Construction spoil accounts for the main part of construction and demolition waste, the effective recycling of which has been paid less attention to by previous investigations. This work investigated the feasibility of utilizing waste spoil powder (WSP) ground from construction waste as partial cement replacement for preparing sustainable mortar, and a 800–1200 °C heat treatment was employed to modify the properties of WSP. The WSP with an irregular particle shape contains massive inert quartz, anorthite and kaoline, and mixing WSP reduces the hydration reaction and enlarges the pore structure of cement-based materials. However, new metakaolin and amorphous components are generated in heat-treated WSP, and heat-treated WSP has higher activity than untreated WSP; besides, the paste with heat-treated WSP has finer pore size than the paste with untreated WSP. The drying shrinkage of mortar increases by intermixing WSP; but the mix of heat-treated WSP reduces the drying shrinkage, and the maximum shrinkage of mortar with 30% WSP after 1200 °C treatment is 25.0% lower than that of plain mortar. Incorporating WSP reduces the mechanical strength and meanwhile increases the water absorption of mortar, but the mortar including heat-treated WSP has higher strength and lower water absorption than the mortar with untreated WSP. Decreasing WSP particle size further improves the properties of WSP blended mortar. It is noticed that incorporating heat-treated WSP together with active mineral admixture can prepare sustainable mortar with similar mechanical strength and lower water absorption than plain mortar without WSP.

建筑弃土是建筑垃圾和拆迁垃圾的主要组成部分，以往的调查对有效回收利用的关注较少。本工作研究了利用建筑垃圾磨碎的废弃弃土粉（WSP）作为部分水泥替代品制备可持续砂浆的可行性，并采用 800-1200 ℃热处理来改变 WSP 的性能。颗粒形状不规则的 WSP 含有大量惰性石英、钙长石和高岭土，混合 WSP 可减少水化反应，扩大水泥基材料的孔隙结构。然而，经过热处理的 WSP 会产生新的偏高岭土和无定形成分，热处理的 WSP 比未处理的 WSP 具有更高的活性；此外，经过热处理的 WSP 浆料比未经处理的 WSP 浆料具有更细的孔径。干燥收缩率通过混合 WSP 增加砂浆的用量；但热处理WSP的混合降低了干燥收缩率，30% WSP的砂浆经1200℃处理后的最大收缩率比普通砂浆低25.0%。加入WSP降低了砂浆的机械强度，同时增加了砂浆的吸水率，但加入热处理WSP的砂浆比未处理WSP的砂浆强度更高，吸水率更低。降低 WSP 粒径可进一步改善 WSP 混合砂浆的性能。值得注意的是，将热处理过的 WSP 与活性矿物外加剂结合在一起，可以制备出具有与不含 WSP 的普通砂浆相似的机械强度和更低的吸水率的可持续砂浆。