预湿砂浆颗粒对高强混凝土早期自收缩的影响

关键字：预湿砂浆,颗粒,高强混凝土,早期,自收缩

（1.安徽理工大学 土木建筑学院，安徽 淮南  232001；
2.中国科学技术大学 近代力学系，中国科学院材料力学行为和设计重点实验室，安徽 合肥  230027）
 

    摘要：使用水灰比为0.5的早龄期砂浆颗粒对高强混凝土实施了内养护，研究了预湿砂浆颗粒对高强混凝土早期自收缩、抗压强度和显微结构的影响。结果表明：预湿砂浆颗粒可降低高强混凝土早期自收缩，掺量越大，减缩效果越显著，且适当的掺量对抗压强度影响较小；预湿砂浆颗粒掺量为12%时，可降低平均自收缩46.6%，而28 d强度仅降低6.7%；预湿砂浆颗粒是一种活性内养护载体，在混凝土中会继续水化，可改善水泥孔隙结构，提高界面密实性。
    关键词：内养护；预湿砂浆颗粒；自收缩；高强混凝土
    中图分类号：TU528.31        文献标识码：A        文章编号：1001-702X（2017）09-0001-04

Influence of pre-wetted mortar particles on the early-aged autogenous shrinkage of high-strength concrete
CHEN Peiyuan1，MA Honghao2，WANG Yuxuan1
（1.Institute of Civil Engineering and Construction，Anhui University of Science and Technology，Huainan 232001，China；
2.CAS Key Laboratory of Mechanical Behavior and Design of Materials（LMBD），Department of Modern Mechanics，
University of Science and Technology of China，Hefei 230027，China）

    Abstract：Early-age pre-wetted mortar particles with W/C of 0.5 were used as internal curing agent to investigate the influence on the early-age autogenous shrinkage，compressive strength and microstructure of high-strength concrete. Results showed that mortar particles as internal curing agent could mitigate the autogenous shrinkage of high-strength concrete，higher amount of added pre-wetted mortar particles could lead to more reduction of autogenous shrinkage. Proper amount of pre-wetted mortar particles would not significantly reduce the compressive strength，and 12% substitution ratio of sand by mortar particles could reduce 46.6% of the average autogenous shrinkage，which led to a reduction of the 28 day compressive strength at only 6.7%. Mortar particles are reactive internal curing agent，which allows further hydration reaction within concrete，thus，refining the porosity and strengthening the microstructure of cement paste surrounding mortar particles.
    Key words：internal curing，pre-wetted mortar particles，autogenous shrinkage，high-strength concrete