TY - CONF A1 - Quercia, G. A1 - Spiesz, P. A1 - Hüsken, Götz A1 - Brouwers, H.J.H. T1 - Chloride intrusion and freeze-thaw resistance of self-compacting concrete with two different nano-SiO2 T2 - 18. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2012-09-12 KW - Nano-SiO2 KW - Concrete KW - Self compacting KW - Durability KW - Chloride and freeze-thaw KW - Nano-silica PY - 2012 SN - 978-3-00-034075-8 VL - 2 IS - 3.07 SP - 2-0123 - 2-0136 AN - OPUS4-26542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Quercia, G. A1 - Spiesz, P. A1 - Hüsken, Götz A1 - Brouwers, H.J.H. T1 - SCC modification by use of amorphous nano-silica N2 - In this study two different types of nano-silica (nS) were applied in self-compacting concrete (SCC), both having similar particle size distributions (PSD), but produced through two different processes: fumed powder silica and precipitated silica in colloidal suspension. The influence of nano-silica on SCC was investigated with respect to the properties of concrete in fresh (workability) and hardened state (mechanical properties and durability). Additionally, the densification of the microstructure of the hardened concrete was verified by SEM and EDS analyses. The obtained results demonstrate that nano-silica efficiently used in SCC can improve its mechanical properties and durability. Considering the reactivity of the two applied nano-silicas, the colloidal type showed a higher reactivity at early age, which influenced the final SCC properties. KW - Nano-silica KW - Self compacting concrete KW - Durability KW - Chloride KW - Freeze-thaw PY - 2014 U6 - https://doi.org/10.1016/j.cemconcomp.2013.09.001 SN - 0958-9465 SN - 1873-393X VL - 45 SP - 69 EP - 81 PB - Elsevier CY - Barking, Essex AN - OPUS4-30385 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quercia, G. A1 - Hüsken, Götz A1 - Brouwers, H.J.H. T1 - Effect of olivine nano-silica additions on the fresh and hardened behaviour of cement pastes and mortars N2 - The high demand for sustainable and durable building materials requires profound knowledge on the material properties. In this respect, the phenomena occurring at nano-level are of crucial importance for the design of new building materials. Therefore, all around the world, increasing amounts of funding are being directed to research projects dealing with material properties on nano-level, which is claimed to have tremendous potential for the future. One of the most referred to and used cementitious nano-material is amorphous silica with a particle size in the nano-range, even though its application and effects on concrete have not been fully understood yet. Olivine (Mg,Fe)2Si04 is the fastest weathering siiicate mineral dissolving easily in acid. Düring dissolution in acid the metallic ions (Mg2+,Fe2+) are replaced by H+, yielding Si(OH)4 monomers and metallic ions in solution. After cleaning treatments an amorphous nano-silica is obtained. The produced olivine nano-silica (OnS) has a specific surface area between 100 and 400 m2/g, the size of the primary particles, which are agglomerated in Clusters, ranges from 10 to 25 nm and the impurity content is below 5 % IV. Literature related with the application of OnS in cement based materials is scarce; only one research work performed by Justnes and Ostnor 121 is available. Thus, the effect of adding OnS in cement based Systems has been not studied. Based on this, the present research aims on elucidating the effects of OnS in the fresh and hardened state of cement pastes and mortars. T2 - 1st International conference on the chemistry of construction materials CY - Berlin, Germany DA - 07.10.2013 KW - Nano-silica KW - Self compacting concrete KW - Durability KW - Chloride KW - Freeze-thaw PY - 2013 SN - 978-3-936028-75-1 SP - 179 EP - 182 AN - OPUS4-30410 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -