Electronic Theses and Dissertation

Abstrak

Beton mutu tinggi membutuhkan jumlah semen lebih banyak daripada beton konvensional. Oleh karena itu digunakan tanah diatomae untuk mengurangi pemakaian semen, hal ini karena reaksi antara semen dan air menghasilkan panas hidrasi dan juga perbedaan kelembaban antara beton dan lingkungan sekitarnya yang menyebabkan terjadinya regangan susut lalu menyebabkan perambatan retak. Serat alam digunakan untuk menahan formasi retakan akibat regangan susut. Serat rami dipilih karena bersifat ekonomis, ramah lingkungan, dan biaya produksi yang rendah. Berdasarkan kondisi tersebut, tujuan penelitian ini adalah mengetahui pengaruh variasi penambahan serat rami terhadap susut beton mutu tinggi dengan penggunaan tanah diatomae sebagai substitusi semen. Benda uji yang digunakan berbentuk balok dengan ukuran 100 mm × 100 mm × 400 mm, pengamatan susut dilakukan selama 60 hari. Digunakan serat rami dengan variasi 0%, 0,15%, 0,30%, dan 0,45% dari volume beton. Dalam penelitian ini digunakan substitusi tanah diatomae dengan substitusi 0% dan 10% dari berat semen serta digunakan FAS 0,3. Benda uji berjumlah 32 benda uji. Hasil penelitian ini menunjukkan bahwa variasi penambahan serat rami ke dalam campuran beton berpengaruh terhadap pengurangan penyusutan. Pada umur 60 hari, jika dibandingkan dengan benda uji 0% serat rami penambahan serat rami sebesar 0,15%, 0,30%, 0,45% menunjukkan penurunan susut sebanyak 14%, 22%, dan 35% pada benda uji dengan substitusi 0% tanah diatomae, hal yang sama juga terjadi pada benda uji dengan substitusi 10% tanah diatomae yang mengalami penurunan sebanyak 19%, 24%, dan 32% untuk masing-masing variasi penambahan serat rami. Dari hasil pengamatan nilai regangan susut yang terjadi pada benda uji dengan substitusi 0% tanah diatomae lebih besar daripada benda uji dengan substitusi 10% tanah diatomae.

Kata Kunci: beton mutu tinggi, serat rami, tanah diatomae, susut

Abstract High strength concrete requires more cement than conventional concrete. Therefore, diatomaceous earth is used to reduce the use of cement, this is because the reaction between cement and water produces heat of hydration and also the difference in humidity between the concrete and the surrounding environment causes shrinkage strain and then causes crack propagation. Natural fibers are used to resist crack formation due to shrinkage strain. Ramie fiber was chosen because it is economical, environmentally friendly, and low production cost. Based on these conditions, the purpose of this study was to determine the effect of variations in the addition of ramie fiber on the shrinkage of high quality concrete with the use of diatomaceous earth as a substitute for cement. The test specimens used were in the form of beams with a size of 100 mm × 100 mm × 400 mm, the observation of shrinkage was carried out for 60 days. Ramie fiber was used with variations of 0%, 0.15%, 0.30%, and 0.45% of the concrete volume. In this study, diatomaceous earth substitution was used with 0% and 10% substitution by weight of cement and FAS 0.3 was used. The test specimens totaled 32 specimens. The results of this study indicate that the variation of ramie fiber addition to the concrete mix affects the reduction of shrinkage. At the age of 60 days, when compared to the 0% ramie fiber test specimen, the addition of ramie fiber of 0.15%, 0.30%, 0.45% showed a decrease in shrinkage of 14%, 22%, and 35% in the test specimen with 0% substitution of diatomaceous earth, the same thing also happened to the test specimen with 10% substitution of diatomaceous earth which decreased by 19%, 24%, and 32% for each variation of ramie fiber addition. From the observation of the shrinkage strain value that occurs in the test specimen with 0% substitution of diatomaceous earth is greater than the test specimen with 10% substitution of diatomaceous earth. Keyword: high performance concrete, ramie fiber, diatomaceous earth, shrinkage