石粉对机制砂混凝土早期收缩和开裂性能的影响研究

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中图分类号：TU525 文献标志码：A 文章编号：1005-8249（2025）02-0044-06

DOI：10.19860/j.cnki.issn1005-8249.2025.02.008

Abstract：To studytheinfluence of stone powder contentontheearlyshrinkageand cracking performance of manufactured concrete，the working performance，earlyshrinkage，early cracking，compressve strength，andpore distributionof manufacturedsandconcretewithdiffrentstrengthanddiferentcontentsweretested.Thetestresultsshowthattheaddtionof stonepowderisbeneficialtoimprovethewaterretention，ohesiveness，andanti-segregationperformanceofmanufacturedsand concrete but it willincrease theamount of waterreducing agent andearlyshrinkage strain of manufacturedsand concrete.An appropriate amount of stone powder is beneficial toimprovethecrackresistance and compressivestrength of manufacturedsand concrete，butexcesivestone powder willead tothedecreaseofcrackresistanceandcompressive strength.The stonepowder content in manufactured sand can be relaxed to 20 % for C3O concrete，and the content of stone powder should be controlled within 10 % for the C5O concrete.The optimum value of stone powder content in manufactured sand for concrete should be determinedincombinationwithengineringenvironmentandpracticaluse，which ismoreconducivetotheexpansionaplication of manufactured sand concrete in areas with poor sand resoures.

Key words： manufactured sand concrete； stone powder content；volume stability；microstructure

0 引言

近年来，为保护生态环境和实现可持续发展战略，禁采、限采天然砂的相关规定相继出台，这就导致作为混凝土主要原材料之一的河砂严重短缺，机制砂的市场需求出现急剧增长[1-2]。（剩余6724字）