Alkali binding in cement pastes Part I. The C-S-H phase
Alkali binding in cement pastes Part I. The C-S-H phase
复制标题
DOI：
10.1016/s0008-8846(99)00187-8
复制
发表时间：
1999-12-01
影响因子：
11.4
通讯作者：
Glasser, FP
中科院分区：
文献类型：
--
作者：
Hong, SY;Glasser, FP
钠和钾在水泥浆中的结合会影响混凝土的性能：例如，固体和浆体成分之间的碱平衡以及孔隙流体会影响与碱敏感骨料反应的可能性。然而，定量的结合潜力成膏固体已被证明是困难的，虽然许多经验数据可从孔隙流体分析。本研究在Ca：Si摩尔比为1.8、1.5、1.2和0.85的条件下制备了单相均匀C-S-H相，并与6种碱金属氢氧化物浓度（NaOH和KOH）反应，得到48种碱金属浓度和Ca：Si比的网格。在不到48小时内达到稳态碱分配。计算分配系数R-d以表示在20 ℃下碱在固相和水相之间的分配。R-d的数值与碱金属氢氧化物浓度无关，仅取决于Ca：Si比。证明了近似可逆性，因此R-d值在很宽的碱浓度范围内是C-S-H的常数。R-d值的趋势表明，随着其Ca：Si比的降低，碱结合到固体中得到改善。(C)2000爱思唯尔科技有限公司版权所有。
The binding of sodium and potassium into cement paste influences the performance of concrete: for example, alkali balances between solid and paste constituents and pore fluid affect the potential for reaction with alkali-susceptible aggregates. However, quantification of the binding potential into paste solids has proven to be difficult, although much empirical data are available from pore fluid analyses. In this study. single-phase homogeneous C-S-H phases have been prepared at Ca:Si molar ratios of 1.8, 1.5, 1.2, and 0.85 and reacted with six alkali hydroxide concentrations, both NaOH and KOH, between 1 and 300 mM, giving a grid of 48 alkali concentrations and Ca:Si ratios. A steady-state alkali partition is attained in less than 48 h. A distribution coefficient, R-d, was calculated to express the partition of alkali between solid and aqueous phases at 20 degrees C. The numerical value of R-d is independent of alkali hydroxide concentration and depends only on Ca:Si ratio. Approximate reversibility is demonstrated, so the R-d values are constants of a C-S-H over wide ranges of alkali concentration. The trend of R-d values indicates that alkali binding into the solid improves as its Ca:Si ratio decreases. (C) 2000 Elsevier Science Ltd. All rights reserved.