高温下掺PPF的RPC立方体抗压性能

Compressive properties of cube for reactive powder concrete with polypropylene fibers at elevated temperature

摘要:

为了改善高温下活性粉末混凝土(RPC)的爆裂和抗压性能,完成了108个70.7 mm×70.7 mm×70.7 mm掺聚丙烯纤维(PPF)的活性粉末混凝土立方体试块高温下抗压试验．考察了PPF掺量对RPC高温爆裂的抑制效果,研究了温度和PPF掺量对高温下RPC立方体抗压性能的影响．结果表明:体积掺量0.3％的PPF能有效防止RPC爆裂,高温下RPC立方体抗压强度也相对较高;100 ℃时RPC的立方体抗压强度比常温低,200 ～ 600 ℃时立方体抗压强度相比100 ℃有所升高,700 ～ 800 ℃时立方体抗压强度相对600 ℃降低;20 ～ 100 ℃时RPC立方体抗压强度随PPF掺量的增大而降低,200 ～ 800 ℃时RPC立方体抗压强度随PPF掺量的增大而提高;100 ～ 500 ℃时掺PPF的RPC的立方体相对抗压强度小于普通混凝土和高强混凝土,600 ～ 800 ℃时掺PPF的RPC的立方体相对抗压强度则较大．基于试验结果,拟合出了不同PPF掺量的RPC高温下立方体抗压强度随温度变化的计算公式．

Abstract:

To improve the explosive spalling and compressive properties of reactive powder concrete (RPC) at elevated temperature, 108 cube specimens (70.7 mm×70.7 mm×70.7 mm) were prepared to study the compressive strength of RPC with polypropylene fibers (PPF). The influences of temperatures and PPF content on the spalling properties of RPC were investigated, and compressive strength of RPC with different temperatures and PPF content were studied. The experimental results show that PPF volume content of 0.3％ can prevent explosive spalling of RPC and significantly increase compressive strength. Compressive cube strength drops at 100 ℃ as compared to 20 ℃ and increases from 200 to 600 ℃, but drops again beyond 600 ℃; Compressive cube strength of the RPC was lower if the PPF content increases below 100 ℃, but was higher when the PPF content increases between 200 and 800 ℃; The relative compressive strength of RPC was lower below 500 ℃, but was higher between 600 and 800 ℃. Calculation formulas of the compressive strength at elevated temperature were obtained by fitting curve of experimental data considering PPF content when temperature varied.