西北寒旱区超长池体砂浆干燥收缩性能研究及干燥收缩模型的建立

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WU Shanxiong'，XUE Cuizhen²，YIN Kejian'，LIU Yuguo（1. China State Construction Engineering Corporation， Beijing 1OOO2O， China;

2. School of Civil Engineering，Lanzhou University of Technology，Lanzhou 73OO5O，China）

Abstract：Toaddresstheproblemofdryshrinkage cracking inultra-longconcrete polsinthearidandcold northwestregion， a systematicstudy wasconductedonthe efects of magnesium-based high-performance anti-cracking agents，flyashand slag powderon thedryshrinkage performance of concretespecimens，aswell asthe influence of diferentcuring environments （standardcuring，natural curing，andfilm-covered curing）onthedryshrinkage propertiesofthe specimens.Adry shrinkagemodelwasestablishedforthespecimensbasedontheCEB9OCodeModeltopredictthedryshrinkagerate.The results show thatasthecuring age increases，thedryshrinkagerateofultra-longconcrete pools increases graduall；Whenthe magnesium-based high -performance anti -cracking agent content is controlled at ⩽6% ，the dry shrinkage of concrete

specimensisimprovedtosomeextentunderdiferentcuring conditions；Thedryshrinkagerateof single-added flyash specimens issignificantlysmallerunderdiferentcuringconditions；Thedryshrinkage modelestablishedforconcretespecimens basedontheCEB9O Code Modelcanaccuratelypredicttheearlydryshrinkagerateofthe specimens.Theresearchresultsand theshrinkage modelcan provideatheoreticalbasis forfurther studiesonthedrying shrinkage deformation of massconcrete.

Key words：super long pol body；drying shrinkage；magnesium high performance anti-cracking agent；maintenance mode; shrinkage model

0 引言

超长池体混凝土长度、宽度及厚度较大，属于大体积混凝土，因此，明确西北寒旱区超长池体混凝土干缩变化规律，提出抑制超长池体混凝土开裂的措施是亟待解决的问题，

国内外学者关于大体积混凝土开裂开展了一定的研究，如Puertas等[1]研究表明在 21∘C 和相对湿度为 50% 条件下养护，掺 1% 聚丙烯纤维可显著降低砂浆的干燥收缩；Bakharev等[2]研究不同化学外加剂对砂桨干燥收缩性能影响，结果表明引气剂和减水剂可降低试件的干缩率；李飞等[3]研究了再生微粉对碱激发胶凝材料干缩性能的影响规律，结果表明再生微粉的“微集料”效应对碱激发胶凝材料的干燥收缩有较强的抑制作用；李馨等4研究不同水灰比对砂桨收缩性能的影响，结果表明水灰比对砂浆自收缩、干缩以及抗压强度的发展具有显著影响;陈迎5研究了机制砂石粉掺量对混凝土早期收缩和抗裂性能的影响，结果表明掺加适量石粉，可提高机制砂混凝土抗裂性能。（剩余6541字）