Author
Highlights
Abstract
To transform construction wood waste by magnesia-phosphate cement (MPC) into cement-bonded particleboards, instability of MPC in water that compromises durability of particleboards in moist environment needs to be addressed. This study proposed a novel use of alumina and red mud to improve water resistance of MPC particleboards. Cement hydration chemistry and microstructure characteristics were revealed by quantitative X-ray diffraction analyses and scanning electron microscopy. Addition of alumina or red mud (Mg/Al or Mg/Fe at optimal molar ratio of 10:1) facilitated formation of amorphous Mg
Al or MgAlFe phosphate gel, respectively, which enhanced compressive strength. Alumina improved short-term water resistance, whereas red mud provided better long-term water resistance. Red mud-MPC binder enhanced strength retention (by 22.8%) and reduced water absorption (by 26.4%) of particleboards after 72-h water immersion, probably attributed to stable scaly-like MgAlFe phosphate gel. This study demonstrated that red mud and wood waste are sustainable materials for producing particleboards.
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http://www.sciencedirect.com/science/article/pii/S0959652617320310
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
- Received 6 June 2017, Revised 2 August 2017, Accepted 4 September 2017, Available online 7 September 2017
- https://doi.org/10.1016/j.jclepro.2017.09.038
Highlights
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- Addition of alumina and red mud enhanced the mechanical strength of MPC blocks.
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- Alumina-modified MPC blocks presented promising short-term water resistance.
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- Red mud promoted the long-term water resistance of MPC particleboards.
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- Red mud-modified MPC binder showed excellent compatibility with wood waste.
Abstract
To transform construction wood waste by magnesia-phosphate cement (MPC) into cement-bonded particleboards, instability of MPC in water that compromises durability of particleboards in moist environment needs to be addressed. This study proposed a novel use of alumina and red mud to improve water resistance of MPC particleboards. Cement hydration chemistry and microstructure characteristics were revealed by quantitative X-ray diffraction analyses and scanning electron microscopy. Addition of alumina or red mud (Mg/Al or Mg/Fe at optimal molar ratio of 10:1) facilitated formation of amorphous Mg
Al or MgAlFe phosphate gel, respectively, which enhanced compressive strength. Alumina improved short-term water resistance, whereas red mud provided better long-term water resistance. Red mud-MPC binder enhanced strength retention (by 22.8%) and reduced water absorption (by 26.4%) of particleboards after 72-h water immersion, probably attributed to stable scaly-like MgAlFe phosphate gel. This study demonstrated that red mud and wood waste are sustainable materials for producing particleboards.Graphical abstract
http://www.sciencedirect.com/science/article/pii/S0959652617320310
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