机制砂对隧道衬砌混凝土收缩性能的影响  

Effect of Manufactured Sand on Shrinkage of Tunnel Lining Concrete

作　　者：宋广明 SONG Guangming(China Railway 11th Bureau Group Fourth Engineering Co.,Ltd.,Wuhan 430000,China)

机构地区：[1]中铁十一局集团第四工程有限公司,湖北武汉430000

出　　处：《材料科学与工程学报》2025年第1期90-96,共7页Journal of Materials Science and Engineering

摘　　要：使用机制砂制备铁路隧道衬砌混凝土是未来的发展趋势。衬砌混凝土是隧道工程的重要组成部分,由混凝土收缩导致的环向裂缝是其常见的缺陷。因此,研究采用机制砂后的衬砌混凝土收缩性能对保障隧道工程质量有重要意义。本研究对强度等级为C40的花岗岩机制砂混凝土(GSC)、凝灰岩机制砂混凝土(TSC)和河砂混凝土(RSC)的工作性能、抗压强度、收缩性能、早期抗裂性能进行了对比研究,并结合水分蒸发量和孔结构进行了内在机理分析。结果表明:在相同外加剂掺量下,两种机制砂混凝土的工作性能与河砂混凝土相近,较河砂混凝土具有更好的保坍性;机制砂混凝土的抗压强度可以满足设计要求,且凝灰岩机制砂混凝土在各龄期均较河砂混凝土表现出更高的抗压强度;若早期进行良好养护,机制砂不会增加混凝土的收缩,花岗岩机制砂还能显著降低收缩;若早期缺乏良好养护,两种机制砂均会增加混凝土早期收缩,早期抗裂性能也下降,增加衬砌混凝土环向开裂风险。The use of manufactured sand in the preparation of concrete for railway tunnel lining is a future development trend.Lining concrete is an important component of tunnel engineering,and circumferential cracks caused by concrete shrinkage are a common defect in lining concrete.Therefore,studying the shrinkage performance of lining concrete mixed by manufactured sand is of great significance for ensuring the quality of tunnel engineering.This paper aims to compare the workability,compressive strength,early cracking resistance,and shrinkage performance of granite manufactured sand concrete(GSC),tuff manufactured sand concrete(TSC),and river sand concrete(RSC)with a strength grade of C40.The underlying mechanism by considering water evaporation and pore structure was analyzed.The results indicate that both manufactured sands concrete exhibit similar workability to RSC when the same water reducer dosage is used,and they show better collapse retention than RSC.The compressive strength of the manufactured sand concretes meets the design requirements,and the TSC exhibits higher compressive strength than RSC at all ages.Additionally,manufactured sand does not increase the shrinkage if it is well cured in the early stage.In fact,granite manufactured sand can significantly reduce the shrinkage.However,if proper curing is lacking in the early stages,both manufactured sands will increase early shrinkage and decrease early cracking resistance,increasing the risk of radial cracking in lining concrete.

关 键 词：花岗岩机制砂 凝灰岩机制砂 隧道衬砌混凝土 抗压强度 收缩 孔结构 

分 类 号：TU528[建筑科学—建筑技术科学]