## 1 Introduction  
The persistent escalation of human-generated CO\({}_{2}\) emissions continues to aggravate global warming patterns. The construction industry has become a principal CO\({}_{2}\) emission source worldwide [1], attributable to its resource-heavy operations and energy-intensive production systems. This environmental urgency has intensified international initiatives to optimize buildings' energy performance and implement sustainable construction methodologies as climate resilience measures. International Energy Agency (IEA) records show that 2022 global CO\({}_{2}\) emissions totaled 37 gigatons, where China accounted for 30% as the predominant emission source [2]. The Chinese government has instituted dual carbon commitments (carbon peaking by 2030 and carbon neutrality by 2060) as national climate strategies [3]. Multisectoral cooperation is imperative for target fulfillment, where the building sector's substantial emissions profile presents critical carbon reduction opportunities. A provincial-level study by Xian [4] systematically analyzed direct (DCEs), indirect (ICEs), and total carbon emissions (TCEs) in China's CI spanning 2005-2021. The research uncovered an extreme emission imbalance, with ICE--defined as CI-triggered CO\({}_{2}\) discharge emissions (CDEs)--persistently constituting >90% of total emissions, revealing construction CDEs to be predominantly derived from material manufacturing sectors (timber, cement, steel) (Figure 1). Substantiating this finding, China's 2020 building lifecycle emission analysis documented 5.08 billion tons of total CO\({}_{2}\), with material production contributing 2.82 billion tons (28.2% of national emissions), creating significant obstacles for dual carbon target achievement [5]. These insights confirm that material decarbonization constitutes a pivotal research frontier for sustainable construction development. Traditional concrete creates significant carbon footprints during manufacturing and application phases, coupled with inefficient energy utilization and inadequate thermal insulation performance. Foam concrete (FC) has been developed as an innovative eco-friendly construction material, where controlled foam integration into cementitious matrices creates a dense closed-cell porosity, effectively decreasing cement consumption and associated carbon emissions during building processes [6]. FC exhibits a density range of 400-1850 kg/m\({}^{3}\) and superior strength-to-weight ratio compared to ordinary concrete [7; 8], enabling reduced dead loads of structural components and lower fabrication, transportation, and on-site labor expenditures [9]. The engineered void network significantly upgrades thermal regulation, sound attenuation, and fire resistance of monolithic concrete, with its honey  
Figure 1: Percentage of CDE types in China’s construction industry and annual growth rate. comb morphology providing exceptional thermal insulation adaptability across climatic zones [10; 11]. Steel slag (SS), a by-product of steel manufacturing processes, constitutes 15-20% of crude steel output by mass [12]. In 2021, China produced 1.035 billion tons of crude steel [13], representing > 50% of global production (1.9505 billion tons) [14], resulting in an SS output exceeding 120 million tons. Comparatively, developed nations maintain > 90% SS recycling efficiencies, while China's utilization stagnates at ~20% [15]. Approximately 80% of SS is disposed via landfilling/open storage, occupying extensive land areas. Moreover, SS harbors multiple heavy metal constituents that are capable of migrating through leaching processes to surrounding ecosystems, threatening ecological integrity and public health [16]. Additionally, inadequate SS handling during storage/transport releases airborne particulates, exacerbating atmospheric pollution and respiratory hazards in proximate communities.