硬化水泥浆体微米孔内氯化钠结晶压力作用数值模拟  

Numerical Simulation of Sodium Chloride Crystallization Pressure in Micro Pores of Hardened Cement Paste

作　　者：张泽 杨进波 张宇 ZHANG Ze;YANG Jinbo;ZHANG Yu(College of Water Conservancy and Civil Engineering,Shandong Agricultural University,Taian 271018,Shandong,China)

机构地区：[1]山东农业大学水利土木工程学院,山东泰安271018

出　　处：《硅酸盐学报》2025年第2期313-324,共12页Journal of The Chinese Ceramic Society

基　　金：山东省自然科学基金(ZR2023ME039,ZR2021MA067)。

摘　　要：干湿循环盐结晶破坏是以水泥基材料为代表的多孔材料劣化的主要问题之一。过饱和结晶压力假说仅说明结晶压力是造成水泥基材料破坏的主要原因,但对结晶过程中结晶压力的作用机理并没有做出解释。基于有限元法建立了NaCl结晶过程模型,通过改变孔隙和晶体的轴比,研究了微米孔几何尺寸和晶体几何尺寸对硬化水泥浆体第一主应力的影响。模拟结果表明:结晶压力引起的硬化水泥浆体内最大拉应力约为晶体表面结晶压力的3倍;硬化水泥浆体内部最大拉应力主要与孔隙轴比、填充度及结晶压力有关;结晶压力引起拉应力集中是造成硬化水泥浆体破坏的直接原因,NaCl晶体不会先于硬化水泥浆体破坏。Introduction Salt crystallization plays an important role in the physical weathering process of materials,and is generally considered to be one of the main problems affecting the durability of materials,and most of the weathering damage of porous materials is related to salt crystallization.Since the permeation and crystallization of salt solutions are unavoidable.Therefore,it is of great value to explore the crystallization process and mechanism of salt in pores for the study of material durability in the fields of construction engineering,historical building protection engineering,traffic engineering,underground and geotechnical engineering,etc,and is of great significance for improving the disaster prevention and mitigation capabilities of historical buildings and infrastructure,and reasonably predicting the service life of structures.At present,the supersaturated crystallization pressure hypothesis is generally accepted as the cause of salt crystallization failure of porous materials,which holds that the crystallization pressure exerted by crystal on the pore surface is the main cause of the failure of cement-based materials.However,existing study has found that the actual crystallization pressure produced by Na Cl evaporation crystallization is about 0.46 MPa,which is much lower than the tensile strength of concrete,and the concrete material still subjected to damage.Therefore,in this paper,the finite element method is used to study the crystallization process of NaCl in the micro pore of hardened cement paste,and the mechanism of crystallization pressure during the crystallization process is revealed.In addition,the effects of pore and crystal geometry,crystallization pressure and filling degree on the maximum tensile stress inside the hardened cement paste are also discussed.Methods The micro pore model and NaCl crystal model of hardened cement paste are established respectively,and the NaCl crystal model is horizontally put into the micro pore model of hardened cement paste to obtain the NaCl crystallizat

关 键 词：盐结晶 硬化水泥浆体 结晶压力 最大拉应力 

分 类 号：TQ172.1[化学工程—水泥工业]