Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
DMAT srl, Udine, 33100, Italy.
Sci Adv. 2023 Jan 6;9(1):eadd1602. doi: 10.1126/sciadv.add1602.
Ancient Roman concretes have survived millennia, but mechanistic insights into their durability remain an enigma. Here, we use a multiscale correlative elemental and chemical mapping approach to investigating relict lime clasts, a ubiquitous and conspicuous mineral component associated with ancient Roman mortars. Together, these analyses provide new insights into mortar preparation methodologies and provide evidence that the Romans employed hot mixing, using quicklime in conjunction with, or instead of, slaked lime, to create an environment where high surface area aggregate-scale lime clasts are retained within the mortar matrix. Inspired by these findings, we propose that these macroscopic inclusions might serve as critical sources of reactive calcium for long-term pore and crack-filling or post-pozzolanic reactivity within the cementitious constructs. The subsequent development and testing of modern lime clast-containing cementitious mixtures demonstrate their self-healing potential, thus paving the way for the development of more durable, resilient, and sustainable concrete formulations.
古罗马混凝土历经千年仍得以保存，但人们对其耐久性的机械理解仍然是一个谜。在这里，我们使用一种多尺度相关元素和化学绘图方法来研究残留石灰碎屑，这是一种普遍存在且引人注目的矿物成分，与古罗马灰浆有关。这些分析共同提供了对灰浆制备方法的新见解，并提供了证据表明罗马人采用了热混合方法，使用生石灰与熟石灰结合使用，或者代替熟石灰，创造了一个环境，使高表面积骨料尺度的石灰碎屑保留在灰浆基质中。受这些发现的启发，我们提出这些宏观夹杂物可能是长期孔和裂缝填充或水泥结构内后火山灰反应的重要活性钙源。现代含有石灰碎屑的水泥混合物的后续开发和测试证明了它们的自修复潜力，从而为开发更耐用、更有弹性和更可持续的混凝土配方铺平了道路。
