Decarbonization policies in the construction and building sector have spurred the search for materials with a lower environmental impact. Traditional techniques, such as earth-based materials (EBMs), have inspired innovative solutions, although these materials often need enhancement to meet modern performance demands. Typically, this requires reinforcement or stabilization, which can increase both the carbon footprint and manufacturing costs. This study explores the feasibility of using powdered waste from concrete recycling (hydrated cement powder, HCP), which currently lacks effective utilization pathways. HCP, consisting mainly of hydrated cement and fines, has potential cementitious properties. We investigated the impact of incorporating HCP into EBMs by replacing soil with HCP at proportions of 20 %, 25 %, 30 %, 35 %, 40 %, and 60 %. The evaluation included tests for shrinkage, density, compression and flexural strength, thermal properties (thermal conductivity and specific heat capacity), and resistance to water (Swinburne's accelerated erosion test). Additionally, the microstructure of both the raw materials and the resulting EBMs was analyzed through the particle size distribution, scanning electron microscopy, X-ray diffraction, and X-ray fluorescence. The results show that HCP improves thermal resistance (e.g., from 0.86 to 0.4 W m⁻1 K⁻1 with 60 % HCP) while slightly reducing thermal capacity by approximately 30 %. Rainwater erosion is effectively mitigated from 35 % HCP. However, increased porosity from HCP leads to reduced compressive and flexural strength (e.g., from 3.4 to 1.5 MPa and from 1.2 to 0.5 MPa, respectively, with 60 % HCP). In conclusion, incorporating 35 % HCP is technically feasible, producing a lighter block with enhanced thermal resistance while meeting EN41410 standards.

中文翻译：

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通过添加来自再生混凝土的水化水泥粉来稳定挤压土基材料


建筑业的脱碳政策刺激了对环境影响较小的材料的寻找。土基材料 （EBM） 等传统技术激发了创新解决方案的灵感，尽管这些材料通常需要改进才能满足现代性能需求。通常，这需要加固或稳定，这可能会增加碳足迹和制造成本。本研究探讨了使用目前缺乏有效利用途径的混凝土回收粉末废物（水合水泥粉，HCP）的可行性。HCP 主要由水合水泥和细粉组成，具有潜在的胶凝特性。我们研究了将 HCP 纳入 EBM 的影响，以 20 %、25 %、30 %、35 %、40 % 和 60% 的比例用 HCP 代替土壤。评估包括收缩率、密度、压缩和弯曲强度、热性能（导热系数和比热容）和耐水性（斯威本加速侵蚀测试）的测试。此外，通过粒度分布、扫描电子显微镜、X 射线衍射和 X 射线荧光分析了原材料和所得 EBM 的微观结构。结果表明，HCP 提高了热阻（例如，使用 60% 的 HCP 时，热阻从 0.86 W m⁻1 K⁻1 降低到 0.4 W m⁻1 K⁻1），同时将热容量略微降低了约 30%。35% 的 HCP 可有效减轻雨水侵蚀。然而，HCP 孔隙率的增加会导致抗压强度和抗弯强度降低（例如，60% 的 HCP 分别从 3.4 MPa 和 1.2 MPa 降低到 0.5 MPa）。 总之，加入 35% 的 HCP 在技术上是可行的，在满足 EN41410 标准的同时生产出具有更高热阻的更轻的嵌段。