This study investigates the recycling of pulverized hardened concrete (PHC) as a cementitious precursor in one-part alkali-activated cements. Two sodium silicate activators were compared: a commercially available option and an alternative derived from waste glass. Pastes with varying PHC:activator ratios (70:30 to 90:10) were cured for 24h at 20, 60 and 80 °C, then completed 28-days at 20 °C in air and underwater. Higher initial curing temperatures promoted early strength, but all pastes exhibited continued hydration and strength gains at 20 °C. All pastes displayed hydraulic characteristics. The PHC with the waste glass-based activator achieved 28-day compressive strengths up to 20 MPa for 70–80% PHC. These cements showed significantly lower CO2 emissions, embodied energy, and cost compared to those prepared with the commercial activator and a Portland cement. This research lays the groundwork for further investigations on sustainable precursors and activators in alkali-activated cements, aiming to optimize binder properties for broader applications.

中文翻译：

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使用废玻璃基硅酸钠，将粉状混凝土作为碱性单组分水泥中的水泥基前体进行回收


本研究调查了粉状硬化混凝土 （PHC） 作为单组分碱活化水泥中的水泥前体的回收利用。比较了两种硅酸钠活化剂：一种市售选择和一种来自废玻璃的替代品。具有不同 PHC：活化剂比例（70：30 至 90：10）的糊状物在 20、60 和 80 °C 下固化 24 小时，然后在 20 °C 下在空气和水下固化 28 天。较高的初始固化温度促进了早期强度，但所有浆料在 20 °C 时都表现出持续的水化和强度增加。 所有浆料均显示出水力特性。使用废玻璃基活化剂的 PHC 实现了 28 天的抗压强度，对于 70-80% 的 PHC，最高可达 20 MPa。与使用商业活化剂和波特兰水泥制备的水泥相比，这些水泥的二氧化碳排放量、隐含能源和成本显著降低。这项研究为进一步研究碱活化水泥中的可持续前驱体和活化剂奠定了基础，旨在优化粘结剂性能以获得更广泛的应用。