The conventional concrete which made with normal aggregates should be able to fullfill the improving of concrete technology where the high strength concrete was needed to support the load in order to minimize the building cost. Theomac SF 100-MB-SF admictures in the form of mineral material that have a high silica content and fineness of a aggregates. Rheobuild 1000 admixtures is one type of superplasticizer and will act as water reducing agent and minimizing water cement ratio. Combination of the two admixtures would give one alternative solution in order to get a high strength concrete. The research was run by making cylinder specimens and tested in 28 day age. The parameters of the research were water cement ratio and content of Rheomac SF 100-MB-SF and Rheobuild 1000. The results showed that the specimens which made with the addition of Rheomac SF 100-MB-SF and Rheobuild 1000 have very high compressive strength. By using water cement ratio of 3.0, the addition of Rheomac SF 100-MB-SF of 0%, 5%, 10% and 15% gave compressive strength of 65.135 MPa, 66.56 MPa, 81.74 MPa, and 95.698 MPa respectivelly, and 80.541 MPa, 84.059 MPa, 86.883 MPa and 85.427 MPa for water cement ratio of 3.50.Sudarmoko
