煤矸石混凝土静态抗压破坏机理及强度预测
Static compressive failure mechanism and strength prediction of coal gangue concrete
景宏君 1单俊伟 1李少平 2郭美蓉 1陈少杰 3高萌1
作者信息
- 1. 西安科技大学 建筑与土木工程学院,陕西 西安 710054;西安科技大学 道路工程研究中心,陕西 西安 710054
- 2. 榆林市公路局,陕西 榆林 719054
- 3. 西安科技大学 建筑与土木工程学院,陕西 西安 710054
- 折叠
摘要
为厘清煤矸石混凝土静态抗压强度变化规律和破坏机理,采用试验研究与模型预测相结合的方式,揭示煤矸石混凝土破坏过程、破坏形态、尺寸效应及水灰比对抗压强度的影响规律,剖析水灰比与抗压强度之间的数理关系,利用灰色理论建立GM(1,1)模型预测煤矸石混凝土抗压强度.结果表明:煤矸石具有大多数黏土岩的特性,即干燥时强度良好,浸水后易发生崩解;煤矸石混凝土的破坏可分为 3 个阶段(裂缝生成阶段、裂缝发展扩大阶段、混凝土破坏阶段)、3 种形态(粗骨料破坏、黏结破坏、水泥石破坏,且以粗骨料破坏为主);当水灰比由0.60 降至0.25 时,煤矸石混凝土抗压强度提高了2.67%～18.50%,满足C15、C20、C25、C30 4 个强度等级;由于煤矸石物理性质差,混凝土界面过渡区充斥大量微裂缝与孔洞,导致煤矸石混凝土尺寸效应强于普通混凝土;GM(1,1)模型预测值与实测值基本吻合,预测模型精度等级为 1 级.灰色理论可以有效预测煤矸石混凝土强度增长规律,煤矸石混凝土在实际应用前可采用灰色模型预测抗压强度.
Abstract
s:To clarify the strength variation law and failure mechanism of coal gangue concrete,a com-bination of experimental research and model prediction was adopted.Through the cube compressive strength test,the failure process,failure mode,size effect,and the influence of water cement ratio on the compressive strength of coal gangue concrete were revealed.The mathematical relationship between wa-ter cement ratio and compressive strength was analyzed,and a GM(1,1)model was established by u-sing grey theory to predict the compressive strength of coal gangue concrete.The results show that coal gangue has the characteristics of most clay rocks,that is,it has good strength when dry and is prone to disintegration after immersion in water.The failure of coal gangue concrete can be divided into three stages(crack generation stage,crack development and expansion stage,concrete failure stage)and three forms(coarse aggregate failure,bonding failure,cement stone failure,and mainly coarse aggregate fail-ure).When the water cement ratio decreases from 0.60 to 0.25,the compressive strength of coal gangue concrete increases by 2.67%to 18.50%,meeting the four strength levels of C15,C20,C25,and C30.Due to the poor physical properties of coal gangue,the transition zone of the concrete inter-face is filled with a large number of micro cracks and pores,resulting in a stronger size effect of coal gangue concrete than ordinary concrete.The predicted values of the GM(1,1)model are basically con-sistent with the measured values,and the accuracy level of the prediction model is level 1.The grey theory can effectively predict the strength growth law of coal gangue concrete,and the grey model can be used to predict the compressive strength of coal gangue concrete before practical application.
关键词
煤矸石混凝土/破坏过程/破坏机理/尺寸效应/GM(1,1)模型Key words
coal gangue concrete/failure process/failure mechanism/size effect/GM(1,1)model引用本文复制引用
基金项目
陕西省交通厅科技项目(21-21K)
陕西省交通厅科技项目(21-79B)
陕西省公路局科技项目(G21-04K)
榆林市科技局项目(CXY-2022-157)
陕西省博士后科研项目(2023BSHEDZZ310)
出版年
2024
国家科技期刊平台
NSTL
万方数据