摘要
Abstract
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Key words
Granite manufactured sand/Tuff manufactured sand/Tunnel lining concrete/Compressive strength/Shrinkage/Pore structure分类
建筑与水利
