• Kaare Hedegaard
4. term, Structural and Civil Engineering, Master (Master Programme)
This report deals with the study of silica fumes proporties in High Performance Concrete (HPC), where the objective is to optimize the use of this material so that a more compact and stronger concrete is created. It is derived from theoretical calculations that the best ratio between cement and silica fume is 80%/20%. By using this ratio the highest degree of packing is achieved and thereby a more compact concrete is achieved. Subsequently these materials are used in experiments performed on morters. The experiments are about the rheological properties, strenght and sorptivity of HPC-morters by the use of different types of cement, silica fumes and high range water reducers. The results show that the high range water reducer Betanaphtalensulfornat (BNS) and rapid cement do not work together and the high range water reducer Polycarboxyleter (PCE) with long side chains and high strength do not work in a HPC-morter. It is also found that silica fume's specific surface is crucial for HPC's casting abillity. This is documented by comparison of three different silica fumes with different specific surfaces. Moreover the strength is found for the best HPC-morters and a result of 100MPa after hardning in seven days is obtained. Finally a sorptivitytest is performed and the results show a sorptivity of 0,11 g/m2 s½ as the lowest.
Publication date2009
Number of pages102
Publishing institutionAalborg Universitet, Institut for Byggeri og Anlæg
ID: 17696465