The influence of polymers on the hydration of portland cement phases analyzed by soft x-ray transmission microscopy
The influence of polymers on the hydration of portland cement phases analyzed by soft x-ray transmission microscopy
复制标题
DOI：
10.1016/j.cemconres.2006.05.010
复制
发表时间：
2006-08
影响因子：
11.4
通讯作者：
D. A. Silva;P. Monteiro
中科院分区：
文献类型：
--
作者：
D. A. Silva;P. Monteiro
软X射线透射显微镜，它允许在正常压力下原位观察水泥的湿样品的高空间分辨率（25 nm），用于观察和比较两种聚合物-水溶性聚合物（HPMC -羟丙基甲基纤维素）和乳胶[EVA-聚（乙烯-共-乙酸乙烯酯）]对C3 S和C3 A的早期水化的影响。这些聚合物用于改善新鲜和硬化砂浆和混凝土的性能，特别是当需要粘合特性时。图像显示，纤维素醚延迟了水泥颗粒的水化，并促进了内部产物而不是外部产物的形成。另一方面，伊娃颗粒在水化的C3 S颗粒周围聚集，并在复合材料微观结构的发展中起成核剂的作用。虽然HPMC略微改变了C3 A水化的方面，但伊娃在水化的早期阶段抑制甚至阻止钙矾石晶体的形成，并且导致聚集在水化的C3 A颗粒周围的小而明亮的颗粒云。
The soft X-ray transmission microscope, which allows the in situ observation of wet samples of cement at normal pressures with high spatial resolutions (25 nm), was used to observe and compare the effects of two polymers — a water soluble polymer (HPMC — hydroxypropyl methylcellulose) and a latex [EVA-poly(ethylene-co-vinyl acetate)] on the early hydration of C3S and C3A. These polymers are used to modify the properties of fresh and hardened mortars and concretes, especially when adhesive characteristics are required. The images show that the cellulose ether delays the hydration of the cementitious particles and promotes the formation of inner products rather than outer products. On the other hand, EVA particles agglomerate around the hydrating C3S grains, and act as nucleation agents in the development of the composite microstructure. While HPMC slightly changed the aspect of C3A hydration, EVA inhibited or even prevented the formation of ettringite crystals during the early stage of hydration, and resulted in a cloud of small, bright particles concentrated around the hydrating C3A grains.