摘要
为研究不同养护温度下的湿喷混凝土强度演化规律,实现低温环境下强度的精准预测,根据吉林省东南部某金矿的湿喷配合比,对不同养护温度的湿喷混凝土开展抗压强度试验,采用扫描电镜(SEM)开展湿喷混凝土微观结构分析。研究结果表明:基于实验结果构建的ANN-PSO强度预测模型可以精准预测不同养护温度下的湿喷混凝土强度,其平均相对误差MRE仅1.706%,决定系数R^(2)为0.996;当养护温度由2℃增加到20℃时,湿喷混凝土的强度先快速增长,后增速减缓到基本稳定;本文提出的强度损伤系数随养护温度的增加逐渐减小,可以定量表征温度效应下混凝土强度的演化规律。低温抑制了水化反应,导致胶凝物质生成量少,无法满足混凝土由孔隙结构到致密胶结结构的发育需求,这种结构缺陷是强度受到损伤的本质原因。
In order to study the evolution law of wet shotcrete strength at different curing temperatures and realize the accurate prediction of strength under low temperature environment,the compressive strength test of wet shotcrete at different curing temperatures was carried out with the wet shotcrete mix ratio of a gold mine in the southeast of Jilin Province,and the microstructure analysis of wet shotcrete was carried out based on scanning electron microscopy(SEM).The results show that the ANN-PSO strength prediction model based on the experimental results can accurately predict the strength of wet shotcrete at different curing temperatures,and its mean relative error(MRE)is only 1.706%,determinate coefficient R^(2) is 0.996;when the curing temperature increases from 2℃to 20℃,the strength of wet shotcrete first increases rapidly,and then slows down to basically stable;the strength damage coefficient proposed in this paper gradually decreases with the increase of curing temperature,which can quantitatively represent the evolution rule of concrete strength under the effect of temperature;the low temperature inhibits the hydration reaction,resulting in less generation of cementitious substances,which can't meet the development demand of soil from pore structure to tight cemented structure.This structural defect is the essential reason for strength damage.
作者
李克庆
胡亚飞
韩斌
吉坤
张朋
LI Keqing;HU Yafei;HAN Bin;JI Kun;ZHANG Peng(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;Key Laboratory of Ministry of Education of China for Efficient Mining and Safety of Metal Mines,University of Science and Technology Beijing,Beijing 100083,China)
出处
《中南大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2021年第5期1581-1590,共10页
Journal of Central South University:Science and Technology
基金
国家重点研发计划项目(2018YFC1900603,2018YFC0604604)。
关键词
低温环境
强度发展
预测模型
微观结构
强度损伤
low temperature environment
strength development
prediction model
microstructure
strength damage