Durability of Ternary Cements Based on New Supplementary Cementitious Materials from Industrial Waste

• Published in: Applied sciences 2021-07, Vol.11 (13), p.5977
• Main Authors: Sáez del Bosque, Isabel Fuencisla, Sánchez de Rojas, María Isabel, Medina, Gabriel, Barcala, Sara, Medina, César
• Format: Article
• Language: English
• Subjects: Agroforestry; Bearing materials; Binders; Biomass; biomass ash; By products; Cement; Cement hydration; cement pastes; Cements; Chemical analysis; Concrete; construction and demolition waste; corrosion index; Decay; Demolition; Durability; Industrial wastes; Maintenance costs; Masonry; Mercury; Mineralogy; Porosity; Power plants; Reaction products; Scanning electron microscopy; Seawater; Silica; Silica fume; Sodium chloride; Sodium sulfate; supplementary cementitious materials; Ultrafines; Waste materials; Water analysis; X-ray diffraction
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app11135977

Cement-based materials decay with exposure to aggressive agents, a development that raises infrastructure operation and maintenance costs substantially. This paper analyses the inclusion of ultrafine construction and demolition (UC&DW) and biomass-fuelled power plant (BA) waste as pozzolanic additions to cement in pursuit of more sustainable and eco-respectful binders and assesses the durability of the end materials when exposed to seawater, chlorides (0.5 M NaCl) or sulphates (0.3 M Na2SO4). The effect of adding silica fume (SF) at a replacement ratio of 5% was also analysed. Durability was determined using the methodology proposed by Koch and Steinegger, whilst microstructural changes were monitored with mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy (SEM) for a fuller understanding of decay processes. According to the findings, the new blended cements containing 20%UC&DW + 10%BA or 20%UC&DW + 20%BA + 5%SF resist the attack by the aggressive media studied, with a 56-d corrosion index of over 0.7. The composition of the reaction products generated with the attack is essentially the same in OPC and the SCM-bearing materials. The results show that the optimal replacement ratio for SCM is 30%.