This work quantified the hierarchy of the influence of three common mixture design parameters on the compressive strength and the rate of strength increase over the long term of low-calcium fly ash geopolymer concrete (FAGC) through designing 16 mixtures by the orthogonal experimental design (OED) method. The parameters used in the study were liquid to fly ash (L/FA) ratio, sodium hydroxide concentration (SHC) and sodium silicate solution to sodium hydroxide solution (SS/SH) ratio. The L/FA ratio showed little effect on compressive strength when it was varied from 0.40 to 0.52. SHC showed the greatest influence on compressive strength with little impact on the rate of strength increase after the initial heat curing. Even though the SS/SH ratio showed a small effect on the initial compressive strength, it had a considerable influence on the rate of strength increase over the long term. It was found that the compressive strength at 480 days was positively related to the Na2O/SiO2 molar ratio when it was varied from 0.49 to 0.80 and the Si/Al molar ratio was increased up to 1.87. Analysis of the failure types of specimens demonstrated that compressive strength of FAGC was associated with the strength of the mortar–aggregate interface zone (MAIZ).

中文翻译：

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调查影响热固化粉煤灰地质聚合物混凝土长期抗压强度的各种因素和正交试验设计方法的使用

本工作通过正交试验设计 (OED) 设计了 ​​16 种混合物，量化了三种常见混合物设计参数对低钙粉煤灰地质聚合物混凝土 (FAGC) 长期抗压强度和强度增加率的影响层次。 ） 方法。研究中使用的参数是液体与飞灰 (L/FA) 的比率、氢氧化钠浓度 (SHC) 和硅酸钠溶液与氢氧化钠溶液 (SS/SH) 的比率。当 L/FA 比在 0.40 到 0.52 之间变化时，它对抗压强度的影响很小。SHC 对抗压强度的影响最大，而对初始热固化后强度增加率的影响很小。尽管 SS/SH 比对初始抗压强度的影响很小，从长远来看，它对力量的增长速度有相当大的影响。结果表明，当 Na2O/SiO2 摩尔比从 0.49 变化到 0.80，Si/Al 摩尔比增加到 1.87 时，480 天的抗压强度与 Na2O/SiO2 摩尔比呈正相关。对试样破坏类型的分析表明，FAGC 的抗压强度与砂浆-集料界面区 (MAIZ) 的强度有关。