Pembuatan dan Karakterisasi Beton Kedap Suara dari Serat Tandan Kosong Kelapa Sawit Semen PC dan Pasir

Abstract

The hollow bunch fiber of oil palm mixed with cement (PC) and sand can be used as a fiber concrete material. The fiber concrete that have been produced can be used as a relatively light-weight building material and can absorb the sound. The process making of the hollow bunch fiber of oil palm is washed with NaOH solution for 12 hours, dried and cut with a length of 20 cm. The fiber variation of 0, 2, 4, 6, 8, 10% (volume) was mixed with 350 gram of cement, 700 gram of particulate and aggregate sand and 500 ml of water. The analysis of weight loss, mechanical and physical properties, morphology and sound absorption are conducted at aging time of 28 days. The result shows that the fiber concrete with an optimum condition is achieved at 6% (volume) of oil palm hollow bunch fiber. The optimum condition of fiber concrete are resulting the value of weight loss = 8,5 %, bulk density = 2,4 g/cm3, water absorption = 13%, Modulus of Rupture (MOR) = 2,95 MPa, Compressive strength (CS) = 4,85 MPa and Modulus of elasticity (MOE) = 3,33 GPa. The morphology of concrete fiber that have been analyzed by using an optical microscope show that the pores have size less than 30μm and the concrete particle compound have size within a range of 5-30μm and the distribution of oil palm hollow bunch fiber is homogenous with size less than 75μm. The ability of the sound absorption on oil palm hollow bunch fiber concrete within a frequency range of 100 – 500 Hz are resulting sound intensity level of 58-90 dB, sound absorption of 19,82% and absorption coefficient (αaverage) of 0,026. The fiber concrete with 6% (volume) addition of oil palm hollow bunch fiber can be classified as light-weight and normal concrete and fulfill the criteria of sound absorber building material.

Serat tandan kosong kelapa sawit dicampur semen (Portland Cement) dan pasir dapat dibuat sebagai bahan beton serat. Beton serat yang dihasilkan bisa digunakan sebagai bahan bangunan relatif ringan dan mampu meredam suara. Proses pengolahan tandan kosong kelapa sawit dibilas dengan larutan 10% NaOH selama 12 jam, dikeringkan dan dipotong-potong sepanjang 5,0 cm. Variasi serat dibuat 0, 2, 4, 6, 8, 10 % (volum), dicampur semen 350 gram, pasir halus dan kasar masing-masing sebanyak 700 gram serta air sebanyak 500 ml. Pengamatan susut massa dilakukan pada saat proses aging (28 hari), pengujian sifat fisis dan mekanik, morfologi dan peredaman terhadap suara. Hasil pengamatan menunjukkan bahwa beton serat menghasilkan kondisi optimum pada 6 % (volum) serat tandan kosong kelapa sawit. Kondisi beton serat yang optimum menghasilkan nilai susut massa = 8,5 %, rapat massa = 2,4 g/cm3, penyerapan air= 13 %, Kuat bending beton = 2,95 MPa, kuat tekan beton = 4,85 MPa, dan Modulus elastis beton = 3,33 GPa.Morfologi beton serat yang diamati dengan mikroskop optik memperlihatkan adanya rongga-rongga yang berukuran lebih kecil dari 30 μm dan partikel pembentuk beton berkisar antara 5 – 30 μm dan distribusi serat tandan kosong kelapa sawit cukup merata yang berukuran lebih kecil dari 75 μm. Kemampuan daya redam suara beton serat pada daerah rentang frekuensi 100 – 5000 Hz menghasilkan intensitas sound level sekitar 58 – 90 dB, peredaman suara 19,82 % dan koefisien absorbsi (α rata-rata) sebesar 0,026. Beton serat dengan penambahan serat tandan kelapa sawit sebanyak 6 % (volum) termasuk klasifikasi beton ringan –normal dan memenuhi syarat sebagai material bangunan peredam suara.