Characteristics of Palangkaraya fibrous peat Estu Yulianto, Faisal; Harwadi, Fuad; Rusdiansyahi
MATEC Web of Conferences,
2019, Volume:
276
Journal Article, Conference Proceeding
Peer reviewed
Open access
Palangkaraya fibrous peat soil is a soil with high organic content and was formed due to decomposition of plants in submerged areas for long periods. In the tropics, peat has a high fiber content ...that affects the physical and engineering characteristic and have different behavior with clay. Laboratory and field tests were conducted to determine the physical and engineering characteristic of fibrous peat and to compare it with clay. The results of the tests on fibrous peat show peat soil parameter very different from clays. The unit weight of peat is 1.04 gr/cm 3 with specific gravity is 1.4 and water content reach 650%. This physical parameter shows that peat is a very soft soil that is dominated by water in its structure. Organic content of peat reached 97% with a very low ash content of 3%. This behavior indicates that the decomposition of plants causes physical properties of peat that are very different from clays. The bearing capacity of the peat is also very low. The shear strength was about 26.8 kPa (ov = 50 kPa) and was dependent on the fiber distribution in the sample under test. Vane shear test results also show the same thing that is 5-7 kPa. The very different behavior of fibrous peat with clay is the consolidation. Peat has 4 stages of compression wherein secondary compression is the main compression. This behavior is due to the fibrous peat has two pores, that are micropores and macropores. The results of comparisons can serve as a basis for determining appropriate peat soil improvement methods.
Peat is a type of soil with high organic content, very low bearing capacity, and high uneven settlement. Some methods to improve soil have been applied to peat in order to make it strong enough for ...civilization-building foundation situated on it. Peat stabilization is a method that is continuously developed considering that the cost it needs is lower and this approach is more environmentally friendly compared to other methods. The admixture of lime (CaCO3) and Rice husk ash, a new ecofriendly stabilizer material, has been applied to peat soil and showed a good result. However, in studies conducted previously, the effect of water infiltration from surrounding areas of soil was stabilized was not involved as variable influencing the change of parameter. Based on that, this laboratory study was carried out to model the real condition in the field when the stabilization is performed and to identify the physical and engineering changes of peat soil in the 10th, 20th, and 30th days of stabilization in its border and middle parts, with the percentage of material stabilizer 5%, 10%, 15% and 20% of the unit weight of the initial condition of peat. The result of laboratory test shows that the addition of admixture of lime (CaCO3) and rice husk ash can improve the physical and engineering properties of peat soil are stabilized. Water infiltration occurred on peat soil is stabilized has not affected the physical and engineering properties of the soil. It can be seen from the physical and engineering properties of the border and central parts of peat soil is stabilized that still have a similar value. It is assumed to be caused by CaSiO3 gel formed still needs a longer duration to become stable gel. However, in this initial study it was known that the more stabilizers added, made the better the parameters of the stabilized peat soil.
This study aims to investigate conceptual understanding based on the cognitive process and to describe the learning obstacles faced by students to digest the notion of definition of a function. For ...this purpose, a case study is conducted by involving three undergraduate students of mathematics education program as the subjects. One is a second semester student (M1), and the other two are a sixth semester student (M2) and eighth semester student (M3), respectively. The data are collected using observation, tests, and interviews. We found that M1's process level of cognitive is in remembering. M1 experienced didactical, cognitive, and epistemological obstacles; M2's process level of cognition is in remembering and understanding, which reveals cognitive and epistemological obstacles; M3's process level of cognition is in remembering, which shows cognitive and epistemological obstacles. The results are definitely important to improve the process of teaching and learning at universities.This result is used as an evaluation material for students to be at the Analysis stage in terms of Bloom's taxonomy level. Thus, it will serve as a material for the lecturers to deliver the concept of function emphasizing on formal definition and representation.
Peat soil is formed through the accumulation of undecomposed plant organic matter, resulting in a high fiber content that leads to poor physical properties and low shear strength. Consequently, peat ...soil is identified as problematic and detrimental in infrastructure construction. One proposed method to improve its physical properties and enhance shear strength is biological soil stabilization through biotechnology, with bioaugmentation as an environmentally friendly alternative. The objective of this research is to accelerating the decomposition of peat fiber by
Pseudomonas taiwanensis
bacteria, thereby accelerating soil compaction and improving its physical properties and shear strength. The subject of this research is fibrous peat soil in Bereng Bengkel Village, Palangkaraya, Central Kalimantan. From the experimental results, it was found that the addition of 15%
Pseudomonas taiwanensis
bacteria to fibrous peat can significantly improve the physical properties and shear strength. Thus,
Pseudomonas taiwanensis
bacteria can be used as an environmentally friendly alternative to improve the geotechnical properties of fibrous peat.
Indonesia’s peatlands are concentrated in three major islands, namely Sumatra (35%), Kalimantan (32%), Papua (30%), and other islands (3%) of a total area of 21 million ha. Peat has a low carrying ...capacity. The carrying capacity of the soil is largely determined by the value of the water content contained in the peat. To overcome this problem, stabilization is carried out using a mixture of biopolymers to increase the carrying capacity of the soil. In this study, testing of the physical properties of peat soil was carried out in order to determine changes in the value of the physical properties of the soil that occurred after stabilization. The sampling location is in the area of Palangka Raya City. There were 5 variations of samples made for stabilizing peat soil with a mixture of 0.5%, 1%, 2%, 2.5%, and 3% biopolymer. The final results obtained after testing the physical properties of post-stabilization peat soil were a decrease in water content in the 3% biopolymer (395.13%) variation, the maximum decrease in fiber content in the 3% biopolymer (30.79%), and the maximum ash content obtained in the 3% biopolymer increasing the value of the bulk density at 3% bipolymer (1.64%), and increasing organic content (96.62%) at 3% biopolymer variation.
Abstrak Indonesia merupakan salah satu negara dengan sebaran lahan gambut yang luas. Gambut dikenal sebagai tanah yang bermasalah dalam pekerjaan konstruksi karena memiliki daya dukung yang rendah ...sehingga tidak dapat menopang pondasi infrastruktur. Tujuan penelitian ini adalah untuk menganalisis karakteristik tanah gambut di Kalimantan, sehingga penanganan yang tepat dapat ditentukan untuk mengatasi permasalahannya. Studi kasus pada penelitian ini adalah tanah gambut di Bereng Bengkel, Palangkaraya. Karakteristik tanah gambut diidentifikasi melalui serangkaian pengujian tanah berdasarkan Peat Testing Manual 1979. Selain itu, dilakukan juga pengujian Scanning Electron Microscopy untuk melihat morfologi tanah gambut, serta pengujian Fourier Transform Infra-Red untuk mengidentifikasi jenis senyawa yang terdapat di dalamnya. Hasil pengujian tanah di laboratorium menunjukkan bahwa tanah gambut memiliki sifat yang buruk secara geoteknik. Dari hasil pengujian SEM, diketahui adanya makropori dan mikropori pada tanah gambut yang sebagian besar ditempati oleh air. Kemudian, berdasarkan hasil pengujian FTIR, diketahui bahwa tanah gambut memiliki senyawa yang bersifat hidrofilik. Kata kunci: tanah gambut, serat gambut, infrastruktur Abstract Indonesia is one of the countries with a wide distribution of peatlands. Peat is known as a problematic soil in construction work because it has a low bearing capacity that cannot support infrastructure foundations. The objective of this research is to analyze the characteristics of peat soils in Kalimantan, so that appropriate treatments can be determined to overcome the problem. A case study of this research is the peat soil in Bereng Bengkel, Palangkaraya. The characteristics of the peat soil were identified through a series of soil tests based on the Peat Testing Manual 1979. In addition, Scanning Electron Microscopy testing was carried out to look at the morphology of the peat soil, as well as Fourier Transform Infra-Red testing to identify the types of compounds contained therein. The results of soil testing in the laboratory showed that the peat soil had poor geotechnical properties. SEM testing revealed macropores and micropores in the peat soil, most of which were occupied by water. FTIR testing showed that peat soil has hydrophilic compounds. Keywords: peat soil, peat fiber, infrastructure
Abstrak. Tanah gambut dikenal sebagai tanah yang sangat lunak dengan kandungan organik tinggi (≥75% ). Tanah gambut memiliki perilaku yang kurang menguntungkan, yaitu daya dukung yang rendah dan ...pemampatan yang besar. Metode perbaikan tanah, seperti: preloading dengan beban tambahan, kolom pasir, dan galar kayu telah dilakukan untuk meningkatkan perilakunya. Hanya saja, metode tersebut tidak ramah lingkungan karena menggunakan banyak tanah dan kayu. Karena itu, metode stabilisasi menggunakan kapur telah dikembangkan untuk meningkatkan perilaku gambut. Makalah ini menyajikan efektivitas penggunaan abu sekam padi (RHA) dan Fly Ash (FA) sebagai pozolon untuk dicampurkan dengan CaCO3 sebagai bahan stabilisasi dan pengaruh Usia stabilisasi terhadap perilaku tanah gambut yang distabilisasi. Dalam studi ini, digunakan 10 % Admixture-1 (30% CaCO3 +70% RHA) dan 10% Admixture-2 (30% CaCO3 +70 % FA). Pada usia stabilisasi 20-45 hari, perilaku tanah gambut yang distabilisasi meningkat secara signifikan. Pada usia peram diatas 45 hari perilaku gambut yang distabilisasi menurun karena adanya perubahan jelly CaSiO3 menjadi kristal dan terjadinya dekomposisi serat gambut. Meskipun dua jenis admixture tersebut memberikan hasil yang baik dalam meningkatkan perilaku gambut berserat, tetapi Admixture-2 menunjukkan hasil yang lebih menjanjikan karena ukuran butirannya yang lebih halus dan kemudahannya dalam pelaksanaan pencampuran. Abstract. Peat soil is known as a very soft soil with high organic content (≥ 75%). It has unfavorable behaviour, that is, low bearing capacity and very high compressibility. Soil improvement methods, such as: preloading with surcharge, sand column, and corduroy have been adopted to improve its behaviour. Those methods, however, are not environmentally friendly because they use a lot of irreversible materials. Because of that, stabilization method using lime had been developed to improve peat behaviour. This paper presents the effectiveness of using rice husk ash (RHA) and Fly Ash (FA) as pozolon to enhance the CaCO3 for stabilization material and the effect of curing period to the behavior of stabilized peat soil. In this study, 10% of Admixture-1 (30% CaCO3+70% RHA) and 10% of Admixture-2(30% CaCO3+70% FA) were used. During 20-45 days curing period, very significant improvement of the stabilized peat soil behaviour occured. After that, however, slightly decreament of the stabilized peat behaviour happened caused by the change of CaSiO3gel to be crystal and by the fibers peat decomposition. Although both types of admixtures gave good results in improving the stabilized fibrous peat behaviour, however, Admixture-2 gives more promising results due to its finergrain size and easier in mixing.
Sebelum membangun di atas tanah gambut harus dilakukan perlakuan treatment khusus agar struktur yang dibangun dapat stabil. Salah satu metode yang telah diusulkan untuk memperbaiki sifat tanah gambut ...adalah stabilisasi tanah biologis melalui pendekatan bioteknologi. Metode bioaugmentasi merupakan salah satu pendekatan perbaikan tanah yang ramah lingkungan. Penelitian ini bertujuan untuk mempercepat dekomposisi serat gambut, menurunkan kadar air dan mengatasi tingkat keasaman yang tinggi pada tanah gambut. Dalam studi eksperimen ini, bakteri pseudomonas taiwanensis digunakan sebagai agen dalam proses bioaugmentasi, karena memiliki kemampuan yang tinggi dalam dekomposisi serat gambut. Hasil penelitian menunjukkan bahwa penambahan bakteri pseudomonas taiwanensis sebesar 5% di masa pemeraman 28 hari berhasil mengurangi kadar air hingga 309,45%, dari awalnya 704,02% menjadi 394,57%. Selain itu, terjadi peningkatan signifikan pada nilai pH, dari 3,2 menjadi 6,5, pada semua variasi sampel. Oleh karena itu, dapat disimpulkan bahwa bakteri pseudomonas taiwanensis dapat efektif meningkatkan sifat fisik tanah gambut.
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