Reactive magnesia cement (RMC) is an emerging class of low-alkaline and CO-sequestering binder, which can mitigate the deterioration of GFRP reinforcements induced by a high-alkaline environment, e.g., in Portland cement. This study investigated the slip behavior of GFRP rebar embedded in RMC composite, which varies with carbonation depth significantly. The variation of the interfacial bond was determined by a specially designed push-out test of the GFRP core; the variation of the carbonation degree and microstructure was examined by SEM-EDX, MIP, XRD, TGA, FTIR, and acid digestion tests. Both properties demonstrated a similar trend, decreasing rapidly with increasing depth. A new finite element model that considers the depth-dependency of the matrix compositions and the rebar-to-matrix interfacial bond is established. It can predict the constitutive bond-slip behavior of a long GFRP rebar embedded in an RMC composite with non-uniform carbonation.

中文翻译：

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深度依赖的碳化对 GFRP 钢筋与活性氧化镁水泥基复合材料之间界面强度的影响

反应性氧化镁水泥（RMC）是一类新兴的低碱性和 CO2 封存粘合剂，可以减轻高碱性环境（例如波特兰水泥）引起的 GFRP 增强材料的劣化。本研究研究了嵌入 RMC 复合材料中的 GFRP 钢筋的滑移行为，该行为随碳化深度的变化而显着变化。界面粘合的变化是通过专门设计的 GFRP 芯材推出测试来确定的；通过SEM-EDX、MIP、XRD、TGA、FTIR和酸消解测试检查碳化度和微观结构的变化。两种特性表现出类似的趋势，随着深度的增加而迅速下降。建立了一种新的有限元模型，该模型考虑了基体成分的深度依赖性和钢筋与基体界面结合。它可以预测嵌入具有不均匀碳化的 RMC 复合材料中的长 GFRP 钢筋的本构粘结滑移行为。