Chen Xu, Kim Eric, Suraneni Prannoy, Struble Leslie
Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 1111 Engineering Drive UCB 428, Boulder, CO 80309, USA.
ExxonMobil Research & Engineering Company, North American Growth Venture, Olefins Furnaces, 3525 Decker Drive, Baytown, TX 77520, USA.
Materials (Basel). 2020 Dec 18;13(24):5784. doi: 10.3390/ma13245784.
For geopolymers (usually composed of unreacted precursor and gel), the compressive strength is controlled by two factors. The first is the degree of reaction, or, equivalently, the amount of gel formed, including any calcium silicate hydrate gel in calcium-containing mixtures. The second factor is the gel composition, generally given by the Si/Al ratio. These two parameters are interrelated for typical silicate-activated metakaolin geopolymers. By separating out effects of Si/Al ratio and degree of reaction, this study quantitatively correlates the degree of reaction with the compressive strength of metakaolin-based geopolymers with and without calcium. Solid-state Si nuclear magnetic resonance (NMR) aided with chemical extractions was used to determine gel amounts and composition for several geopolymer mixtures. The compressive strength was also measured for each mixture at 7 days. Both the increase of Na/Al ratio in mixtures without calcium and addition of external calcium increased the degree of reaction, and compressive strength correlated linearly (R > 0.88) with the degree of reaction.
对于地质聚合物（通常由未反应的前驱体和凝胶组成），抗压强度受两个因素控制。第一个因素是反应程度，或者等效地说，是形成的凝胶量，包括含钙混合物中的任何硅酸钙水合物凝胶。第二个因素是凝胶组成，通常由硅铝比给出。对于典型的硅激活偏高岭土地质聚合物，这两个参数是相互关联的。通过分离硅铝比和反应程度的影响，本研究定量地关联了有钙和无钙偏高岭土基地质聚合物的反应程度与抗压强度。采用化学萃取辅助的固态硅核磁共振（NMR）来测定几种地质聚合物混合物的凝胶量和组成。还在7天时测量了每种混合物的抗压强度。无钙混合物中钠铝比的增加以及外部钙的添加均提高了反应程度，并且抗压强度与反应程度呈线性相关（R>0.88）。
