ANALISA PENGARUH AKTIVATOR KALIUM DAN KONDISI MATERIAL PADA BETON GEOPOLYMER DARI LIMBAH B3 FLY ASH BATUBARA TERHADAP KUAT TEKAN

Beton Geopolymer merupakan beton ramah lingkungan yang mana bahan utama yang digunakan memanfaatkan limbah B3 fly ash Batubara yang dijadikan sebagai pengganti semen. Material yang digunakan dalam penelitian ini dilakukan pemanasan dengan oven. Dan aktivator yang digunakan sebagai pembentuk beton geopolymer adalah Kalium. Tujuannya untuk mengetahui pengaruh aktivator untuk mencapai mutu beton yang di rencanakan berupa beton ringan dengan mutu yang tinggi. Sehingga penelitian ini dapat dijadikan pedoman dalam pembuatan beton ringan dengan mutu tinggi dan ramah lingkungan. Adapun secara spesifik tujuan yang ingin diketahui berapa besar perbedaan mutu beton geopolymer yang menggunakan aktivator Kalium dengan prilaku semua material kering oven. Dengan Mutu beton rencana 30 Mpa, pengujian di laboratorium Fakultas Teknik Sipil Universitas Bina Darma Palembang dengan membuat 18 benda uji silinder diameter 100 mm x 200 mm. Pembuatan benda uji dilakukan kondisi material aggregat dalam kondisi Saturated Surface Dry (SSD) dan kering oven pada suhu 60°C dengan waktu 1 jam, dengan perawatan benda silinder dengan suhu ruangan sampai waktu benda uji akan di uji. Produk penelitian yang dilakukan adalah grafik hubungan perilaku material kondisi SSD dan kering oven pada material beton gopolymer dengan aktivator Kalium dalam menerima beban tekan. Dari grafik tersebut dapat dilihat pengaruh kondisi material dan aktivator Kalium sebagai material beton geopolymer dalam menerima beban tekan dengan nilai kuat tekan fc 30 Mpa.

PENGARUH KONDISI MATERIAL DENGAN AKTIVATOR POTASSIUM PADA BETON GEOPOLYMER DARI LIMBAH B3 FLY ASH BATUBARA TERHADAP KUAT TEKAN

Pada umumnya beton dikenal material yang tersusun dari komposisi utama batuan (aggregat) kasar, pasir, air dan semen. Karena persediaan semen yang semakin berkurang, berbagai penelitian telah dilakukan untuk mencari material yang ramah lingkungan sebagai pengganti semen. Pada penelitian ini membahas tentang beton geopolymer berbasis abu terbang (fly ash) hasil pembakaran batu bara pada PLTU Bukit Asam Tanjung enim Sumatera Selatan dengan aktivator potassium. Penelitian ini dilakukan untuk mengetahui pengaruh aktivator pottasium dan kondisi material, terhadap kuat tekan rencana 30 Mpa pada beton geopolymer melalui pengujian di laboratorium Fakultas Teknik Sipil Universitas Bina Darma Palembang dengan membuat 18 benda uji silinder diameter 100 mm x 200 mm, dengan fly ash dan aktivator Pottasium. Pembuatan benda uji dilakukan kondisi material aggregat dalam kondisi Saturated Surface Dry (SSD) dan kering oven pada suhu 60°C dengan waktu 1 jam, dengan perawatan benda silinder dengan suhu ruangan sampai waktu benda uji akan di uji. Produk penelitian yang dilakukan adalah grafik hubungan perilaku material kondisi SSD dan kering oven pada material beton gopolymer dalam menerima beban tekan dengan aktivator Pottasium. Dari grafik tersebut dapat dilihat bahwa, dengan kondisi material kering oven dari fly ash dan aktivator pottasium, lebih kuat dalam menerima beban tekan dengan nilai kuat tekan fc 30 Mpa.

Effects Superplasticizer Type and Dosage on The Properties of Reactive Powder Concrete

Superplasticizer is one of the most common types of chemical admixtures used in the mortar or concrete, especially that characterized high performance like Reactive powder concrete. Recently, the chemical admixture is considered as one of the main components of cement-based products due to it has a significant role to improve the physical and mechanical properties generally. Therefore, the experimental work of this research has been an attempt to study the influence of two types of superplasticizers with different dosages on the properties of reactive powder concrete. The workability, compressive strength, and saturated surface dry density of reactive powder concrete used two types of chemical admixture(superplasticizer) individual and in combination have been studied and compared together. The results indicated that the use of superplasticizer type ViscoCrete-5930 in individual or combination with superplasticizer type KUT PLAST PCE600 has a positive impact on the properties of reactive powder concrete especially its flowability and compressive strength. Keywords:Reactive powder concrete; Superplasticizer; Flowability; Compressive strength; Saturated surface dry density;

Hopanoid lipids may facilitate aerobic nitrogen fixation in the ocean

Cyanobacterial diazotrophs are considered to be the most important source of fixed N2in the open ocean. Biological N2fixation is catalyzed by the extremely O2-sensitive nitrogenase enzyme. In cyanobacteria without specialized N2-fixing cells (heterocysts), mechanisms such as decoupling photosynthesis from N2fixation in space or time are involved in protecting nitrogenase from the intracellular O2evolved by photosynthesis. However, it is not known how cyanobacterial cells limit O2diffusion across their membranes to protect nitrogenase in ambient O2-saturated surface ocean waters. Here, we explored all known genomes of the major marine cyanobacterial lineages for the presence of hopanoid synthesis genes, since hopanoids are a class of lipids that might act as an O2diffusion barrier. We found that, whereas all non−heterocyst-forming cyanobacterial diazotrophs had hopanoid synthesis genes, none of the marineSynechococcus,Prochlorococcus(non−N2-fixing), and marine heterocyst-forming (N2-fixing) cyanobacteria did. Finally, we conclude that hopanoid-enriched membranes are a conserved trait in non−heterocyst-forming cyanobacterial diazotrophs that might lower the permeability to extracellular O2. This membrane property coupled with high respiration rates to decrease intracellular O2concentration may therefore explain how non−heterocyst-forming cyanobacterial diazotrophs can fix N2in the fully oxic surface ocean.

PASIR VULKANIK SEBAGAI BAHAN STABILITAS CAMPURAN GENTING BETON (STUDI EXSPERIMEN GRADASI PASIR GUNUNG KELUD PADA RADIUS 200 KM DI KOTA CARUBAN)

Genting is a utility roof materials above the building that serves as a protective weather and channeling rain water that was on it down. Alternative yangb concrete tiles is done more efficiently without the combustion process. Kelud the ash sand fly bergradai to the distance, in other words the farther the distance of the small grain diameter at a given radius. The heat caused by the Volcanic magma, ash makes Kelud Sand has a high water absorption, but will have saturated and rejected, resulting in bledding. By mixing sand times as a species, then an increase hidroulis and mechanical properties of an ideal mix ratio. From the experiment results for the compressive strength of the mixture 2: 2: 1 is stronger ie max 108.00 kg /cm2, a mixture of 3: 2: 1 compression stress value obtained sbesar 64.00 kg /cm2 and the mixture of 4: 2: 1 obtained compressive stress value of 24.00 kg /cm2. As for the bending stress fracture to a mixture of 2: 2: 1 max values obtained at 33.5 kg / cm2and for a mixture of 3: 2: 1 max values obtained at 23.33 kg /cm2 while for mixture 3: 2: 1 obtained value max of 5.33 kg /cm2, and water absorption in the saturated surface dry condition for a mixture of 2: 2: 1 obtained 10.23%, water absorption in the saturated surface dry condition for a mixture of 3: 2: 1 obtained 11.82 %, water absorption on the condition of saturated surface dry to mix 4: 2: 1 obtained 12.81%,. Then for mains water tembur can be seen in the discussion section, but can be inferred to mix 2: 2: 1 is more dense because Crystal showed a copy with a little water and a relatively dry and to a mixture of 4: 2: 1 indicates a copy with softer water crystals and evenly with a small diameter, both assessed at the time of maximum concentration, while for the mixture 3: 2: 1 is more porous at the same time. Keywords: genting concrete, hydraulic properties, volcanic gradient, mixed ideal