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

Abstract

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%.

Utilization of Sugar Mill Waste Ash as Pozzolanic Material in Structural Mortar

“…It has been demonstrated that concrete containing mineral admixtures is significantly more resistant to chlorides and other agents that cause degradation [14,21]. To a large extent, it is influenced by a small number of criteria, including the manner in which the minerals react with the oxides during the hydration stage, the nature of the chlorides and the effects that they have [16,58,60]. As a consequence of these factors, the strength of mortar that contains BA can be affected negatively if it is exposed to a chloride environment.…”