Pengaruh Bakteri Bacillus Megaterium sebagai Self-Healing Agent pada Kuat Tekan Beton Mutu Tinggi

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ABSTRAK

Sifat beton yang lemah terhadap tarik memungkinkan terjadinya retakan mikro dan dapat merambat menjadi retakan makro, apabila retakan tersebut tidak terdeteksi. Oleh karena itu, muncul inovasi yang disebut dengan Self-healing concrete (SHC), yaitu beton dapat menutupi retakan mikro secara mandiri tanpa adanya perlakuan dari manusia. Pada penelitian ini, digunakan bakteri Bacillus megaterium sebagai healing agent kemudian diterapkan pada beton mutu tinggi rencana 45 MPa berdasarkan pedoman ACI 211-4r.93, dengan kadar subtitusi semen oleh fly ash sebanyak 25% dan persentase bakteri sebesar 2% dari komposisi air yang digunakan. Hasilnya, diperoleh peningkatan nilai kuat tekan pada beton bakteri umur 28 hari sebesar 12,662% terhadap beton kontrol. Dimana nilai kuat tekan rata-rata 62,199 MPa pada beton bakteri dan 55,208 MPa untuk beton kontrol. Selain itu, beton bakteri mulai menunjukkan proses self-healing pada hari ke-21 pasca pengujian dan lebar ukuran retakan mikro yang dapat diperbaiki bakteri adalah berkisar 0,66-2,76 mm.

Kata kunci: beton mutu tinggi, self-healing concrete, bacillus megaterium, kuat tekan

ABSTRACT

The weak tensile properties of concrete allow micro-cracks to occur and propagate into macro-cracks if they are not detected. Therefore, an innovation called Self-healing concrete (SHC) emerged, where concrete can cover micro-cracks independently without human treatment. In this study, Bacillus megaterium bacteria were used as a healing agent. Then they applied to high-strength concrete plan 45 MPa based on ACI guideline 211-4r.93, with a cement substitution content by fly ash of 25% and a percentage of bacteria of 2% of the composition of the water used. As a result, an increase in compressive strength value was obtained in bacterial concrete aged 28 days by 12.662% against control concrete. Where bacterial concrete was 7,524 MPa and control concrete was 7,399 MPa. In addition, bacterial concrete began to show a self-healing process on the 21st day after the compressive test, and the width of the size of micro-cracks that bacteria can repair is in the range of 0.66-2.76 mm.

Keywords: high strength concrete, self-healing concrete, bacillus megaterium, compressive strength