Improvement of fracture toughness of green concrete as a result of addition of coal fly ash. Characterization of fly ash microstructure

摘要: Abstract Composites with the addition of coal fly ash (CFA) can be included in sustainable and green concrete. Effective promotion concrete incorporating CFA is necessary to minimize threat environment posed by waste disposal reduce cement consumption thus cutting CO2 emissions. This study investigates influence curing time on fracture toughness produced different concentrations CFA. Concentrations 20% – CFA-20 30% CFA-30 were used results compared a reference mixture 100% Ordinary Portland Cement (OPC) CFA-00. Compressive strength fcm under mode I KIcS (tension at bending), determined after: 3, 7, 28, 90, 180 365 days. The obtained lead conclusion that, it possible make containing high toughness. Furthermore, this one ways industry additive guarantees mature concretes, whereas characterized highest dynamic increase parameter KIcS. experimental program was completed analysis microstructure using SEM. These studies showed that main morphological forms are single grains, such as: pyrospheres, cenospheres, plerospheres, multispheres, ferrospheres, grains irregular shapes, amorphous grains. Grains may also occur larger quantities, jointed clusters agglomerates.