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"Material merupakan salah satu elemen terpenting dalam dunia konstruksi. khususnya untuk dunia konstruksi beton. Kerusakan yang terjadi pada struktur beton dapat disebabkan oleh banyak hal, secara umum faktor penyebab kerusakan dapat digolongkan menjadi tiga, yaitu: pengaruh fisika, mekanika, dan kimia. Kerusakan beton akibat pengaruh kimia merupakan hal yang sangat sulit untuk diperbaiki dan dihindari. Contoh kerusakan akibat pengaruh kimia adalah korosi beton akibat air laut dan akibat limbah dari pabrik. Oleh karena itu dibutuhkan metode dan material baru dalam mengantisipasi kerusakan beton akibat pengaruh kimia tersebut. Salah satu metode yang dalam mengantisipasi pengaruh kimia tersebut adalah dengan melindungi permukaan beton (protective coating). Material yang dianggap mampu melindungi permukaan beton dari pengaruh kimia khususnya zat asam adalah geopolimer. Geopolimer terdiri dari bahan prekursor dan aktivator yang melalui proses polimerisasi. Material geopolimer dalam penelitian ini menggunakan bahan dasar kaolin. Penelitian ini dilakukan untuk menganalisis kekuatan geopolimer sebagai lapisan pelindung beton dan pengaruhnya terhadap kekuatan beton. Metode yang digunakan adalah metode konvensional yaitu pencetakan. Parameter yang akan diteliti adalah kuat tekan, permeabilitas dan ketahanan asam material beton dengan geopolimer sebagai lapisan pelindungnya. Hasil penelitian ini diharapkan dapat memberikan gambaran kekuatan beton terhadap bahan perusak yaitu asam, dan pengaruhnya jika diberi lapisan pelindung dengan material geopolimer.

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Material is one of the important elements in the world of construction, especially in concrete construction. The fail of concrete structure is can be determined by a lots of factor, the fail of concrete structures can be determined into three factors, that is physics, mechanics and chemical. The fail of concrete structure because of chemical influences is the hardest way to ignore or to fix it. For example the fail of concrete structure because of chemical influences is concrete corrosion or abrasion because of sea water and raw waste from the industry. That is way we need a new method and new material to anticipate the failing of concrete structures. One of the method to anticipate the acid attack is protective coatings. The material that assumed can covering the surface of the concrete from acid attack is geopolymer. Geopolymer is consists of precursor and activator through polymeritation. Geopolymer material base used in this research are caoline. The goal of this research is to analyse the strength of geopolymer as protective coatings of the concrete and the influences for its compressive strength. The method we use is conventional method that is moulding. Parameters to be research are compressive strength and acid resistance ability of geopolymer as protective coatings. Hopefully this research we shall know and describe the concrete strength of acid resistance ability and the influences of giving geopolymer as protective coating for the concrete."

"The addition of alumina and wollastonite in geopolymer resin is expected to increase the thermal behavior of the geopolymer matrix composite. In this work, fine granules of solid alumina and acicular wollastonite used as filler were mixed with a fly ash-based geopolymer resin paste to form a composite matrix. The filler additions were 2.5% to 10.0% of the total weight with sodium silicates and sodium hydroxide used as activators. The results showed that the addition of alumina and wollastonite as filler did not have much effect on the flexural and compressive strength of the geopolymer matrix composite at room temperature. Wollastonite fiber, which was added in the form of a short-sized fiber, only produced a very small bridging effect. Nevertheless, alumina filler composite showed a good result after being exposed to a temperature at 200°C, although the strength was reduced as the temperature increased. Moreover, wollastonite fibers only managed to maintain 50% of their flexural strength after 2 hours exposure at a temperature of 200°C due to the damage of the wollastonite fiber."

"Pada masa ini penelitian mengenai busa poliuretan dipusatkan pada usaha peningkatan karakteristik kekakuan busa dengan pemilihan bahan baku dan proses yang bersifatterbarukan. Bio-coating kitosan adalah polisakarida linear yang merupakan produk turunan dari chitin, yaitu zat penyusun rangka terluar dari hewan antropoda sepertiudang, kepiting, dan serangga. Hubung silang antara busa poliuretan dengan kitosan dibuktikan dari hasil pengamatan SEM dimana terbentuknya lapisan pada permukan dan pori pori busa. Kemudian pengujian FTIR yang menunjukkan fenomena curing terjadi pada bilangan gelombang 1374 cm-1, yaitu ikatan hubung sialng antara kitosan-STPP pada busa poliuretan. Dari hasil penelitian ini disimpulkan bahwa pada variasi waktu curing 75 menit dan suhu 135 C merupakan kondisi yang optimum untuk proses curing. Hal ini dibuktikan dengan meningkatnya kekuatan tarik sebesar 4.2 serta nilai resiliansi sebesar 2.5, juga disertai dengan menurunya nilai elongasi sebesar 24 dan nilai kekedapan udara sebesar 26. Nilai stabilitas termalnya juga meningkat dimana dibuktikan dengan meningkatknya persen berat sampel tersisa yaitu 13 dengan suhu degradasi yang lebih rendah yaitu 360 C.

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At this time research on polyurethane foam is centered on efforts to improve the characteristics of foam stiffness by selecting raw materials and renewable processes.Chitosan bio-coating is a linear polysaccharide which is a derivative product of chitin, the outermost constituent of anthropoid animals such as shrimp, crabs, and insects. The cross linking between polyurethane foam and chitosan is proven from SEM observations where the formation of layers on the surface and pores of the foam pores. Then the FTIR test which shows the curing phenomenon occurs at wave number 1374 cm-1, namely the bonding relationship between chitosan-STPP on polyurethane foam. From the results of this study concluded that the variation of 75 minutes curing time and 135 C temperature is the optimum condition for the curing process. This is evidenced by an increase in tensile strength of 4.2 and a resilience value of 2.5, also accompanied by a decline in the elongation value of 24 and an airtight value of 26. The thermal stability value also increases which is evidenced by the increase in the remaining percent weight of the sample by 13 with a lower degradation temperature of 360."

"ABSTRAKTeknologi Thermal Spray Aluminium TSA telah banyak diaplikasikan pada industri Minyak dan Gas terutama sebagai pelindung terhadap korosi. Sebagai pelindung korosi, sifat mekanis seperti kekuatan ikatan adesif dan kohesif material pelapis berkaitan langsung dengan umur ketahanan terhadap korosi. Pada penelitian ini telah dilakukan pengamatan pengaruh waktu tunda proses pelapisan aluminium terhadap karakteristik sifat mekanis lapisan.Proses pelapisan aluminium pada penelitian ini menggunakan metode Thermal Arc Spray dengan material substrat baja karbon SK5 dan material pelapis kawat aluminium 95.5 , dilakukan secara bertahap dengan memberikan waktu tunda 0 jam tanpa waktu tunda , 4 jam, 24 jam dan 48 jam. Ketebalan lapisan TSA awal 75-125 ?m, dan ketebalan lapisan TSA setelah diberikan waktu tunda sebesar 200-250 ?m. Sampel dilakukan pengujian daya lekat pull-off test , tekuk bending test , kekerasan mikro, pengamatan metalografi menggunakan mikroskup optic dan SEM.Proses pelapisan TSA dengan disertai waktu tunda 4 jam, 24 jam dan 48 jam menghasilkan tingkat porositas yang lebih tinggi pada lapisan dibandingkan dengan tanpa waktu tunda, namun variabel perbedaan waktu tunda tidak mempengaruhi tingkat porositas. Tingkat porositas tersebut berpengaruh pada kekuatan ikatan adesif dan kohesif lapisan. Dari hasil pengujian daya lekat lapisan didapatkan sampel tanpa waktu tunda menghasilkan kekuatan ikatan 8,3 MPa, sedangkan sampel yang diberikan waktu tunda 4 jam, 24 jam dan 48 jam mengalami kegagalan adesif dan kohesif dengan kekuatan daya lekat 8 MPa, 8 MPa, dan 7,9 MPa. Pada sampel dengan waktu tunda, lapisan TSA pertama akan bertindak sebagai permukaan substrat bagi lapisan TSA kedua. Tingkat kekasaran dan profil permukaan lapisan TSA pertama sebesar 126,3 ndash; 153 ?m akan menghasilkan tingkat porositas lapisan TSA keseluruhan yang lebih tinggi dibandingkan proses tanpa waktu tunda.

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ABSTRACTThermal Aluminum Spray TSA has been widely applied in oil and gas industries especially as a protection against corrosion. As a corrosion protector, mechanical properties of coating materials such as adhesive and cohesive bond strength are directly related to the life time of corrosion resistance. In this research has been observed the influence of time delay of aluminum coating process on the coating mechanical properties.The aluminium coating process in this research using Thermal Arc Spray as the method with SK5 carbon steel substrat and 95.5 aluminum wire coating material. Coating process has been done in 2 stages with 0 hours, 4 hours, 24 hours and 48 hours time delay. The first layer thickness is 75 125 m, and after a given delay time is 200 250 m. Coated samples were tested by pull off test, bending test, micro hardness and metallographic observation using optical microscope and SEM.TSA within 4 hour, 24 hour and 48 hour time delay coating process produces higher porosity levels in the coating compared without time delay, however delay time difference variable did not affect the porosity level. Furthermore, porosity level will affect the adhesive and cohesive bond strength of the coating. From the Pull off testing, sample without delay time resulting 8,3 MPa bond strength, and samples with 4 hours, 24 hours and 48 hours delay time resulted bond strength of 8 MPa, 8 MPa and 7,9 MPa. For sample with time delay, the first TSA coating layer will act as a substrate surface for the second TSA layer. Thus, the surface roughness level of the first TSA coating layer of 126,3 ndash 153 m will resulting higher porosity for overall TSA coating layer than the process without time delay."

"Baja Tahan Karat 316L memiliki aplikasi yang sangat beragam, mulai dari platform serta instalasi lainnya, terutama pada lepas pantai karena ketahanan korosinya yang tinggi. Namun, pada penggunaannya, baja tahan karat 316L memiliki kemungkinan untuk terjadi korosi sumuran. Korosi sumuran merupakan korosi yang sulit untuk dideteksi sampai akhirnya terjadi kerusakan. Dengan mengaplikasikan pelapisan aluminium pada baja tahan karat 316L maka korosi sumuran dapat dicegah. Selain itu, ketahanan korosi secara umum juga akan meningkat. Metode untuk mengaplikasikan aluminium pada baja tahan karat 316L adalah dengan electric arc thermal spray aluminum. Pengujian kali ini menginvestigasi ketebalan pelapisan paling baik yang memberikan hasil maksimal, dengan tiga parameter yaitu berkisar antara 90-100 µm, 140-150 µm, and 190 – 200 µm. Ketahanan korosi diuji menggunakan metode polarisasi siklik. Hasil studi menunjukkan bahwa ketahanan korosi dan daya lekat paling baik dihasilkan lapisan dengan ketebalan 190 – 200 µm

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In oil and gas industries, 316L Stainless Steel is widely used to construct platforms and other installations because of its high corrosion resistance. However, 316L Stainless Steel is still susceptible to pitting corrosion which is difficult to be detected before failure starts to happen. By applying aluminium coating on stainless steel, pitting corrosion will be prevented. Moreover, the corrosion rate will decrease and the steel’s lifetime will increase. Using Electric Arc Thermal Spray Aluminium as the method to apply the aluminium, one of the most important factor that influence corrosion rate on aluminium coated stainless steel is the thickness itself. This paper investigates the most effective thickness applied to achieve the best quality of the coating, ranging at 90-100 µm, 140-150 µm, and 190 – 200 µm. The corrosion resistance is tested using the data obtained from the cyclic polarization curve. The study shows that the coating thickness of 190 – 200 µm produces the best corrosion resistance and adhesion strength

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"Skripsi ini membahas mengenai pengaruh perbandingan rasio air-prekursor terhadap kuat tekan beton geopolimer pada beberapa penelitian. Analisa dilakukan berdasarkan data yang sudah dikelompokkan dan kemudian diolah dengan cara menghitung nilai rasio air-prekursor pada tiap variasi campuran. Pengelompokan data dilakukan berdasarkan faktor yang mempengaruhi nilai air prekursor yaitu kadar air dan zat Admixture. Dan perhitungan nilai rasio air-prekursor dilakukan dengan cara membagi berat air tambahan (extra water) dengan berat prekursor, tanpa menghitung kandungan air yang berasal dari aktivator. Hasil yang diperoleh adalah nilai air-prekursor dan komposisi campuran beton geopolimer yang menghasilkan kuat tekan paling tinggi pada tiap pengelompokan data. Selain itu, dilakukan juga penelitian laboratorium pada pasta geopolimer dengan prekursor abu terbang dan abu sekam padi.

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This mini thesis discusses about the effect of water-precursor ratio to compressive strength geopolymer concrete in several studies. The analysis was made based on data that has been classified and then processed by calculating the ratio of waterprecursor mixture in each variation. Grouping data is based on the factors that affect the value of water precursor substance water content and admixture. And calculating the ratio of water-precursor conducted by dividing the additional weight of water (the extra water) with a weight of precursors, without calculating the water content derived from the activators. The main result is the value of water-precursor and the composition of geopolymer concrete mixture that produced the highest compressive strength at each grouping of data. In addition, laboratory analysis showed that the precursor pastes with fly ash geopolymer and rice husk ash."

"Beton merupakan material penting yang banyak digunakan dalam pembangunan infrastruktur. Sehingga penggunaan semen sebagai bahan dasar pengikat beton juga akan semakin meningkat setiap tahunnya. Namun yang harus diperhatikan dalam proses produksi semen ini ialah terjadinya pelepasan karbon dioksida (CO2) yang sangat banyak ke atmosfer dan dapat menyebabkan kerusakan lingkungan. Untuk mengatasi permasalahan tersebut dibutuhkan material lain sebagai bahan pengganti semen yang lebih ramah lingkungan. Beton geopolimer merupakan salah satu alternatif untuk menggantikan beton yang berbahan dasar semen sebagai material yang kurang ramah lingkungan. Pembuatan beton geopolimer tidak menggunakan semen sebagai bahan pengikat melainkan menggunakan Abu Terbang (Fly Ash) sebagai penggantinya yang kaya akan Silika dan Alumina dan dapat bereaksi dengan cairan alkalin untuk menghasilkan bahan pengikat (binder). Penggunaan silica fume sebesar 10% dalam campuran pasta juga akan diamati dalam pengaruh terhadap sifat mekanik beton setelah beton direndam dalam lingkungan air danau selama 1 bulan. Tes kuat tekan menggunakan sampel berbentuk silinder 15x30cm dengan curing selama 72 jam pada suhu 800C dilakukan untuk membandingkan setiap benda uji dari komposisi silica fume dan juga kondisi lingkungan yang berbeda. Hasil studi menunjukkan bahwa kuat tekan beton dipengaruhi oleh penambahan 10% silica fume dan juga dalam kondisi perendaman di air danau. Nilai kuat tekan beton geopolimer tanpa silica fumesebelum perendaman memiliki kekuatan rata-rata 23,65 MPa dan menurun setelah direndam dalam air danau sebesar 9,20 MPa menjadi 14,45 Mpa. Sedangkan kuat tekan beton geopolimer dengan penambahan 10% silica fume sebelum perendaman memiliki kekuatan rata-rata 11,82 MPa dan meningkat setelah direndam dalam air danau sebesar 6 MPa menjadi 17,80 MPa. Selain itu uji XRD juga dilakukan pada beton setelah perendaman untuk mengetahui unsur-unsur yang terbentuk pada beton ketika berada di lingkungan air danau. Hasil XRD menunjukkan adanya kandungan kuarsa dan microcline (KAlSi3O8) pada beton dengan penambahan 10% silica fume. Microcline sendiri memiliki nilai kekuatan yang baik pada skala Mohs yaitu sebesar 6 (orthoclase). Sedangkan hasil XRD pada beton geopolimer tanpa penambahan silica fumedidapatkan kandungan kuarsa, microcline(KAlSi3O8), calcite (CaCO3) dan CSH (Calcium Silicate Hydrate). Adanya kandungan calcite (CaCO3) dan CSH menunjukkan terperangkapnya udara pada beton dan juga perembesan air yang terjadi yang menyebabkan terjadinya reaksi hidrasi sehingga dapat menurunkan kekuatan beton geopolimer setelah perendaman.

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Concrete is an important material and widely used in building construction. Therefore, the use of cement as concrete binder will also increase within the next few years. However, the release of Carbon Dioxyde during the production of cement can be harmful for environment. To overcome this difficulty, another material is needed to replacement. Geopolymer concrete is one of the alternative materials that can be used without any side effects towards environment. Cement is not used during the production of Geopolymer Concrete. Instead, Fly Ash is used as a binder because of its richness in Silica and Alumina and its capability to react with alkaline solution to produce a binder. The use of silica fume amounting to 10% of the mixture will also be observed on its effects towards the mechanical properties of geopolymer concrete that was submerged inside the fresh water lake for a month. Compressive strength tests using samples of cylindrical 15x30cm with curing for 72 hours at a temperature of 800C was performed to compare each samples of geopolymer concrete with difference in silica fume composition and different environmental condition. The compressive strength of geopolymer concrete without silica fume before immersion has an average of 23.65 MPa and decreased after immersion in water lake at 9.20 MPa to 14.45 MPa. While the geopolymer concrete compressive strength with the addition of 10% silica fume before immersion has an average power of 11.82 MPa and increased after immersion in water lake by 6 MPa to 17.80 MPa. XRD test was also conducted after submerging the geopolymer concrete to analyze elements that was formed when the concrete was being submerged inside the lake. XRD results showed the content of quartz and microcline (KAlSi3O8) in geopolymer concrete with the addition of 10% silica fume. Microcline itself has good hardness on the Mohs scale is equal to 6 (orthoclase). While the results of XRD on geopolymer concrete without the addition of silica fume content of quartz, microcline (KAlSi3O8), calcite (CaCO3) and CSH (Calcium Silicate Hydrate). The content of calcite (CaCO3) and CSH showed air trapping in the concrete and water seepage that occurs the causes of hydration reaction so as to reduce the strength of geopolymer concrete after soaking."

"[ ABSTRAK Kaca merupakan sumber silika amorphous yang baik serta memiliki komposisi kimia dan reaktivitas yang tepat untuk melakukan reaksi Pozzolan. Sehingga muncul lah ide untuk menggunakan kaca sebagai agregat kasar pada beton. Pada penelitian ini, sampel yang dibuat adalah dua jenis beton, yaitu Portland dan Geopolimer dengan variasi substitusi kaca sebanyak 0%, 25%, 50%, 100%. Pengujian yang dilakukan adalah uji tekan dan pengamatan foto makro. Komposisi beton, sejarah perlakuan, dan suhu curing memberi pengaruh signifikan pada nilai kuat tekan yang dihasilkan. Kesimpulan yang didapatkan adalah beton Portland dan beton geopolimer dengan substitusi kaca sebesar 50% memiliki kuat tekan tertinggi, dan pasta geopolimer dapat melekat pada kaca namun pasta semen tidak.

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ABSTRACT

Glass are good source of amorphous silica and it also has good chemistry composition and precise reactivity to make Pozzolan reaction. So there was an idea to use glass as coarse aggregate in concrete. In this research, two types of concrete will be made, which are Portland concrete and geopolymer concrete with variation of waste glass substitution as much as 0%, 25%, 50%, 100%. The conducted tests are pressure test and macro photos observations. Concrete composition, treatment history, and curing temperature gave significant influence on their compressive strength. The conclusions are both portland and geopolymer concrete with 50% waste glass substitution has the highest compressive strength, and geopolymer paste could adhered to glass but cement paste could not.;Glass are good source of amorphous silica and it also has good chemistry composition and precise reactivity to make Pozzolan reaction. So there was an idea to use glass as coarse aggregate in concrete. In this research, two types of concrete will be made, which are Portland concrete and geopolymer concrete with variation of waste glass substitution as much as 0%, 25%, 50%, 100%. The conducted tests are pressure test and macro photos observations. Concrete composition, treatment history, and curing temperature gave significant influence on their compressive strength. The conclusions are both portland and geopolymer concrete with 50% waste glass substitution has the highest compressive strength, and geopolymer paste could adhered to glass but cement paste could not.;Glass are good source of amorphous silica and it also has good chemistry composition and precise reactivity to make Pozzolan reaction. So there was an idea to use glass as coarse aggregate in concrete. In this research, two types of concrete will be made, which are Portland concrete and geopolymer concrete with variation of waste glass substitution as much as 0%, 25%, 50%, 100%. The conducted tests are pressure test and macro photos observations. Concrete composition, treatment history, and curing temperature gave significant influence on their compressive strength. The conclusions are both portland and geopolymer concrete with 50% waste glass substitution has the highest compressive strength, and geopolymer paste could adhered to glass but cement paste could not.;Glass are good source of amorphous silica and it also has good chemistry composition and precise reactivity to make Pozzolan reaction. So there was an idea to use glass as coarse aggregate in concrete. In this research, two types of concrete will be made, which are Portland concrete and geopolymer concrete with variation of waste glass substitution as much as 0%, 25%, 50%, 100%. The conducted tests are pressure test and macro photos observations. Concrete composition, treatment history, and curing temperature gave significant influence on their compressive strength. The conclusions are both portland and geopolymer concrete with 50% waste glass substitution has the highest compressive strength, and geopolymer paste could adhered to glass but cement paste could not.;Glass are good source of amorphous silica and it also has good chemistry composition and precise reactivity to make Pozzolan reaction. So there was an idea to use glass as coarse aggregate in concrete. In this research, two types of concrete will be made, which are Portland concrete and geopolymer concrete with variation of waste glass substitution as much as 0%, 25%, 50%, 100%. The conducted tests are pressure test and macro photos observations. Concrete composition, treatment history, and curing temperature gave significant influence on their compressive strength. The conclusions are both portland and geopolymer concrete with 50% waste glass substitution has the highest compressive strength, and geopolymer paste could adhered to glass but cement paste could not., Glass are good source of amorphous silica and it also has good chemistry composition and precise reactivity to make Pozzolan reaction. So there was an idea to use glass as coarse aggregate in concrete. In this research, two types of concrete will be made, which are Portland concrete and geopolymer concrete with variation of waste glass substitution as much as 0%, 25%, 50%, 100%. The conducted tests are pressure test and macro photos observations. Concrete composition, treatment history, and curing temperature gave significant influence on their compressive strength. The conclusions are both portland and geopolymer concrete with 50% waste glass substitution has the highest compressive strength, and geopolymer paste could adhered to glass but cement paste could not.]"