Sludge biochar as a green additive in cement-based composites: Mechanical properties and hydration kinetics

doi:10.1016/j.conbuildmat.2020.120723

	Sludge biochar as a green additive in cement-based composites: Mechanical properties and hydration kinetics
	Chen, Xin 1,2,3; Li, Jiangshan 1,3; Xue, Qiang 3; Huang, Xiao 3; Liu, Lei 1,3,4; Poon, Chi Sun 1,5
刊名	CONSTRUCTION AND BUILDING MATERIALS
	2020-11-30
卷号	262 页码:15
关键词	Municipal sludges biochar Cement-based composites Mechanical properties Hydration mechanisms Sustainable waste management
ISSN号	0950-0618
DOI	10.1016/j.conbuildmat.2020.120723
英文摘要	Biochar is a green material obtained from the thermochemical decomposition of biosolids under an anaerobic or oxygen-limited condition. Although sludge pyrolysis has been extensively studied in municipal sludge (MS) disposal, it is challenging to utilize the formed sludge biochar (SB) products. This study developed a novel and sustainable method for incorporating SB-derived biochar in cement-based composites, providing an economical and efficient way of recycling such wastes. A series of SB were prepared under different pyrolysis processes to replace 2% cement. Numerous mechanical, physical, microstructural and isothermal calorimetry analyses were used to study the performances of the SB incorporated cement composites. The results showed that the mobility of the composites declined slightly with the addition of SB. Pyrolysis regimes played a key role in influencing the strength, and the optimum performance was obtained at a pyrolysis regime of 500 degrees C and residual time of 60 min, which increased the 1 d and 28 d strengths by 29.3% and 5.8%, respectively. The addition of SB accelerated the formation of more hydration products, increased the hydration degree and led to a denser matrix. All these improvements were ascribed to the internal curing effect of sludge biochar and a decrease in the ratio of local water to cement. Thermal analysis by Krstulovic-Dabic Model indicated that the hydration mechanisms of biochar-cement composites belonged to nucleation and crystal growth (NG)- interactions at phase boundaries (I)-diffusion (D). The SB incorporated sample possessed more nucleation sites with a higher reaction rate constant at NG stage and shorter I stage. In addition, environmental risk assessment revealed that SB was a safe additive in cement-based composites. Therefore, pyrolysis of MS under appropriate temperature conditions has great potential to provide a green biochar in cement-based composites and thereby offers an alternative and viable way of disposal of MS. (C) 2020 Elsevier Ltd. All rights reserved.
资助项目	National Science Foundation for Distinguished Young Scholars[51625903] ; National Key Research and Development Programme[2019YFC1804002] ; National Natural Science Foundation of China[51861165104] ; Special Fund for Basic Research on Scientific Instruments of the National Natural Science Foundation of China[51827814] ; Foundation for Innovative Research Groups of Hubei Province[2019CFA012] ; Youth Innovation Promotion Association CAS[2017376]
WOS研究方向	Construction & Building Technology ; Engineering ; Materials Science
语种	英语
出版者	ELSEVIER SCI LTD
WOS记录号	WOS:000582531500153
内容类型	期刊论文
源URL	[http://119.78.100.198/handle/2S6PX9GI/25216]
专题	中科院武汉岩土力学所
通讯作者	Li, Jiangshan; Xue, Qiang
作者单位	1.Chinese Acad Sci, IRSM, HK PolyU Joint Lab Solid Waste Sci, Wuhan 430071, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn, Wuhan 430071, Peoples R China 4.Hubei Prov Key Lab Contaminated Sludge & Soil Sci, Wuhan 430071, Peoples R China 5.Hong Kong Polytech Univ, Dept Civil & Environm Engn, Kowloon, Hong Kong, Peoples R China
推荐引用方式 GB/T 7714	Chen, Xin,Li, Jiangshan,Xue, Qiang,et al. Sludge biochar as a green additive in cement-based composites: Mechanical properties and hydration kinetics[J]. CONSTRUCTION AND BUILDING MATERIALS,2020,262:15.
APA	Chen, Xin,Li, Jiangshan,Xue, Qiang,Huang, Xiao,Liu, Lei,&Poon, Chi Sun.(2020).Sludge biochar as a green additive in cement-based composites: Mechanical properties and hydration kinetics.CONSTRUCTION AND BUILDING MATERIALS,262,15.
MLA	Chen, Xin,et al."Sludge biochar as a green additive in cement-based composites: Mechanical properties and hydration kinetics".CONSTRUCTION AND BUILDING MATERIALS 262(2020):15.