Pervious concrete, developed to solve urban flooding and overloaded drainage issues, has limited strength due to its large void ratio. Reactive MgO cement (RMC) is a sustainable cement gaining strength through carbonation, which can have a more pronounced carbonation-induced enhancement in mechanical properties compared with Portland cement. However, its carbonation degree was limited due to the dense microstructure. To address both issues, pervious concrete using RMC was developed, and its void ratios were leveraged to facilitate the carbonation of RMC. Experimental results revealed that compared with that of samples cured under ambient environment (i.e. 4.7–15.7 MPa), the compressive strength of RMC-based pervious concrete cured under accelerated carbonation (11.2–39.7 MPa) and water/CO cycles (10.3–29.6 MPa) was enhanced by 77–278%. As the design void ratio increased from 0.15 to 0.30, the permeability coefficient of pervious concrete increased from 0.1 to 2.3 mm/s, while the carbonation of RMC-based pervious concrete also benefited from high void ratio, with the highest 28-day carbon sequestration ratio reaching 12.7%, as indicated by XRD, TGA tests and SEM observations. Furthermore, a mathematical model was established to estimate the thickness of cement paste on aggregates in pervious concrete, which was less than 1 mm and decreased as the design void ratio increased.

中文翻译：

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碳化对活性氧化镁基透水混凝土发展的影响

透水混凝土是为解决城市内涝和排水超载问题而开发的，但由于其空隙率较大，强度有限。活性氧化镁水泥（RMC）是一种通过碳化获得强度的可持续水泥，与波特兰水泥相比，它可以通过碳化引起更明显的机械性能增强。然而，由于微观结构致密，其碳化程度受到限制。为了解决这两个问题，开发了使用 RMC 的透水混凝土，并利用其空隙率来促进 RMC 的碳化。实验结果表明，与环境环境下（即4.7-15.7 MPa）养护的样品相比，在加速碳化（11.2-39.7 MPa）和水/CO循环（10.3-29.6 MPa）条件下养护的RMC基透水混凝土的抗压强度）增强了 77-278%。随着设计空隙率从0.15增加到0.30，透水混凝土的渗透系数从0.1增加到2.3mm/s，而RMC基透水混凝土的碳化也受益于高空隙率，28天固碳量最高XRD、TGA 测试和 SEM 观察表明，比率达到 12.7%。此外，还建立了数学模型来估算透水混凝土中骨料上水泥浆的厚度，该厚度小于1 mm，并且随着设计空隙率的增加而减小。