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STRUKTURMIKRO DAN SIFAT FISIK-MEKANIK BETON RINGAN TANPA PEMATANGAN DALAM AUTOCLAVE (NON AUTOCLAVED AERATED CONCRETE, NAAC) Sri Harjanto; Prima Sony; Bambang Suharno; Henki W. Ashadi
Jurnal Sains Materi Indonesia Vol 9, No 2: FEBRUARI 2008
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1315.047 KB) | DOI: 10.17146/jsmi.2008.9.2.4746

Abstract

STRUKTURMIKRO DAN SIFAT FISIK-MEKANIK BETON RINGAN TANPA PEMATANGAN DALAM AUTOCLAVE (NON AUTOCLAVED AERATED CONCRETE, NAAC). Pembuatan beton ringan umumnya menekankan pada dua hal, yaitu massa jenis yang serendah mungkin dan kuat tekan yang setinggi-tingginya. Penelitian ini mengamati strukturmakro dan stukturmikro, sifat fisika-mekanika dan keterkaitannya satu sama lain. Dalam penelitian ini, beton ringan dibuat tanpa pematangan dalam autoclave (Non Autoclaved Aerated Concrete, NAAC) dengan penambahan senyawa pengaerasi Al (2 % massa) dan H2O2 (32 % massa) secara terpisah. Alkalinitas campuran beton ringan ini dikontrol dengan penambahan kapur sampai jumlah tertentu. Diperoleh hasil massa jenis beton ringan NAAC dengan senyawa pengaerasi Al dan H2O2 masing-masing adalah 1126 kg/m3 dan 1163 kg/m3. Sedangkan kuat tekan yang dihasilkan dari beton ringan dengan senyawa pengaerasi Al dan H2O2 masing-masing adalah 2,74 MPa dan 3,48 MPa. Massa jenis beton ringan NAAC masih lebih tinggi, sedangkan kuat tekannya relatif lebih rendah dibanding beton ringan dengan pematangan dalam autoclave (Autoclaved Aerated Concrete, AAC). Hasil penelitian ini juga mengindikasikan pengaruh pori terhadap massa jenis dan fasa strukturmikro dengan kuat tekan.
The Effects of Corrosive Chemicals on Corrosion Rate of Steel Reinforcement Bars: I. Swamp Water Widanarko, Sulistyoweni; Ashadi, Henki W.; Wicaksono, Andri Krisnadi
Makara Journal of Technology Vol. 6, No. 2
Publisher : UI Scholars Hub

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Abstract

Most of infrastructures using steel concrete to reinforce the strength of concrete. Steel concrete is so vulnerable to chemical compounds that can cause corrosion. It can happen due to the presence of chemical compounds in acid environment in low pH level. These chemical compounds are SO4 2-, Cl-, NO3 -. There are many swamp area in Indonesia. The acid contents and the concentration of ion sulphate, chlorides, and nitrate are higher in the swamp water than in the ground water .The objective of this research was to find out the influence of corrosive chemicals in the swamp water to the steel concrete corrosion rate. There were two treatment used: (1) emerging ST 37 and ST 60 within 60 days in the ‘polluted’ swamp water, (2) moving the ST 37 up and down periodically in the ‘ polluted’ swamp water. Three variation of ’polluted’ swamp water were made by increasing the concentration of corrosive chemical up to 1X, 5X and 10X respectively. The corrosion rate was measured by using an Immersion Method. The result of Immersion test showed that chloride had the greatest influence to corrosion rate of ST 37 and ST 60 and followed by sulphate and Nitrate. Corrosion rate value for ST 37 is 24.29 mpy and for ST 60 is 22.76 mpy. By moving the sample up and down, the corrosion rate of ST 37 increase up to 37.59 mpy, and chloride still having the greatest influence, followed by sulphate and nitrate.
A STATE-OF-THE-ART REVIEW OF COLD-FORMED BUILT-UP BEAM SECTIONS Swastika, Tri Widya; Purnomo, Heru; Ashadi, Henki Wibowo; Soekarno, Praganif
Applied Research on Civil Engineering and Environment (ARCEE) Vol. 6 No. 01 (2025): Material Technology and Digitalization
Publisher : POLITEKNIK NEGERI JAKARTA

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32722/arcee.v6i01.7388

Abstract

Cold-formed steel (CFS) built-up beam sections have attracted significant attention in structural engineering due to their high strength-to-weight ratio, ease of fabrication, and cost efficiency. The most valuable is to specifically address the issue of torsional rigidity that occasionally occurs in single symmetrical or open sections. Utilizing screws, bolts, or spot welding as intermediate fasteners throughout the length of the member is crucial for connecting two single sections into a box section. This helps prevent the single sections from buckling independently by providing an intermediate fastener (a tie constraint at the screw). This paper presents a state-of-the-art review of cold-formed built-up beam sections, focusing on their structural behavior, design methodologies, and recent advancements. Various built-up configurations, including face-to-face, back-to-back, and boxed sections, are examined in terms of moment capacity, buckling modes, and failure mechanisms. A comprehensive analysis of experimental, numerical, and analytical studies is provided, highlighting key parameters affecting the performance of built-up beams, such as sectional geometry, flexural loading types, intermediate fastener types, screw spacing, built-up section types, and failure mode, encompassing 18 academic publications from 2009 to 2024, identifying gaps in existing design provisions for built-up sections. Future research directions are proposed, emphasizing the need for further investigations of cold-formed built-up beam sections. This review is a helpful resource for students, researchers, engineers, and industry professionals seeking to enhance the understanding and use of cold-formed built-up beam sections in modern construction.