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水泥基灌浆料膨胀指标与凝结时间的关联性研究
作者：胡超凡，钱晓倩，方明晖，钱匡亮
（浙江大学 建筑工程学院，浙江 杭州 310058）
摘要：为探究水泥基灌浆料膨胀指标与凝结时间的关联性以及硬化后膨胀率的补偿收缩效果，研究了不同灌浆料的凝结时间、竖向膨胀率、自由与限制膨胀。结果表明：不同灌浆料的凝结时间差异很大，不能简单地以3 h为界区分塑性膨胀与硬化后膨胀；忽略了凝结时间的考量后，符合GB/T 50448—2015竖向膨胀率要求的灌浆料实际上可能只有塑性膨胀或硬化后膨胀两者之一，无法实现早期膨胀密实与后期提供膨胀应力的双重目标，更为合理的竖向膨胀率指标，应以初凝和终凝分别作为塑性膨胀的终止点和硬化后膨胀的起始点；灌浆料硬化后的膨胀率无法衡量补偿收缩的效果，24 h内持续膨胀才能提供补偿后期收缩的膨胀应力。
关键字：水泥基灌浆料；竖向膨胀率；凝结时间；自由膨胀；限制膨胀
中图分类号：TU57+8 文献标识码：A 文章编号：1001-702X（2020）11-0130-04
Research on the correlation between expansion index and setting time of cementitious grout
HU Chaofan，QIAN Xiaoqian，FANG Minghui，QIAN Kuangliang
（College of Civil Engineering and Architecture，Zhejiang University，Hangzhou 310058，China）
Abstract：To research the correlation between the cementitious grout expansion index with the setting time and the effect of the expansion rate after hardening on the shrinkage compensation，the setting time，vertical expansivity，limiting and free expansion of different grouting materials were studied. The results show that the setting time of different grouting materials is very different. It is not possible to distinguish plastic expansion from post-hardening expansion simply by taking 3 h as the boundary. After ignoring the setting time，the grouting material that meets the GB/T 50448—2015 vertical expansivity requirements may actually only have plastic expansion or post-hardening expansion. That cannot achieve the dual objectives of compaction by early expansion and providing expansion stress at later stages. For more reasonable vertical expansivity，the initial and final setting should be taken as the termination point of plastic expansion and the initial point of post-hardening expansion respectively. The expansion rate of grout after hardening cannot measure the effect of shrinkage compensation，and continuous expansion within 24 h can provide expansion stress to compensate for late shrinkage.
Key words：cementitious grout，vertical expansivity，setting time，free expansion，limiting expansion