论文部分内容阅读
用低场核磁共振技术考察了HN-1型缓凝剂对水泥浆体中可蒸发水的横向弛豫时间(T2)及状态演变过程的影响。结果表明:在初始水化阶段的150 min内,水泥浆GR(添加缓凝剂HN-1的水泥净浆)的弛豫峰峰形和峰顶位置均无明显变化,水泥浆G(纯水泥净浆)的弛豫峰峰形变窄且峰顶位置从2.15 ms迁移至0.95 ms,说明缓凝剂HN-1主要通过改变水泥浆体中不同状态水的存留时间来改变其水化进程。随养护时间的延长,硬化水泥石W0.44和WR0.5中可挥发水弛豫峰分布范围分别从0.11~4.75 ms变为0.08~0.58 ms、0.24~4.23 ms变为0.11~2.35 ms,总体趋向于短弛豫时间,表明水泥石中毛细水逐渐向凝胶水和物理结合水转化,水泥石养护龄期延长至25 d时,其内部凝胶结构水含量超过90%。利用XRD考察了缓凝剂对水泥浆水化产物的影响,结果表明:缓凝剂只改变水泥浆水化过程,对最终水化产物晶型及晶型结构不存在任何影响。
The influence of HN-1 retarder on the transverse relaxation time (T2) and state evolution of water in cement paste was investigated by low-field NMR. The results showed that there was no significant change in the peak shape and peak position of the cement peak GR and the top of the cement grout GR (cement paste added with retarder HN-1) within 150 min of the initial hydration stage. The peak shape of the relaxation peak is narrowed and the peak position is shifted from 2.15 ms to 0.95 ms, which shows that the retarder HN-1 mainly changes the hydration process by changing the residence time of water in different states in the cement slurry. With the extension of curing time, the distribution range of volatile water relaxation peak in hardened cementite W0.44 and WR0.5 changed from 0.11 to 4.75 ms to 0.08 to 0.58 ms, 0.24 to 4.23 ms to 0.11 to 2.35 ms, respectively Which tends to short relaxation time, indicating that the capillary water in cement stone gradually transformed into gel water and physical combination water. When the curing age of cement stone was extended to 25 d, the water content of the internal gel structure exceeded 90%. The effects of retarders on the hydration products of cement slurries were investigated by XRD. The results show that the retarders only change the hydration process of cement slurries, and have no effect on the crystal form and crystal structure of the final hydration products.