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This paper describes an investigation of the events when sub-sea pipeline is impacted by submarine slide. Investigations are carried out by developing the model in the laboratory in the form of a collision between sub-aqueous mudflow with a pipe stem. Gravity flow concepts of fluid mechanics principles and lock-exchange system are adopted to build the laboratory experiment. It is implemented into a set of equipment of rectangular channel to generate the simulation of mudflow in water ambient. A crosswise pipe stem positioned at certain run-out distance is collided by mud flow. Mud model used is slurry of kaolin clay-water mixtures. The collision attributes of the collision event is including velocity, Reynolds number, maximum drag force exerted by mudflow, and drag force coefficient. All are observed based on percentage of kaolin clay content. The series of experiments is representing the estimation of drag forces exerted by muddy submarine slide on pipeline in the prototype condition.

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Utilization waste material on concrete ingredients or its manufacturing that did not harm the environment is the need for the environment sustainability. It is the background of research in concrete design for more environmental friendly as often called green concrete. This work aims to investigate the usability of the melted slag, obtained from local wrought iron industry, as aggregates replacement according to waste material utilization. In particular, it focused on studying the feasibility of replacing the aggregates using melted slag by investigating the basic physical characteristic. Slag is known have a high percentage of silica and ferric oxides, which gives pozzolanic activities that suitable to use as cement blended product. Slag waste used in this work is obtained from the wrought iron industry from Pakis district, Magelang Regency, Central Java, Indonesia. The slag chunk extracted from the furnace then crushed to smaller particle sizing as fine aggregates and coarse aggregates. The aggregates characteristic is observed in relation to gradation test, specific gravity, bulk density, clay lumps percentage, and Los Angeles abrasion value. All of observation parameters are taken consecutively based on SNI and ASTM specification to evaluate its compatibility as concrete aggregates. The current work remarks that the fine and coarse aggregates generated from wrought iron slag do not reveal complete fulfilment in the aggregate specifications of any standard. Even though, the slag fine aggregates could be used in standard or lightweight concrete with further treatment such as crushing to smaller particle size, washing to minimize the clay lumps, and mixing with natural aggregates.

Teknik pengukuran kualitas beton dapat dideteksi dengan mengetahui besarnya kecepatan perambatan gelombang ultrasonik. Dalam prosesnya, akurasi hasil pengukuran ditentukan oleh jarak transducer dan receiver, mutu material, impedansi akustik material, dan salah satunya homogenitas material. Hingga kini, metode yang populer digunakan adalah direct dan indirect untuk mengetahui kualitas material dan deteksi kerusakan pada beton. Salah satu kendala utama yang dihadapi adalah ketika kedua metode tersebut tidak dapat digunakan disebabkan kondisi eksisting Gedung. Skema uji semi-direct diusulkan untuk membantu menyelesaikan permasalahan yang tidak dapat dijangkau oleh metode direct dan indirect. Hasil akhir pengujian menunjukkan tingkat akurasi yang lebih rendah dibandingkan metode yang lainnya dengan selisih hasil pengujian 30%.