycles. To address this issue, this study aims to analyze the effect of adding Bacillus sp. bacteria at concentrations of 0.5% and 0.7% by weight of cement on the crack-healing ability, compressive strength, and durability of high-strength 70 MPa concrete. The testing methodology began with the preparation of 30 cubic test specimens measuring 10×10×10 cm³. After the initial hydration process, all test specimens were cured in fresh water for 28 days, then loaded to 60% of their ultimate capacity at 28 days to induce initial cracking. Next, the test specimens were injected with a bacterial solution at concentrations of 0.5% and 0.7%; thereafter, 12 test specimens each with bacterial concentrations of 0%, 0.5%, and 0.7% were re-immersed in a solution of MgSO₄ and NaCl for 90 days. After the immersion period, ultimate compressive strength testing was conducted on all test specimens. Test results showed that in the NaCl curing solution with a bacterial concentration of 0.7%, the highest ultimate compressive strength and durability were achieved, reaching 70.94 MPa with a crack closure efficiency of 80.40%. Meanwhile, in MgSO₄ immersion media with a bacterial concentration of 0.7%, the bacteria were still able to mitigate degradation by maintaining compressive strength at 65.54 MPa and demonstrating a crack healing intensity of 23.36%. Based on a comparison of these data, it can be concluded that the biomineralization activity of Bacillus sp. bacteria functions far more optimally in an environment with NaCl immersion compared to MgSO₄. Thus, this self-healing concrete technology innovation has the potential to make a significant contribution to the development of sustainable and long-lasting marine construction materials.