The mechanical, physical, and chemical changes due to oxides molar ratios (SiO₂/Al₂O₃ and SiO₂/CaO), and various Na₂O concentrations of treated palm oil fuel ash (TPOFA)‐based alkali‐activated mortar (AAM) after being exposed to different elevated temperatures up to 1,000°C were investigated. The source materials (SMs) and alkaline activator (AA) were used as the main base material to produce the AAM. The SMs consist of TPOFA with and without mineral additives (Ca(OH)₂, Al(OH)₃, and silica fume (SF)). The AA was characterized by various Na₂O concentrations of 7.1, 6.0, and 5.5% relative to the AAB weight. The results indicated that the relative compressive strength (CS) improved significantly from 9.20 to 34.62% after being exposed to 800°C. This was mainly due to the decrease in the total oxide's ratio of SiO₂/Al₂O₃ and SiO₂/CaO from 14.84 and 6.98% to 4.27 and 2.03%, respectively. The relative CS has increased from 0.0 to 101.38% after exposed to 1,000°C when Na₂O concentration reduced from 7.1 to 5.5%. This was due to the formation of more N–A–S–H and C–A–S–H gel binders as indicated at 28 days, which were transformed to nepheline (NaAl(SiO₄)) and wollastonite (CaSiO₃) phases after exposure to 800°C and 1,000°C, respectively.

中文翻译：

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SiO2，Al2O3，CaO和Na2O对碱活化处理过的棕榈油燃料粉煤灰基砂浆高温性能的影响

由于氧化物摩尔比（SiO ₂ / Al ₂ O ₃和SiO ₂ / CaO）以及各种浓度的Na ₂ O处理过的棕榈油燃料灰（TPOFA）基碱活化砂浆（在暴露于高达1,000°C的不同高温后进行了研究。原料（SMs）和碱性活化剂（AA）被用作生产AAM的主要基础材料。SM由含有和不含矿物添加剂（Ca（OH）₂，Al（OH）₃和硅粉（SF））的TPOFA组成。该AA的特征在于各种Na ₂相对于AAB重量，O浓度为7.1％，6.0％和5.5％。结果表明，暴露于800°C后，相对压缩强度（CS）从9.20％显着提高到34.62％。这主要是由于SiO ₂ / Al ₂ O ₃和SiO ₂ / CaO的总氧化物比从14.84和6.98％降低到4.27和2.03％。当Na ₂ O浓度从7.1％降低到5.5％时，暴露于1,000°C后相对CS从0.0增加到101.38 ％。这是由于在28天时形成了更多的N–A–S–H和C–A–S–H凝胶粘合剂，这些粘合剂已转化为霞石（NaAl（SiO ₄））和硅灰石（CaSiO ₃）分别暴露于800°C和1,000°C之后的阶段。