干湿循环作用下可溶盐对古建筑青砖劣化机理研究  

Study on Deterioration Mechanism of Blue Bricks of Ancient Buildings under Coupling Effect of Drying-wetting Cycles and Soluble Salts

作　　者：张景科[1,2] 张浩 王南[1] 白东明 张理想 索晨阳 ZHANG Jingke;ZHANG Hao;WANG Nan;BAI Dongming;ZHANG Lixiang;SUO Chenyang(School of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China;Key Laboratory of Mechanics on Disaster and Environment in Western China,the Ministry of Education of China,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]兰州大学土木工程与力学学院,甘肃兰州730000 [2]兰州大学西部灾害与环境力学教育部重点实验室,甘肃兰州730000

出　　处：《湖南大学学报（自然科学版）》2024年第11期197-207,共11页Journal of Hunan University:Natural Sciences

基　　金：白衣寺塔及菩萨殿保护修缮工程前期勘察研究项目(071100271)。

摘　　要：设置以Na_(2)SO_(4)、NaCl、MgSO_(4)及3种盐两两组合为条件的盐溶液,对青砖试样进行干湿循环试验,研究干湿循环中可溶盐对青砖质量、表面硬度、弹性波速和色差等的影响.从宏观、细观、微观多尺度及矿物成分变化角度分析青砖劣化机制.结果表明:试验前后试块质量和波速先上升后下降,硬度持续下降,抗压强度以及毛细吸水率等均有不同程度降低.Na_(2)SO_(4)对青砖表层及一定深度造成严重损伤;MgSO_(4)对砖中孔隙造成破坏,从而造成细小裂隙发育,但不会对青砖表层造成较大损伤;相较而言,NaCl仅对砖表层有微弱侵蚀.混合盐之间的相互作用会使其本身的结晶位置、数量及溶解度发生变化,从而产生不同的劣化模式.与单盐相比,混合盐室内劣化特征与实际赋存环境下的病害特征更相符.研究成果可为相关青砖文物的保护修复提供理论依据.Salt solutions based on Na_(2)SO_(4),NaCl,MgSO_(4)and their pairwise mixed salts were set up to conduct drying-wetting cycle tests on blue brick samples,and the effects of soluble salts in the drying-wetting cycles on the quality,surface hardness,elastic wave velocity and color difference of blue bricks were studied.The deterioration mechanism of blue bricks was analyzed from the perspectives of macroscopic,fine and microscopic multi-scale and mineral composition changes.The results show that the mass,wave velocity and hardness of the test all increase first and then decrease,and the hardness continues to decrease.The compressive strength and capillary water absorption rate are reduced to varying degrees.Na_(2)SO_(4)causes serious damage to the surface layer and a certain depth of blue bricks.MgSO_(4)destroys the pores in the brick,resulting in small cracks,but it is difficult to damage the surface layer of blue bricks.In contrast,NaCl only weakly erodes the surface layer of the brick.The interaction between the mixed salts changes their location of crystallization,quantity,and solubility,then it results in different deterioration patterns.Compared with single salt,the deterioration characteristics in the mixed salt chamber are more consistent with the disease characteristics in the actual occurrence environment.The results of this research will provide a reference for the protection and restoration of related buildings of brick cultural heritage.

关 键 词：砖结构 可溶盐 干湿循环 多尺度 劣化机理 

分 类 号：TU522[建筑科学—建筑技术科学]