Hydrothermal mineralization enabled upgrading reuse of construction-generated sludge waste for sustainable building material production

Abstract

This work reports an upgrading reuse of construction-generated sludge waste (CGSM) to manufacture value-added building materials using hydrothermal mineralization (HM). The optimization of mixture proportions and the influential factors of curing temperature and duration were explored. Results showed that high-strength HM-CGSW blocks over 50 MPa with a strength-to-calcium ratio of 2.95 MPa/percentage can be produced under an optimal Ca/Si ratio of 0.5 and HM curing of 200 °C for 12 h. The production of HM-CGSW block would generate 305.81 kg e-CO2/m3 and cost of 222.44 CNY/m3, lower than those of concrete block and autoclaved fly-ash block. An industrial application of HM-CGSW was proposed for upgrading use of CGSW to produce building materials for new constructions. The findings in this study would not only deepen the mechanistic understandings of HM treatment of sludge waste, but also shed much light on developing an industrial path that enables sustainable building material production.

Keywords

• Hydrothermal mineralization
• Strength
• Microstructure
• CO2 emissions