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Banyak penelitian beton menggunakan substitusi material pengganti berupa abu terbang (fly ash) yang berasal dari abu sisa pembakaran batu bara dari Industri PLTU. Penggunaan batu bara juga dimanfaatkan industri pengolahan daun Dilem di PT. SCI di daerah Purbalingga. Untuk pemanfaatan limbah abu sisa pembakaran Industri Daun Dilem dilakukan penelitian tentang kuat tekan beton menggunakan abu sisa pembakaran batubara dari PT. SCI . Tujuan dari penelitian adalah mengetahui pengaruh penggunaan abu sisa pembakaran batu bara terhadap kuat tekan beton dan mengetahui selisih kuat tekan beton yang dihasilkan dengan prosentase abu sisa pembakaran batu bara 10%, 12,5%, 15%, dan 17,5% terhadap berat semen. Penggunaan abu sisa pembakaran batubara mempengaruhi kuat tekan beton yang dihasilkan, dengan prosentase abu sisa pembakaran batubara sebesar 12,5% sebagai substitusi semen memberikan kuat tekan beton paling maksimal sebesar 23,0 Mpa.Kata Kunci : Beton, Kuat tekan beton, Abu Terbang, Abu Sisa Pembakaran batu bara.

Construction project is a project that involved many parties and consist of various work items that must be executed. In most cases the executed work items has possibilities of danger and risk that threatening the worker's health and safety. This study was carried out using Job Safety Analysis on pile foundation work of a building and executed by direct interview and field observation. The result is that from 4 primary steps of pile foundation work there are indications of 10 dangers and 15 risks that may be experienced by the workers. Preventive and control measures can be carried out to anticipate the danger and risk potential by involving the stakeholders of pile foundation work execution.

Nowadays, concrete is still one of the most used building materials, it had been improved whether in it’s quality or it’s mixture materials. There were a lot of studies that had been conducted to improve concrete that related to the produced compressive strength, stiffening speed, flexibility, etc. There are so many materials that can be used in concrete mixture to improve compressive strength. This study was conducted by using superplasticizer and reducing water amount in concrete mixture and aimed to find out how big it’s effects on the produced concrete compressive strength. Superplasticizer was used as admixture material wtih 1 percentage calculated by cement weight. Whereas water amount in concrete mixture was reduced by 0%, 15%, and 17,5%. The result obtained was that using 1% superplasticizer and reducing 15% water amount in concrete mixture produced optimum compressive strength of 22,98 Mpa.

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