丁苯乳液和超高分子质量聚乙烯纤维对砂浆抗弯

关键字：丁苯乳液,UHMW-PE纤维,水泥砂浆,初裂应力,初裂应变

（同济大学 先进土木工程材料教育部重点实验室，上海  201804）
 

    摘要：通过三点弯曲试验，研究了丁苯乳液和超高分子质量聚乙烯（UHMW-PE）纤维对砂浆抗弯性能的影响。研究发现，单掺丁苯乳液时，聚合物改性砂浆的初裂应力和抗折强度随着聚灰比的增加先提高后降低，且初裂应力和抗折强度相差不大；而初裂应变和最大负荷荷载所对应的应变（强度应变）总体上都随聚灰比的增大而增加，最高分别提高3倍和4倍。1.2%UHMW-PE纤维与丁苯乳液复掺时，聚合物改性砂浆的初裂应力随着聚灰比增大而增加，且抗折强度远高于初裂应力，而抗折强度随聚灰比增加而降低。纤维的掺入可以大幅度提高聚合物改性砂浆的初裂应变和强度应变，最高分别提高9倍和96倍。除聚灰比为0.3的砂浆，掺入1.2%的纤维都降低了砂浆的初裂应力。
    关键词：丁苯乳液；UHMW-PE纤维；水泥砂浆；初裂应力；初裂应变；抗折强度；强度应变
    中图分类号：TU57+8.12        文献标识码：A        文章编号：1001-702X（2017）02-0094-05

Influences of SBR latex and UHMW-PE fiber on bending properties of mortar
CHEN Weideng，HAN Dongdong，ZHONG Shiyun
（Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education，Tongji University，Shanghai 201804，China）

    Abstract：Influences of SBR latex and UHMW-PE fiber on the bending properties of mortar were investigated by three-point bending test. The results show that，with regard to the mortar without fiber，the stress of mortar at the initial crack and strain at flexural strength first increase and then decrease with the increase of polymer/cement ratio（P/C），and they have very little differ-
ence. Besides，the strain（strength strain） of mortar at the initial crack and maximum load increased with the increase of P/C in general，and reached the maximum at 3 times and 4 times respectively. When the fiber is present，the stress at initial crack of mortar increased with P/C increase，while flexural strength of mortar shows first increase then decrease，and the flexural strength of mortar is much higher than the stress at initial crack. The presence of fiber can improve the strain at initial crack and the strain at flexural strength significantly，the maximum of strain is 9 times and 96 times. The stress of mortar with 1.2% fiber at initial crack can be decreased except P/C is of 0.3.
    Key words：SBR latex，UHMW-PE fiber，cement mortar，stress at initial crack，strain at initial crack，flexural strength，strain at flexural strength