GUNITECH®: An Innovative Pumice Based Dry Shotcrete Application

Pumice quarried by LAVA MINING AND QUARRYING SA from Yali Island, Dodecanese, is used in domestic and foreign markets mainly as concrete lightweight aggregate, masonry unit constituents, road substrate, and loose soil stabilization. It is a porous natural volcanic rock with low density, low thermal and noise transmission, and the highest strength among all the natural or artificial lightweight materials of mineral origin. Nowadays, pumice is of additional interest as it has a reduced CO2 footprint because thermal energy is not needed for its expansion compared with the artificial lightweight aggregates. In this context, HERACLES GROUP in collaboration with Sika Hellas has launched a new product containing pumice stone under the brand name GUNITECH®. GUNITECH® is an innovative bagged material for spraying concrete applications. It is a ready lightweight concrete, for building repairs certified as EN 1504-3.

Immobilization of Providencia stuartii Cells in Pumice Stone and Its Application for N-Acetylglucosamine Production

Research background. Shrimp shells contain chitin that can further be processed into N-acetylglucosamine which has been extensively used to treat joint damage. Providencia stuartii isolated form previous research has strong chitinolytic activity and may be utilized in the form of immobilized cells to be used in repeated fermentation. Pumice is a porous and rigid stone that offers superior mechanical strength, making it suitable to be used for immobilization process. Experimental approach. The research used experimental method to conduct the submerged fermentation process with different pumice stone size and pumice stone:growth medium ratio (m/V). The fermentation was carried out for 4 days at 37 C and pH of 7.0. The optimum pumice stone size and pumice stone:growth medium ratio (m/V) were used to determine the optimum fermentation cycle to produce N-acetylglucosamine. Results and conclusions. Pumice stones of 1.0×1.0×1.0 cm and pumice stone:growth medium ratio (m/V) of 1:5 were found to be the optimum conditions which successfully immobilized (89.99±1.65) % cells and produced (331.37±7.34) g/L N-acetylglucosamine. The highest N-acetylglucosamine concentration of (322.97±2.46) g/L was obtained in the first fermentation cycle which then decreased and remained stable throughout the last three cycles of fermentation. Novelty and scientific contribution. P. stuartii was a strong chitinolytic bacteria previously isolated from rotten shrimp shells and was used for the first time in immobilized form to produce N-acetylglucosamine. The findings in this research showed potential use of P. stuartii cells immobilized in pumice stone for continuous production of N-acetylglucosamine using fermentation method.

Partial Replacement of Pumice Stone in Concrete As Coarse Aggregate Material

In design of concrete structures, concrete plays an important role in the contemporary background as raw material for construction has been decreased. Therefore construction industry has acquaint with novel methods by making use of the available waste material for partial replacement by using alternative aggregates instead of ordinary aggregates. In this study, pumice stone is used as replacement materials for concrete where it is found in the abyssal of the red clay or in deepest portion of the ocean, and partially replacing by Pumice, blends with cement. The physical, mechanical and durability properties of concrete was investigated by conduction compressive strength and tensile strength on the ordinary and replaced concrete with varied percentage of pumice from 5% to 30%. It’s obsereved that environmental and economical benefits can be achieved if waste materials can be used to replace the coarse aggregate in order to use the waste materials effectively in areas with abundant availability of materials. This thesis work on the effectiveness of partial substitutions of pumice for coarse aggregate in producing adequate strength gain. In the present thesis work comparison of fresh concrete and hardened properties of concrete for both conventional concrete and Replaced concrete for varying percentage of replacement of pumice stone to coarse aggregate and based on the experimental results, it’s concluded that 25% partial replacement by pumice gives maximum compresive strength.

Study of Light Weight Fibre Reinforced Concrete by Partial Replacement of Coarse Aggregate with Pumice Stone

As the demand for the structural members application in the concrete industry is continuously increasing simultaneously many a times it is required to lower the density of concrete enabling light weight which helps in easy handling of the concrete and its members. In this research an experimental endeavour has been made to equate conventional concrete with light weight by partially substituting the coarse aggregate with the pumice stone aggregate in M30 grade mix design. Simultaneously small fibres of Recron3's Polypropylene have been applied to the concrete as a reinforcing medium to minimize shrinkage cracking and improve tensile properties. The coarse aggregate was substituted by the pumice aggregate in 10, 20, 30, 40, and 50 percent and fibres respectively in 0.5, 1, 1.5, 2 and 2.5 percent. The experiment is focused on strength parameters to determine the most favourable optimum percent with respect to conventional concrete. Keywords: OPC (Ordinary Portland Cement)1, FA (Fine Aggregate)2, CA (Coarse Aggregate) 3, fck (Characteristic Compressive Strength at 28days)4, Sp. Gr (Specific Gravity)5, WC (Water Content)6, W/C (Water Cement Ratio)7, S (Standard Deviation)8, Fck (Target Average Compressive Strength at 28days)9.

UMPAK BATU: JEJAK KONSTRUKSI BANGUNAN MASA LAMPAU DI LAMPUNG BARAT [ COLUMN BASE : THE TRACES OF ANCIENT BUILDING CONSTRUCTION IN WEST LAMPUNG]

Rumah adalah kebutuhan dasar manusia yang dibangun dengan berbagai bahan, teknik, dan sistem kepercayaan dan sekaligus menggambarkan identitas dan status sosial pemiliknya. Rumah merupakan kesatuan dari struktur bangunan yang terdiri dari konstruksi dasar, konstruksi tubuh, dan konstruksi atap. Setiap kelompok masyarakat memiliki konstruksi bangunan yang berbeda-beda yang mencerminkan kondisi geografis dan lingkungan setempat. Penelitian arkeologi di Daerah Aliran Sungai (DAS) Way Semangka, Kabupaten Lampung Barat menemukan lebih dari empat puluh batu tufa dan batu apung di enam situs arkeologi di Liwa. Batu-batu tersebut memiliki beragam bentuk dan ukuran yang belum diketahui fungsinya. Tulisan ini bertujuan mengetahui fungsi batu-batu tersebut kaitannya dengan bangunan tradisional Lampung. Penelitian dilakukan dengan metode survei arkeologi, deskripsi, dan perbandingan data etnografi. Hasil penelitian memperlihatkan ada persamaan karakteristik batu pada bangunan rumah-rumah tradisional di Liwa, Kenali, dan Canggu dengan artefak batu yang ditemukan di situs-situs arkeologi di DAS Way Semangka. Batu-batu tersebut diasumsikan sisa umpak atau batu pondasi dari struktur bangunan tradisional Lampung yang dibuat dengan teknik konstruksi tradisional kalindang yang tahan gempa. Umpak batu dari batuan tufa dan batu apung terbilang unik karena ringan, mudah dibentuk, dan memiliki keunggulan sebagai bahan beton ringan. Penggunaan batuan tufa dan apung sebagai umpak bangunan, merupakan bukti kearifan lokal yang masih dilestarikan di Lampung Barat. House as a basic need was built with various materials, techniques, and the belief system of the supporting community, as well as describe the identity and social status of the owner. A house is a unit of the building structure that generally consists of basic construction, body, and roof construction. Each community group has a different building construction and can also reflect their geographical and climatic conditions. Archaeological research in the Way Semangka Watershed (DAS), West Lampung Regency, found more than forty stones of tuf and pumice in six archaeological sites in Liwa. The stones have various shapes and sizes whose function is not yet known. This paper aims to determine the utility of these stones in traditional Lampung buildings. The research was conducted using archaeological survey methods, descriptions, and a comparison of ethnographic data. The results showed similarities in the characteristics of the stones in the traditional houses in the Liwa, Kenali, and Canggu areas, with stone artefacts found at archaeological sites in the Way Semangka watershed. These stones are assumed to be remnants of the column base of traditional Lampung building structures made with the Kalindang technique of which is traditionally earthquake-resistant construction. The tuf and pumice stone are unique because it is light, shapeable and it has the advantage of being a lightweight concrete material. The use of tuf and pumice stone as a column base is evidence of local wisdom preserved in West Lampung.

SINTESIS ZEOLIT DARI BATU APUNG (PUMICE) DAERAH IJOBALIT LOMBOK TIMUR SEBAGAI ADSORBEN LOGAM Fe

ABSTRAKAktivitas letusan besar Gunung Api Samalas di Lombok meninggalkan jejak mineral batuan beku salah satunya batu apung (pumice). Batu apung memiliki komposisi mineral utama berupa silika sebanyak 58,3%. Tujuan dari penelitian untuk identifikasi karakteristik zeolit dari batu apung sebagai adsorben logam Fe. Zeolite disintesis menggunakan metode kopresipitasi. Identifikasi gugus fungsi, kristalinitas, dan struktur kristal zeolite sintesis menggunakan FTIR dan XRD. Sedangkan analisis adsorbsi menggunakan AAS. Zeolit berhasil terbentuk dari sintesis batu apung ditandai dengan kemunculan gugus fungsi TO4 dan gugus fungsi Si-O-Si pada panjang gelombang 983,85 cm-1 dan 660,02 cm-1. Zeolit yang terbentuk dari proses sintesis batu apung yaitu tipe zeolit ZK-14 dengan struktuk kristal kubik. Adapun hasil analisis kemampuan adsorbs dari zeolite ZK-14 ini sangat baik mencapai 99,22% pada komposisi Si/Al pada 25/30. Sehingga sintesis batub apung menjadi zeolite dapat diaplikasikan sebagai penyerap logam Fe. Kata kunci: Adsorben; Batu Apung; Zeolit. ABSTRACTThe massive eruption activity of the Samalas Volcano in Lombok left traces of igneous rock minerals, one of which was pumice. The pumice has a main mineral composition of 58.3% silica. The purpose of this study is to identify the characteristics of zeolite from pumice as an adsorbent of Fe metal. Zeolite has been synthesized using a coprecipitation method. The identification of functional groups, crystallinity, and crystal structure of synthetic zeolite using FTIR and XRD. Meanwhile, AAS was implemented for the adsorption analysis. The zeolite was successfully formed from the synthesis of pumice characterized by the appearance of the TO4 functional group and the Si-O-Si functional group at wavelengths of 983.85 cm-1 and 660.02 cm-1. The zeolite fabricated from the pumice synthesis process is ZK-14 type zeolite with a cubic crystal structure. The examination results from the adsorption ability of zeolite ZK-14 are very good, reaching 99.22% at the Si/Al composition at 25/30. In fact, the synthesis of pumice into zeolite can be applied as an absorber of Fe metal. Keywords: Adsorbent; Pumice Stone; Zeolite.