Hydration–Pore Architecture Regulation and Multifunctional Performance of a Quaternary Solid-Waste-Based Lightweight Porous Cementitious Material

Abstract

Lightweight, thermally insulating, and electromagnetic wave-absorbing building materials were developed using a quaternary solid-waste-based cementitious system composed of steel slag, blast furnace slag, phosphogypsum, and copper slag. The effects of Li₂CO₃, hydroxypropyl methylcellulose (HPMC), and calcium stearate (CS) on hydration behavior and pore-structure evolution were systematically investigated. Li₂CO₃ accelerated hydration and enhanced strength, whereas HPMC refined pore architecture and reduced thermal conductivity (minimum 0.0488 W m⁻¹ K⁻¹), and CS increased closed porosity and water resistance. Coordinated regulation of hydration kinetics and pore structure led to enhanced electromagnetic attenuation dominated by dielectric loss with magnetic-loss assistance, achieving a minimum reflection loss of −67.02 dB at 10.20 GHz (2.78 mm). Life-cycle assessment confirmed superior sustainability compared with OPC-based foamed concrete.