Beton merupakan bahan yang paling penting dan paling banyak digunakan dalam dunia konstruksi, baik berupa gedung, jembatan, maupun jalan. Campuran beton terdiri dari semen, pasir, kerikil, air dan bahan tambah lainnya dengan perbandingan tertentu. Pada penelitian ini pembuatan beton menggunakan limbah abu terbang (fly ash) cangkang kelapa sawit sebagai pengganti sebagian semen, dan penambahan additive admixture yaitu superplasticizer. Bahan tambah ini bertujuan untuk mengetahui sejauh mana pengaruh penggantian semen dengan abu terbang (fly ash) cangkang kelapa sawit dan superplasticizer terhadap kuat tekan beton, kuat tarik belah beton dan absopsi beton. Komposisi penggantian semen dengan abu terbang (fly ash) cangkang kelapa sawit sebanyak 0%, 5%, 10% dan 15% dari berat semen, dan superplasticizer sebanyak 2%. Pengujian kuat tekan dilakukan pada umur beton 7 hari, 14 hari, dan 28 hari, sedangkan kuat tarik dan absorpsi dilakukan pada saat umur 28 hari. Dari penelitian diperoleh bahwa kuat tekan beton yang tertinggi terdapat pada campuran beton dengan Fly Ash 10% + superplasticizer 2% yaitu sebesar 33,404 MPa dan dari hasil pengujian kuat tarik belah yang tertinggi pada campuran beton dengan Fly Ash 10% + superplasticizer 2% yaitu sebesar 3,348 MPa sedangkan hasil pengujian absorpsi tertinggi terdapat pada beton normal sebesar 1,85%.

Concrete is the most important and most widely used material in the construction world, in the form of buildings, bridges and roads. Concrete mixture consisting of cement, sand, gravel, water and other added ingredients with a certain ratio. In this study the manufacture of concrete using palm ash shell fly ash as a partial replacement for cement, and the addition of additive admixture, namely superplasticizer. This added material aims to determine the extent of the effect of cement replacement with palm oil fly ash and superplasticizer on the compressive strength of concrete, the tensile strength of concrete and absorptive concrete. The composition of cement replacement with oil palm fly ash is 0%, 5%, 10% and 15% by weight of cement, and superplasticizer is 2%. Compressive strength testing is performed at the age of concrete 7 days, 14 days and 28 days, while the tensile and absorption strength is carried out at the age of 28 days. From the research it was found that the highest compressive strength of concrete was found in concrete mix with Fly Ash 10% + superplasticizer 2% which was 33,404 MPa and from the results of the test of the highest tensile strength in concrete mix with Fly Ash 10% + 2% superplasticizer that was 3,348 MPa while the highest absorption test results are found in normal concrete at 1.85%.