| 徐世烺,刘志凤.超高韧性水泥基复合材料干缩性能及其对抗裂能力的影响[J].水利学报,2010,41(12): |
| 超高韧性水泥基复合材料干缩性能及其对抗裂能力的影响 |
| Drying shrinkage behavior of ultra high toughness cementitious composites and its influence on anti-cracking capacity |
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| DOI： |
| 中文关键词: 超高韧性水泥基复合材料 多点开裂 干燥收缩 收缩表达式 早期 |
| 英文关键词: UHTCC multiple fine cracking drying shrinkage shrinkage expression early age |
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| 中文摘要: |
| 新近研制的超高韧性水泥基复合材料 （UHTCC） 具有优良的韧性和能量吸收能力，在直接拉伸荷载作用下表现出应变硬化和多点开裂等特性。本文通过干燥收缩试验，在与素混凝土、纤维混凝土进行对比的基础上，评价了UHTCC的干缩性能。试验结果表明：UHTCC的干缩主要发生在早期；早期的湿养护可避免UHTCC水分的过快蒸发，减小其干缩速度，但是却使其最终的干缩值大大增加；PVA纤维对UHTCC的干缩值影响不大。通过抗裂能力参数，结合已有的约束收缩试验结果，对较大的干缩量并不有利约束条件下材料抗裂能力的传统概念进行了修正，指出对修复材料来说干缩量的大小仅仅表征了材料性能的一个物理参数，决定其材料抗裂能力的是其非线性变形能力的大小。最后给出了符合UHTCC干缩变形的收缩表达式。 |
| 英文摘要: |
| Ultra high toughness cementitious composites（UHTCC），has excellent toughness and remarkable
energy absorption ability. The drying shrinkage property of UHTCC was investigated and compared with
plain concrete and traditional fiber reinforced concrete by experiment. The results indicated that drying shrinkage of UHTCC mainly occurred at early age and the evaporation speed of water contained in the UHTCC can be slowed down by wet curing at early age，which leads to a reduction in the rate of drying shrinkage of UHTCC at early age，but results in a increase in ultimate drying shrinkage deformation. The PVA fiber has a little influence on the drying shrinkage of UHTCC. Combining cracking potential parameter with the test results of restrained shrinkage ohtained by the authors，the traditional concept which higher drying shrinkage strain has no avail on the anti-cracking capacity of restrained materials is revised. It can be considered that drying shrinkage strain is just a physics parameter for repair materials and it is the plastic straining performance that determines the anti-cracking capacity of materials. Finally the expression for describing the drying shrinkage deformation of UHTCC is presented. |
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