No abstract

Block made of mud is a building material used in making wall for building that is made fromsand, cement, and fly ash using certain percentage mud in sand. This research aimed to know theeffect of the use of lapindo mud towards the compressive strength, the absorption of block waterwith the mud dosage in sand are: 0%, 10%, 20%, 30%, and 40%. This research was an experimentalresearch; each design was made in size 10x20x40 cm using 5% of fly ash and without fly ash.The result of this research showed that the highest compressive strength was raised in 10%mud in sand with 5% fly ash that was 195 kg/cm2 or increased about 3.44 kg/cm2 within increasingpercentage about 10.651% towards the compressive of block without lapindo mud with 5% of flyash, and was included in class I quality of block. While for the 30% and 40% mud percentage islower compared with normal compressive strength of block. The test result of water absorption oflapindo mud block showed the higher value than 20% for lapindo mud block with 5% fly ash, inframing the mud blocks as the wall, those blocks need to be soaked first because the absorptionvalue of block is higher than 20%. Lapindo mud block without 5% fly ash has bricks water absorptionless than 20%, while in framing those bricks, they don’t need to be soaked because the absorptionof brick if lower than 20%. By using fly ash in mud block, we can get the higher compressivestrength and the lower water absorption.Keyword: Porong Mud, Block, Fly Ash, Compressive Strength, Absorption

PENGARUH BOTTOM ASH SEBAGAI PENGGANTI PASIR DANLIMBAH KARBIT SEBAGAI BAHAN TAMBAH SEMENTERHADAP BERAT JENIS, KUAT TEKAN, DAN ABSORBSIBATAKONur Ali1, Rofikatul Karimah2 , H. E.Meiyanto31,2,3 Jurusan Teknik Sipil Fakultas Teknik – Universitas Muhammadiyah MalangAlamat korespondensi : Jalan Raya Tlogomas 246 Malang 65144Email: rofikatulkarimah@gmail.comABSTRACTBasically concrete brick is formed from cement, sand and water, than a breakthroughmade in manufacturing of concrete brick with the utilization of wastes which have no economicvalue are also widely available in the environment than is waste of bottom ash an carbide. In thisresearch, a normal concrete brick consist of cement, san, and water which given variation ofcarbide waste ranging from 10%, 20%, and 30%, afterwards a replacement of sand by bottomash is made with a given variation of carbide waste 10%, 20%, and 30%. Result of the researchthat applying sand as subtle aggregate and waste of carbide as additional material for cementgets the best result on the variation of carbide waste 30% with strength of compression 69,10MPa and 3,58% absorption capacity, it is better rather than normal concrete brick on the variationof carbide waste 0% with compressive strength of 48,74 MPa and 5,49 absorption capacity.After wards, by doing replacement of sand with bottom ash as subtle aggregate and addedwaste carbideas its variations is obtained the best results in the variation of carbide waste 30%with compressive strength 52,37 MPa and 6,92 of absorption capacity better rather than 0% ofvariation carbide waste with strength of compession 19,64 MPa and 12,01 of absorption capacity.Keyword: Concrete Brick, bottom ash, waste carbide.

Sejumlah penelitian teknologi kontruksi terus dikembangkan dengan tujuan dapat menghasilkan teknologi kontruksi yang tepat guna. Salah satunya dengan memanfaatkan serbuk kulit kerang yang dihasilkan oleh 89 unit pengolahan kerang di Desa Campurejo, Gresik. Dari 1 unit pengelolahan kerang mampu memanen ±100 kg setiap minggunya. Dari kegiatan tersebut dapat menghasilkan limbah padat berupa serbuk kulit kerang yang cukup tinggi. Untuk mengurangi dampak lingkungan dan kesehatan yang disebabkan oleh limbah tersebut, maka dilakukan pemanfaatan limbah serbuk kulit kerang sebagai bahan pengganti agregat halus pada campuran beton. Penelitian ini dilakukan untuk mengetahui pengaruh penggunaan serbuk kulit kerang sebagai pengganti agregat halus terhadap kuat tekan beton. Variasi penggunaan serbuk yang digunakan sebesar 0%, 5%, 10%, 15%, 20%, 25%, dan 30% dari berat agregat halus dengan FAS 0,6. Hasil pengujian diperoleh nilai kuat tekan beton mengalami kenaikan pada prosentase 10% dan selanjutnya kuat tekan beton menurun seiring dengan pertambahan prosentase penggunaan serbuk kulit kerang. Sedangkan nilai absorbsi beton mengalami kenaikan pada prosentase 30% dari berat agregat halus.

Foam concrete is an alternative wall material that can be used in tropical buildings because of its insulation properties, good thermal conductivity, and sound absorption coefficient when compared with the normal concrete. The percentage of foam agent used in its production affects density and compressive strength. Furthermore, the use of fly-ash also has an effect on its mechanical and insulation properties. In this study, 40 units of foam concrete specimen (200x200x20) mm were tested for thermal conductivity, and cylinder (dia-100x20) mm for sound absorption. The mixture used for the concrete includes cement/sand ratio of 1:2.75 with w/c 0.425 and addition of 20% fly-ash as a cementitious material and foaming agent (ratio fa/w 1:20) at 1%, 2%, 3% and 4% by weight of cement paste, respectively. The result showed that foam concrete with 20% fly-ash and 2% foaming agent or more has a density below 2000 kg/m3 with a maximum compressive strength of 13.24 MPa. The highest sound absorption coefficient was obtained to be a = 0.89 at 20% fly-ash and 4% foaming agent. The thermal conductivity (k) of foam concrete was found to have increased using a 20% fly-ash and 1% foaming agent compared to the mixture without fly-ash at a value of 0,898. It was discovered that the use of fly-ash on foam concrete has the ability to improve thermal conductivity and sound absorption.