Faculty of Civil Engineering, Universiti Teknologi Malaysia, Johor Bahru, Johor, Malaysia.
Department of Building, University of Jos, PMB, Jos, 2084, Nigeria.
Environ Sci Pollut Res Int. 2024 Apr;31(17):25129-25146. doi: 10.1007/s11356-024-32786-0. Epub 2024 Mar 11.
Every structure might be exposed to fire at some point in its lifecycle. The ability of geopolymer composites to withstand the effects of fire damage early before it is put out is of great importance. This study examined the effects of fire on geopolymer composite samples made with high-calcium fly ash and alkaline solution synthesised from waste banana peduncle and silica fume. A ratio of 0.30, 0.35, and 0.4 was used in the study for the alkaline solution to fly ash. Also used were ratios of 0.5, 0.75, and 1 for silica oxide (silica fume) to potassium hydroxide ratio. The strength loss, residual compressive strength, percentage strength loss, relative residual compressive strength, ultrasonic pulse velocity, and microstructural properties of the thirteen mortar mixes were measured after exposure to temperatures of 200, 400, 600, and 800 °C for 1 h, respectively. The results reveal that geopolymer samples exposed to elevated temperatures showed great dimensional stability with no visible surface cracks. There was a colour transition from dark grey to whitish brown for the green geopolymer mortar and brown to whitish brown for the control sample. As the temperature rose, weight loss became more pronounced, with 800 °C producing the most significant weight reduction. The optimum mixes had a residual compressive strength of 25.02 MPa after being exposed to 200 °C, 18.72 MPa after being exposed to 400 °C, 14.04 MPa after being exposed to 600 °C, and 7.41 MPa after being exposed to 800 °C. The control had a residual compressive strength of 8.45 MPa after being exposed to 200 °C, 6.67 MPa after being exposed to 400 °C, 3.16 MPa after being exposed to 600 °C, and 2.23 MPa after being exposed to 800 °C. The relative residual compressive strength decreases for green geopolymer mortar are most significant at 600 and 800 °C, with an average decrease of 0.47 and 0.30, respectively. The microstructure of the samples revealed various phase changes and new product formations as the temperature increased.
每种结构都有可能在其生命周期的某个时刻暴露于火灾之下。因此，地质聚合物复合材料在火灾发生之前就具有抵御早期火灾破坏的能力是非常重要的。本研究考察了用高钙粉煤灰和由废香蕉叶柄和硅灰制成的碱性溶液合成的地质聚合物复合材料样品在火灾下的影响。研究中使用的碱性溶液与粉煤灰的比例为 0.30、0.35 和 0.4，硅氧化物（硅灰）与氢氧化钾的比例为 0.5、0.75 和 1。在分别暴露于 200、400、600 和 800°C 1 小时后，测量了 13 种水泥砂浆的强度损失、残余抗压强度、强度损失百分比、相对残余抗压强度、超声波脉冲速度和微观结构特性。结果表明，暴露于高温下的地质聚合物样品具有很好的尺寸稳定性，没有可见的表面裂缝。绿色地质聚合物水泥砂浆从深灰色变为灰白色，而对照样品则从棕色变为灰白色。随着温度的升高，重量损失变得更加明显，800°C 时的重量损失最大。在暴露于 200°C 时，最佳混合物的残余抗压强度为 25.02MPa，暴露于 400°C 时为 18.72MPa，暴露于 600°C 时为 14.04MPa，暴露于 800°C 时为 7.41MPa。对照样品在暴露于 200°C 时的残余抗压强度为 8.45MPa，暴露于 400°C 时为 6.67MPa，暴露于 600°C 时为 3.16MPa，暴露于 800°C 时为 2.23MPa。绿色地质聚合物水泥砂浆的相对残余抗压强度在 600°C 和 800°C 时下降最为显著，分别平均下降 0.47 和 0.30。随着温度的升高，样品的微观结构显示出各种相变化和新产物的形成。
