Properties and microstructure of eco-cement produced from co-sintered washed fly ash and waste sludge

• Published in: Environmental progress & sustainable energy Vol. 35; no. 3; pp. 764 - 771
• Main Authors: Lin, Kae-Long, Lo, Kang-Wei, Shie, Je-Lueng, Le Anh Tuan, Bui, Hwang, Chao-Lung, Chang, Yu-Min
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 01.05.2016
• Subjects: clinker; compressive strength; degree of hydration; recycling
• ISSN: 1944-7442; 1944-7450
• DOI: 10.1002/ep.12310

This study investigated the possibility of recycling washed fly ash, limestone sludge, stone sludge, and iron‐oxide sludge in raw meal for producing Portland cement clinker. All of the major phase components of ordinary Portland cement (OPC)—C3S, C2S, C3A, and C4AF—were identified in each eco‐cement clinker. The compressive strength development showed that the eco‐cement pastes no contained washed fly ash was similar to commercial OPC products. The exothermic peak at 105°C to 440°C corresponded to the coordination change of C‐S‐H gel in the pastes during curing time. The TG/DTA curves showed that the weight loss of the eco‐cement pastes no contained washed fly ash was higher than that of the eco‐cement pastes contained 1% washed fly ash. The Q0 (−70 ppm) species shifted to the Q1 (−80 ppm) and Q2 (−87 ppm) species during curing time. The degrees of hydration of the eco‐cement pastes contained 2 to 4% washed fly ash were lower than that of the eco‐cement pastes no contained washed fly ash. The results of the physicomechanical tests showed that adding the limestone sludge, stone sludge, and iron‐oxide sludge did not negatively affect the quality of the produced cement. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 764–771, 2016