Effect of Temperature on <scp><scp>C</scp></scp>₃<scp><scp>S</scp></scp> and <scp><scp>C</scp></scp>₃<scp><scp>S</scp></scp> + Nanosilica Hydration and <scp><scp>C</scp></scp>–<scp><scp>S</scp></scp>–<scp><scp>H</scp></scp> Structure

<jats:p>This study aimed to monitor the effect of temperature and the addition of nanosilica on the nanostructure of the <jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content>–<jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content>–<jats:styled-content style="fixed-case"><jats:roman>H</jats:roman></jats:styled-content> gel forming during tricalcium silicate (<jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content><jats:sub>3</jats:sub><jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content>) hydration. Two types of paste were prepared from a synthesized <jats:styled-content style="fixed-case"><jats:roman>T</jats:roman></jats:styled-content><jats:sub>1</jats:sub> <jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content><jats:sub>3</jats:sub><jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content>. The first consisted of a blend of deionized water and <jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content><jats:sub>3</jats:sub><jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content> at a water/solid ratio of 0.425. In the second, a 90 wt% <jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content><jats:sub>3</jats:sub><jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content> + 10 wt% of nanosilica blend was mixed with water at a water/solid ratio of 0.7. The pastes were stored in closed containers at 100% <jats:styled-content style="fixed-case">RH</jats:styled-content> and 25°C, 40°C, or 65°C. The hydration reaction was detained after 1, 14, 28, or 62 d with acetone, and then pastes were studied by <jats:sup>29</jats:sup><jats:styled-content style="fixed-case"><jats:roman>Si</jats:roman></jats:styled-content> magic angle spinning nuclear magnetic resonance (<jats:sup>29</jats:sup><jats:styled-content style="fixed-case"><jats:roman>Si</jats:roman> MAS NMR</jats:styled-content>).The main conclusion was that adding n<jats:styled-content style="fixed-case">SA</jats:styled-content> expedites <jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content><jats:sub>3</jats:sub><jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content> hydration at any age or temperature and modifies the structure of the <jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content>–<jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content>–<jats:styled-content style="fixed-case"><jats:roman>H</jats:roman></jats:styled-content> gel formed, two types of <jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content>–<jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content>–<jats:styled-content style="fixed-case"><jats:roman>H</jats:roman></jats:styled-content> gel appear. At 25°C and 40°C, more orderly, longer chain gels are initially (1 d) obtained as a result of the pozzolanic reaction between <jats:styled-content style="fixed-case">nSA</jats:styled-content> and portlandite (CH) (<jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content>–<jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content>–<jats:styled-content style="fixed-case"><jats:roman>H</jats:roman></jats:styled-content><jats:sub>II</jats:sub> gel formation). Subsequently, ongoing <jats:styled-content style="fixed-case"><jats:roman>C</jats:roman></jats:styled-content><jats:sub>3</jats:sub><jats:styled-content style="fixed-case"><jats:roman>S</jats:roman></jats:styled-content> hydration and the concomitant flow of dimers shorten the mean chain length in the gel.</jats:p>