Reusing thermoactivated waste paste/concrete powder for sustainable alkali-activated materials: Effects of thermoactivated temperature

作者：Miao Liu, Youchao Zhang, Changqing Wang, Zhiming Ma · 发表于：Construction and Building Materials · 年份：2024 · DOI：10.1016/j.conbuildmat.2024.136973 · 被引用次数：15 · 研究领域：Concrete and Cement Materials Research、Recycled Aggregate Concrete Performance、Innovative concrete reinforcement materials

The construction waste powder encompasses waste paste powder (WPP) and waste concrete powder (WCP), exhibiting an irregular microstructural morphology and containing mineral constituents like portlandite , C-S-H gel, calcite and quartz. Under the influence of thermal activation, certain hydrated products within construction waste powder undergo decomposition, concurrently generating new substances like CaO and C 2 S, which contribute to enhanced reactivity. Minerals within construction waste powder participate in polymerization reactions under alkali activation . Furthermore, alkali-activated mortar produced from thermally treated construction waste powder generate an increased quantity of C-A-S-H/N-A-S-H gel, resulting in a denser microstructure. When construction waste powder is thermally treated at temperatures ranging from 600°C to 800°C, the resulting alkali-activated construction waste powder mortar (AAWM) exhibits higher compressive strength . For example, the 28d compressive strength of AAWM prepared with WCP subjected to heat treatment at 800°C increased by 195.69 % compared to AAWM prepared with untreated WCP. With the increase in thermal treatment temperature of construction waste powder, the drying shrinkage of the resultant AAWM progressively diminishes, along with a gradual reduction in porosity and water absorption. For instance, the porosity and water absorption of AAWM prepared with WCP treated at 800°C decreased by 15.58 % and 18.67 % respectively compared t...