Linkage of multi-scale performances of nano-CaCO3 modified ultra-high performance engineered cementitious composites (UHP-ECC)
Linkage of multi-scale performances of nano-CaCO3 modified ultra-high performance engineered cementitious composites (UHP-ECC)
复制标题
纳米碳酸钙改性超高性能工程水泥基复合材料（UHP-ECC）多尺度性能的联系
DOI：
10.1016/j.conbuildmat.2019.117418
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发表时间：
2020-02-20
影响因子：
7.4
通讯作者：
Bai, Yu-Lei
中科院分区：
文献类型：
--
作者：
Ding, Yao;Liu, Jie-Peng;Bai, Yu-Lei
本文研究了不同含量（即，0-4%水泥质量分数）对超高性能工程水泥基复合材料（UHP-ECC）水化、微观结构和力学性能的影响，阐明了UHP-ECC多尺度性能的内在联系。在微观尺度上，首次进行了热演化分析，结果表明，由于其核化和稀释作用，NC加速了UHP-ECC基质的水化热。采用热重/差热重分析方法研究了NC改性UHP-ECC基体的相结构变化，证实了NC的填料作用。压汞实验表明，随着NC含量的增加，材料的孔隙率和临界孔径均减小，当NC含量达到3%时，材料的孔隙率随着NC含量的增加而增大。最后，用扫描电镜观察了超高分子量聚乙烯纤维表面及纤维-基体界面的形貌。在细观尺度下，进行了单纤维拔出试验，结果表明，当NC含量为3%时，纤维与基体之间的摩擦应力达到最大值，这与MIP试验结果相一致。在宏观尺度上，提高UHP-ECC的压缩，拉伸和弯曲性能的最佳NC剂量被发现是3%，这是强有力的支持，在微观和细观尺度上获得的结果。因此，UHP-ECC的微观，介观和宏观尺度的性能之间表现出强烈的联系，和微观和介观尺度的性能诱导的复合材料水平上的UHP-ECC的力学性能的决定性影响。(C)2019爱思唯尔有限公司版权所有。
This paper investigated the effects of nano-CaCO3 (NC) with different contents (i.e., 0-4% by mass of cement) on hydration, micro-structure and mechanical properties of ultra-high performance engineered cementitious composites (UHP-ECC) and clarified the inherent relations of multi-scale performances of UHP-ECC. At the micro-scale, the heat evolution analysis was firstly conducted and the results showed that NC accelerated the heat of hydration of UHP-ECC matrices due to its nucleation and dilution effect. Then, the phase developments of NC modified UHP-ECC matrices were discussed using the thermal gravimetric analysis/differential thermal gravimetric analysis, which proved the filler effect of NC. Mercury intrusion tests (MIP) indicated that not only the porosity but also the critical pore size decreased with the increase of NC content up to 3%, beyond which the porosity increased due to the agglomerate of NC. Finally, the morphologies of ultra-high molecular weight polyethylene fiber surfaces and fiber-matrix interfaces were observed by scanning electron microscope. At the meso-scale, single fiber pullout tests were conducted and verified that the frictional stress between fiber and matrix reached the maximum value with NC content of 3%, which was in accordance with the results of MIP tests. At the macro-scale, the optimal NC dosage to enhance the compressive, tensile and flexural properties of UHP-ECC was found to be 3%, which was strongly supported by the results obtained at micro- and meso-scale. Hence, intense linkages between the micro-, meso- and macro-scale performances of UHP-ECC were exhibited, and the micro- and meso-scale properties induced a decisive impact on the mechanical properties of UHP-ECC at composites level. (C) 2019 Elsevier Ltd. All rights reserved.