Optimal design and performance of eco-friendly materials stabilized with inorganic binder based on fluidized bed coal combustion fly ash and regenerated brick powder

Abstract

The development of green and eco-friendly road engineering materials has become essential to achieving carbon emission reduction and sustainable development. In this study, recycled brick powder (RBP) from construction waste and fluidized bed coal combustion fly ash (FBCF) are combined to replace the traditional lime-fly ash diatomic material in order to produce eco-friendly materials stabilized with inorganic binder (EFMSIB) for roads. The results showed that, when the ratio of EFMSIB is m(RBP):m(FBCF):m(Aggregate) equals 7%:13%:80%, its 7d and 28d unconfined compressive strength are 3.4 MPa and 8.72 MPa, respectively, 180d compression rebound modulus is 1440 MPa, 180d bending tensile strength is 1.51 MPa, 28d mass loss rate is 1.87%, and the residual compressive strength was 93.36%, and all the properties reached the optimal values. The composite material of FBCF and RBP can complete the pozzolanic reaction to form ettringite (AFt) relatively quickly at the early stage of hydration, which promotes the development of the early strength of hydration products, resulting in the compressive strength of NT4 increased by 1.8 times compared with the reference sample. With the growth of the curing age, the active SiO2 and Al2O3 in the material react with CaO to produce hydrated calcium silicate, which promotes the development of the strength of the system in the later stage, resulting in the compressive strength of NT4 increased by 1.6 times compared with the reference sample. The prepared EFMSIB material has a better self-consolidation effect on heavy metals, and the leachate heavy metal ion concentration of NT4 can reach the standard of class III surface water.