Research on water transport behaviors and hydration characteristics of internal curing pavement concrete
Research on water transport behaviors and hydration characteristics of internal curing pavement concrete
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内养护路面混凝土水传输行为及水化特性研究
DOI：
10.1016/j.conbuildmat.2020.118714
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发表时间：
2020-07-10
影响因子：
7.4
通讯作者：
Liu, Huifen
中科院分区：
文献类型：
--
作者：
Qin, Xiao;Shen, Aiqin;Liu, Huifen
研究了内养护剂（高吸水性树脂）对路面混凝土水化特性和水化行为的影响。通过H-1核磁共振（NMR）试验定量分析了不同形态水的转化规律，并研究了混凝土板不同垂直深度处相对湿度的变化规律。采用等温量热法和热重法研究了内养护路面混凝土的水化过程。采用四点弯曲法对含SAP的试件的弯曲强度进行了测试。最后，通过分析SAP对道路混凝土的水传输行为、水化特性和微观结构特征，揭示了SAP对道路混凝土性能的增强机理。结果表明，粒径较小的SAP试样可以在较长时间内保持湿度补偿和水化增强过程。板坯内部的湿度梯度可以显著减小，从而可以减轻板坯内部的湿度翘曲应力。SAP虽然延缓了胶凝材料早期的水化进程，但从长期来看，它可以大大提高水化程度，有助于提高路面混凝土的抗裂性和密实性。内养护过程提高了集料-水泥基体界面过渡区（ITZ）的粘结性和微观结构的致密性。(C)2020爱思唯尔有限公司保留所有权利。
This paper presents the influence of internal curing agent (super absorbent polymer, SAP) on the water transport behaviors and hydration characteristics of pavement concrete. The H-1 nuclear magnetic resonance (NMR) test was performed to quantitatively analyze the transformation rule of different forms of water, and the variation rule of relative humidity in different vertical depths of concrete slab was also studied. Moreover, the isothermal calorimetry and thermogravimetry method were adopted to study the hydration process of internal curing pavement concrete. The flexural strength of specimens with SAPs were evaluated by the four-point bending method. Finally, the enhancement mechanism of SAP on the properties of pavement concrete was revealed through analyzing the water transport behaviors, hydration characteristics and microstructure characteristics. The results show that specimens with SAPs of smaller particle size could keep the humidity compensating and hydration enhancing process for a long time. The humidity gradient in the slab could be significantly reduced that might mitigate the humidity warping stress distributed in the slab. Although SAP delayed the hydration process of binding materials in the early age, it could greatly improve the hydration degree in the long term, which helps improving the crack resistance and the compactness of pavement concrete. The adhesion of aggregate-cement matrix interfacial transition zone (ITZ) and the compactness of microstructure was improved during the internal curing process. (C) 2020 Elsevier Ltd. All rights reserved.