Study on Modification and Mechanism of Construction Waste to Solidified Silt

• Published in: Materials Vol. 16; no. 7; p. 2780
• Main Authors: Shi, Yannan, Weng, Haoxuan, Yu, Jiongqi, Gong, Yongfan
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30.03.2023; MDPI
• Subjects: Cement; Compression tests; Construction; Construction materials; Curing; curing agent; Curing agents; dredged sediment; Environmental protection; Fly ash; Laws, regulations and rules; Mechanical properties; mechanism analysis; Moisture content; Morphology; Particle size; Permeability; Permeability tests; Pore size; Research methodology; Rivers; Sand; Scanning electron microscopy; Silicon compounds; Silt; skeleton structure; Sludge; Sodium hydroxide; Sodium silicates; Soil compaction; Soil improvement; Soil lime; Soil permeability; Soil stability; Soil stabilization; Soils; Solidification; stability; Triethanolamine; Waste disposal; Water stability; dredged sediment; curing agent; mechanism analysis; skeleton structure; stability
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16072780

A large amount of silt may be produced in river and lake regulation. It not only occupies land but also pollutes the environment. Therefore, it is urgent to seek effective disposal and utilization methods. Based on the problems of poor stability of stabilized soil and its tendency to soften easily in water, as well as its low strength with low curing agent dosage, this paper proposes a method to improve stabilized soil's solidification effect by adding materials such as cement, lime, fly ash, triethanolamine, sodium hydroxide, sodium silicate, etc., while mixing different grain diameters and quantities of building waste materials and ordinary sand. Using construction waste and ordinary sand as a comparative test, the curing mechanism of construction waste debris on the mechanical properties, permeability, and microstructure of solidified sludge was studied through unconfined compression tests, dry and wet cycle tests, permeability tests, and micro-structure tests such as XRD, MIP, and SEM. The test results show that the strength increases 8.5%~72.1% by adding building waste materials, and it grew with the increase in particle size and amount. It reduced the content of large pore size of solidified sediment and optimized the internal pore structure. At the same time, it formed a new structure filled by rigid skeleton material. Thus, it improved its unit section stress, built up the curing effect and water stability. The findings of this study can be used to modify solidified silt to improve stability and compaction characteristics.