To promote the sustainable use of coal gangue in situ, coal gangue concrete (CGC) and BFRP-confined CGC have been explored to be supporting members in underground mines, where long-term sustained loads lead to significant creep deformation, affecting structural performance. Thus, 24 unconfined CGC and 36 BFRP-confined CGC specimens were tested, considering the effect of inner CGC strength, BFRP layer and stress-to-strength ratio on the compressive and creep behavior. The results reveal that the peak strength of BFRP-confined CGC improves by 29.9 %–63.7 %, and the ultimate strain is enhanced a lot due to the BFRP confinement, when compared with unconfined CGC. Other conditions being the same, a higher CGC strength, thicker BFRP layer and lower stress-to-strength ratio lead to a lower creep deformation. Furthermore, based on the ACI 209 model, the creep model of unconfined CGC was modified incorporating CGC strength. More importantly, parameter analysis by the creep deformation calculation model shows that the deformation of BFRP-confined CGC decreases by 15.3 % when the relative humidity increases from 70 % to 100 %.

中文翻译：

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无侧限和 BFRP 约束煤矸石混凝土的蠕变特性及模型


为了促进煤矸石的原位可持续利用，已经探索了煤矸石混凝土 （CGC） 和 BFRP 约束的 CGC 作为地下矿井的支撑构件，其中长期持续载荷会导致显着的蠕变变形，影响结构性能。因此，考虑了 CGC 内部强度、BFRP 层和应力强度比对压缩和蠕变行为的影响，测试了 24 个非约束 CGC 和 36 个 BFRP 约束 CGC 试件。结果表明，与非受限 CGC 相比，BFRP 约束的 CGC 的峰值强度提高了 29.9 %–63.7 %，并且由于 BFRP 约束，极限应变大大增强。在其他条件相同的情况下，较高的 CGC 强度、较厚的 BFRP 层和较低的应力强度比会导致较低的蠕变变形。此外，在 ACI 209 模型的基础上，结合 CGC 强度对无侧限 CGC 的蠕变模型进行了改进。更重要的是，蠕变变形计算模型的参数分析表明，当相对湿度从 70 % 增加到 100 % 时，BFRP 约束的 CGC 变形减少了 15.3 %。