论文标题
反应性胶体凝胶中的蠕变：水泥水合的纳米力学研究
Creep in reactive colloidal gels: a nanomechanical study of cement hydrates
论文作者
论文摘要
从软聚合物凝胶到硬化的水泥糊，在恒定负载下的无定形固体表现出明显的时间依赖性变形，称为蠕变。这种现象的微观机制在无定形材料中尚不清楚，并且在密集的包装和化学反应性的颗粒系统中构成了更大的挑战。这两种特征都在由硅酸钙（C-S-H）纳米颗粒组成的水合水泥糊中显着，它们的填料密度随时间的函数而增加，而水泥水合正在发生。在水合的各个阶段，对大量样品进行纳米识别测试和孔隙度测量，我们表明保湿水泥糊的蠕变响应主要由粒子间距离控制，并且是（C-S-H）纳米颗粒之间的滑倒所致。我们的发现提供了对衰老颗粒材料中蠕变响应的微观机制的独特见解，从而铺平了用改善蠕变耐药性设计混凝土的道路。
From soft polymeric gels to hardened cement paste, amorphous solids under constant load exhibit a pronounced time-dependent deformation called creep. The microscopic mechanism of such a phenomenon is poorly understood in amorphous materials and constitutes an even greater challenge in densely packed and chemically reactive granular systems. Both features are prominently present in hydrating cement pastes composed of calcium silicate hydrate (C-S-H) nanoparticles, whose packing density increases as a function of time, while cement hydration is taking place. Performing nano-indentation tests and porosity measurements on a large collection of samples at various stages of hydration, we show that the creep response of hydrating cement paste is mainly controlled by the inter-particle distance and results from slippage between (C-S-H) nanoparticles. Our findings provide a unique insight into the microscopic mechanism underpinning the creep response in aging granular materials, thus paving the way for the design of concrete with improved creep resistance.
