基于骨料特性差异的煤矸石混凝土干燥收缩模型  

Drying shrinkage model for coal gangue concrete based on difference of aggregate properties

作　　者：白国良[1,2] 刘瀚卿 王建文 朱可凡 代沐容 Bai Guoliang;Liu Hanqing;Wang Jianwen;Zhu Kefan;Dai Murong(School of Civil Engineering,Xi’an University of Architecture&Technology,Xi’an 710055,China;Key Lab of Structural Engineering and Earthquake Resistance,Ministry of Education,Xi’an University of Architecture&Technology,Xi’an 710055,China;Shaanxi Coal Group Shenmu Ningtiaota Mining Co.,Ltd.,Yulin 719000,China)

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]西安建筑科技大学结构工程与抗震教育部重点实验室,陕西西安710055 [3]陕煤集团神木柠条塔矿业有限公司,陕西榆林719000

出　　处：《土木工程学报》2023年第11期27-42,共16页China Civil Engineering Journal

基　　金：国家自然科学基金(52078410);陕西省科技计划成果推广项目(2020CGHJ-017);陕西省教育厅重点实验室项目(20JS071)。

摘　　要：为研究煤矸石粗骨料对混凝土干燥收缩的影响,试验分别以陕西榆神矿区3种典型矿井煤矸石为粗骨料,并以煤矸石取代率为变量,设计了10组干燥收缩试件。通过对试件在390d内干燥收缩变形的观测,分析煤矸石粗骨料对煤矸石混凝土收缩发展与收缩应变的影响,给出煤矸石混凝土的干燥收缩预测模型。试验表明:相较于普通混凝土,受煤矸石粗骨料吸返水特性影响,煤矸石混凝土干燥收缩发展存在滞后现象,且煤矸石粗骨料吸水率越高,其混凝土干燥收缩发展越慢,试件达到收缩稳定的龄期也越长。煤矸石粗骨料的表观密度与吸水率是影响煤矸石混凝土干燥收缩终值的2个主要指标,且随不同来源煤矸石粗骨料表观密度的降低、吸水率的增大,其混凝土的干燥收缩应变也随之增大。在CEB-FIP 90模型的基础上,分别引入了2个系数来考虑煤矸石粗骨料掺入对混凝土收缩发展与收缩终值的影响,并提出适用于煤矸石混凝土的干燥收缩预测模型。通过与试验数据对比,建议模型的预测精度较高,具有较好的适用性。To study the influence of coal gangue coarse aggregate(CGCA)on the drying shrinkage of concrete,three kinds of coal gangues from the Yushen mining area in Shaanxi were used as coarse aggregate,and 10 groups of drying shrinkage specimens were designed with the replacement ratio of coal gangue as variables.By testing the drying shrinkage deformation of the specimen within 390 days,the influence of CGCA on the shrinkage development and shrinkage strain of coal gangue concrete(CGC)was analyzed,and the drying shrinkage forecasting model of CGC was given.Test results show that:compared with the ordinary concrete,the development of drying shrinkage of CGC is slower due to the water absorption and return characteristics of CGCA.The higher the water absorption rate of the CGCA,the slower the drying shrinkage of the concrete,and the longer the age of reaching the shrinkage stability.The apparent density and water absorption of CGCA are two main indexes that affect the final value of drying shrinkage of CGC.With the decrease of apparent density and increase of water absorption of CGCA from different sources,the drying shrinkage strain of concrete increases.Based on the model suggested by CEB-FIP 90,two coefficients are introduced to consider the influence of CGCA on concrete drying shrinkage,and the drying shrinkage forecasting model suitable for CGC is proposed.Compared with the experimental data,the proposed model has good prediction accuracy and applicability.

关 键 词：煤矸石粗骨料 吸水率 表观密度 煤矸石混凝土 干燥收缩 预测模型 

分 类 号：TU528.09[建筑科学—建筑技术科学]