Pengaruh Bakteri Bacillus megaterium sebagai Self-Healing Agent terhadap Kuat Lentur dan Kuat Tarik Tidak Langsung Beton Geopolimer

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ABSTRAK

Beton geopolimer disusun dari material daur ulang yang ramah lingkungan, yaitu fly ash, recycled concrete aggregate, serta limbah serbuk cangkang telur dan kerang, sebagai upaya pengurangan penggunaan semen portland. Metode penelitian dilakukan melalui pengembangbiakan bakteri, pengolahan agregat limbah, pengujian sifat fisis material, serta pembuatan benda uji silinder dan balok. Hasil pengujian menunjukkan beton normal memiliki kuat tarik tidak langsung dan kuat lentur lebih tinggi dibandingkan dengan beton geopolimer. Penambahan bakteri mampu meningkatkan kekuatan beton geopolimer secara signifikan. Nilai kuat lentur beton geopolimer berbasis self-healing meningkat sekitar 29% dibandingkan dengan geopolimer biasa dan mendekati performa beton normal. Namun, beton geopolimer tidak mengalami self-healing disebabkan oleh larutan aktivator alkali 10 M dengan pH > 14. Meskipun kekuatan tekan mungkin melebihi beton geopolimer biasa, lingkungan alkali yang kuat bukanlah pH yang sesuai untuk bakteri Bacillus megaterium.

Kata kunci: Bacillus megaterium, beton geopolimer, kuat lentur, kuat tarik tidak langsung, self-healing 

ABSTRACK

Geopolymer concrete is composed of environmentally friendly recycled materials, namely fly ash, recycled concrete aggregate, as well as waste powder from eggshells and seashells, as an effort to reduce the use of Portland cement. The research method was carried out through bacterial cultivation, waste aggregate processing, testing of the physical properties of materials, and the fabrication of cylindrical and beam specimens. The test results showed that normal concrete had higher splitting tensile strength and flexural strength compared to geopolymer concrete. The addition of bacteria was able to significantly improve the strength of geopolymer concrete. The flexural strength of self-healing-based geopolymer concrete increased by about 29% compared to ordinary geopolymer and approached the performance of normal concrete. However, geopolymer concrete did not undergo self-healing due to the use of a 10M alkaline activator solution with a pH > 14. Although the compressive strength may exceed that of ordinary geopolymer concrete, the strong alkaline environment is not a suitable pH for Bacillus Megaterium bacteria

Keywords: Bacillus megaterium, geopolymer concrete, flexural strength, indirect tensile strength, self-healing