Abstract

Effect of particle size of two types of silica nanoparticles (SNPs) on hydration kinetics of tricalcium silicate (C₃S) and Portland cement was investigated. Two different types of SNPs were used in the present study, first one is the synthesized by sol-gel method (SNPs-sg) having particle size 30–70 nm, while the second one is the synthesized by Flame Spray Pyrolysis method (SNPs-fsp) having particle size <10 nm. The dosages of SNPs used in this study varied from 1–10% and water/binder ratio used for the hydration was 0.4. Rietveld analysis of XRD results show that at 4 h of hydration, the unhydrated content in control samples at 4 h hydration was ∼88% and in presence 1% SNPs-sg, it was ∼75%, however, in presence of SNPs-fsp, the content of unhydrated C₃S was ∼60%. Further, FTIR results reveal that in case of control samples at 1 h of hydration, the characteristic peaks of C₃S at 850 cm⁻¹ and 940 cm⁻¹ are present, while, with 1% SNPs-sg addition, reduction in the intensity C₃S peaks were observed showing acceleration in dissolution rate and a broader peak is observed at ∼1110 cm⁻¹ with 1% SNPs-fsp samples indicating the starting of polymerization in silicate chain of C-S-H gel.

摘要

研究了两种类型的二氧化硅纳米粒子 (SNP) 的粒径对硅酸三钙 (C _{3 S) 和硅酸盐水泥的水化动力学的影响。}本研究使用了两种不同类型的 SNP，第一种是通过溶胶-凝胶法合成的 (SNPs-sg)，粒径为 30–70 nm，而第二种是通过火焰喷雾热解法合成的 (SNPs- fsp) 粒径 <10 nm。本研究中使用的 SNP 剂量在 1-10% 之间变化，用于水合的水/粘合剂比率为 0.4。Rietveld 分析 XRD 结果表明，在水合 4 小时时，对照样品中水合 4 小时的未水合含量为～88%，在存在 1% SNPs-sg 的情况下，为～75%，然而，在存在 SNPs-fsp 的情况下, 未水合 C ₃的含量S 约为 60%。此外，FTIR 结果表明，在水合 1 小时的对照样品中，存在850 cm ^-1和 940 cm ^{-1处的 C} ₃ S特征峰，而添加 1% SNPs-sg 后，C 3 S 的特征峰减少观察到强度 C ₃ S 峰显示溶解速率加速，并且在 ~1110 cm ^{-1 处}观察到更宽的峰，其中 1% SNPs-fsp 样品表明 CSH 凝胶的硅酸盐链开始聚合。