Penggunaan cangkang kerang darah asal Pasar Kobong Semarang sebagai agregat dalam pembuatan beton non pasir

OKTARINA, Devi, Dr.Ir. Iman Satyarno, ME

2007 | Tesis | S2 Teknik Sipil

Kerang merupakan binatang laut kelompok shellfish (bertempurung) yang mempunyai nilai gizi yang tinggi, lezat, gurih dan banyak digemari masyarakat. Kerang diperdagangkan ditempat–tempat seperti : pusat pelelangan ikan (PPI), pasar moderen (mall atau supermarket) maupun pasar tradisonal. Saat ini di pasar tradisonal Kobong Semarang terdapat dua jenis kerang yang diperdagangkan, yaitu jenis kerang yang terdapat dipinggir laut sekitar daerah pantai yang nama pasarannya disebut kerang darah dan jenis kerang yang terdapat agak ketengah lautan (kerang laut). Di pasar ini juga terdapat dua macam jenis perdagangan kerang, yaitu kerang yang dijual dengan isi (daging kerang) beserta cangkang/tempurungnya dan yang dijual hanya isinya saja tanpa cangkangnya. Cangkang kerang darah yang tidak diperdagangkan hanya ditumpuk dipengelolaan kerang atau dipinggir pantai dan belum dimanfaatkan secara maksimal. Penelitian ini menggunakan cangkang kerang darah yang tidak diperdagangkan tersebut sebagai agregat dalam pembuatan beton non pasir. Untuk pengujian kuat tekan dan kuat tarik belah benda uji dibuat masing–masing 3 buah dengan menggunakan variasi faktor air semen 0.3, 0.35, 0.4 dan variasi perbandingan volume semen/agregat 4, 6, 8 dan 10. Ukuran agregat cangkang kerang darah yang digunakan 10–20 mm, bentuk benda uji yang digunakan silinder ukuran diameter 150 mm dan tinggi 300 mm. Berdasarkan hasil pengujian diketahui semakin besar perbandingan volume semen : agregat dan semakin kecil faktor air semen yang dipergunakan, maka berat jenis, kuat tekan, kuat tarik belah dan modulus elastisitas beton non pasir yang didapat semakin rendah, tetapi volume rongga semakin tinggi. Sesuai dengan kuat tekan yang dihasilkan kemungkinan beton non pasir agregat cangkang kerang darah dapat dibuat bata beton Mutu III & Mutu IV.

Cockle represent animal go out to sea grouped in to shellfish having value of high nutrition, delicious, crispy and liked by the most of society. Cockle commercialized in the places of like : center of fish auction (PPI), modern market (mall or supermarket) and also traditional market. In this time in the traditional market Semarang, Kobong of there are two type of commercialized cockle, that is type of cockle which is exist at the near of sea and its commercial name is cookle of blood and type of cockle which is exist in the middle of the sea (sea cockle). In this market also there are two kinds of type of cockle commerce, that is cockle sold with the content (cockle flesh) and the shell and the cockle sold only just its contents without its shell. The shell of blood cockle which is uncommercialized is only heaped by the management of cockle or coastal periphery and have not been exploited yet maximally. This research used shell of blood cockle which is not commercialized as aggregate in making of the no fines concrete. For the compression and the split cylinder strength test made each 3 units by using variation of water/cement ratio 0.3, 0.35, 0.4 and variation of aggregate/cement ratio 4, 6, 8 and 10 by volume. The aggregate size of shell of blood cockle used was 10–20 mm, the form of the test object used was cylinder with the diameter 150 mm and with the lenght 300 mm. Based on the result of examination known that the greater of aggregate/cement ratio and the smaller of the water/cement ratio used, hence specific gravity, compression strength, split cylinder strength and modulus elasticity of no fines concrete which got progressively will be lower, but the volume of excelsior cavity will be higher. Appropriate to compression strength yielded gotten there is possibility that no fines concrete of aggregate shell of blood cockle can be made as brick of concrete Quality III & Quality IV.

Kata Kunci : Beton Non Pasir,Cangkang Kerang Darah,Agregat, shell of blood cockle, no fines concrete, water/cement ratio