This research studied the effect of nickel-based cement substitution in concrete to analyze its behavior. The percentage of substituted nickel-slag was 10%, 20% and 30% to the cement weight. The mechanical properties studied were the compression f'c and tensile fMR stresses at the ages of 14, 28, 42 and 56 days. The data were analyzed and the visual observation of the fractured plans were addressed to determine the failure modes. The research concluded that the nickel-slag cement reduced both the compressive and tensile strength as a function of the substituted content, the decrease process followed a linear path. It was found that the strength of nickel-slag concrete cannot be defined at 28 days due to a prolonged chemical process.

Era kini ditandai dengan penekanan pada konsevasi energi, beton ramah lingkungan dan beton hijau. Semen merupakan bahan utama pembentuk beton, dan juga penyumbang pencemaran udara terbesar di antara bahan penyusun material tersebut. Semen slag atau Ground Granulated Blast Furnace Slag (GGBFS) yang merupakan hasil pengolahan limbah industri baja menjadi salah satu alternatif yang diminati karena proses produksi dan lebih ekonomis bila dibandingkan dengan Portland Cement (PC). Material yang mempunyai sifat cementitious ini berpotensi untuk menggantikan sebagian semen dalam campuran beton dengan tetap mempertahankan kelebihan sifat mekanis beton. Penelitian ini dilakukan di laboratorium dengan pengujian benda uji yang telah didesain dengan komposisi substitusi semen slag sebesar 0%, 10%, 20%, 30%, 40%, dan 50% dari berat semen yang dibutuhkan dan pada umur 28 hari. Sebagai benda uji kontrol beton direncanakan dengan kuat tekan f’c = 38 MPa. Semen slag yang digunakan berdasarkan referensi memiliki activity index grade 80. Penelitian dilakukan untuk mengetahui kinerja semen slag pada beton melalui pengamatan kuat tekan (f’c), hubungan tegangan-regangan (fc - ε) dan modulus elastisitas (E) beton. Pengujian menunjukkan bahwa substitusi slag menyebabkan terjadinya penurunan kuat tekan beton, regangan dan modulus elastisitas pada umur 28 hari karena adanya proses kimia yang lebih lamban daripada PC.

The use of industrial waste as a component of nowadays building material has become of major importance due to the underlining of environmental and sustainability issues. Among these materials is Ground Granulated Blast Furnace Slag (GGBFS), often referred to as slag-cement. The material is a residue produced during the steel refining process. The cementitious nature of the product makes it most suitable for ordinary Portland cement (PC) substitution. However, the behavior of this slag-cement in terms of development time and strength has not been defined in great details. In the construction industry, time is of major importance, a prolonged hydration process could delay the overall process. This research work focused on the setting time and strength response of slag-cement in mortar. The ratio of mortar constituent of cement-to-sand was 1 : 3. The percentage of slag-cement substitute to PC was 0%, 25%, 50% and 75% to the cement weight. The compressive strength was tested at the age of 14 days and 28 days. The results of the analysis showed that at a 25% slag-cement substitution a very significant increase in strength was shown. The increase was more pronounced at the age of 28 days when compared to 14 days and recorded to be 31.90%. As for the 50% and 75% slag-cement substitution, no significant increase in strength improvement was noticed. The test results showed a 2.66% enhancement for the 50% slag- cement substitution and a 2.45% increase for a 75% slag-cement replacement. The study also showed that slag-cement required a higher water-cement factor for the normal consistency