Location
University of Leeds
Keywords
Self-compacting Concrete; Mineral additions; Durability; Permeability; acid attack
Abstract
Self-Compacting Concrete (SCC) can incorporate different types of Supplementary cementitious materials (SCM), as filler and other active mineral additions, to increase the amount of paste without increasing the amount of cement. SCM modify the SCC hardened microstructure due to the filler effect, the seeding effect as nucleation points for hydration products and the pozzolanic effect in the case of reactive SCM, as mineral additions (MA). The pore network is also modified which produce changes in the permeability of SCC. It is generally considered that the increase of fine particles improves SCC durability due to the larger compactness of the hardened material. However, MA also modifies the hydration process and consequently the hardened microstructure that could, in some cases, reduce the chemical resistance. Accordingly, the durability of SCC can also be modified by the use of MA due to the combination of permeability and chemical resistance, which mainly depends on the paste phase of the composite. When subjected to chemical attacks, SCC with MA would also modify the microstructure and the permeability properties in the long term. In order to evaluate the effect of different mineral additions, as limestone filler, microsilica, nanosilica and metakaolin, on SCC long term performance and assess their impact on its durability, an experimental study was carried out. Air and water permeability was measured on 5 years old samples SCC with different MA. It was seen that SCC air permeability was similar independently of the MA type and amount used. The samples were then subjected to acetic and sulfuric acid attacks. It was observed that the chemical resistance against acids depended on both permeability, the type of acid and the MA. The particle size and reactivity of the MA also contributed to the chemical resistance and therefore, to SCC durability.
Included in
Long Term Permeability and Acid Resistance of SelfCompacting Concretes with Micro and Nano Mineral Additions
University of Leeds
Self-Compacting Concrete (SCC) can incorporate different types of Supplementary cementitious materials (SCM), as filler and other active mineral additions, to increase the amount of paste without increasing the amount of cement. SCM modify the SCC hardened microstructure due to the filler effect, the seeding effect as nucleation points for hydration products and the pozzolanic effect in the case of reactive SCM, as mineral additions (MA). The pore network is also modified which produce changes in the permeability of SCC. It is generally considered that the increase of fine particles improves SCC durability due to the larger compactness of the hardened material. However, MA also modifies the hydration process and consequently the hardened microstructure that could, in some cases, reduce the chemical resistance. Accordingly, the durability of SCC can also be modified by the use of MA due to the combination of permeability and chemical resistance, which mainly depends on the paste phase of the composite. When subjected to chemical attacks, SCC with MA would also modify the microstructure and the permeability properties in the long term. In order to evaluate the effect of different mineral additions, as limestone filler, microsilica, nanosilica and metakaolin, on SCC long term performance and assess their impact on its durability, an experimental study was carried out. Air and water permeability was measured on 5 years old samples SCC with different MA. It was seen that SCC air permeability was similar independently of the MA type and amount used. The samples were then subjected to acetic and sulfuric acid attacks. It was observed that the chemical resistance against acids depended on both permeability, the type of acid and the MA. The particle size and reactivity of the MA also contributed to the chemical resistance and therefore, to SCC durability.
