基于复合盐溶液浓度的再生骨料混凝土抗冻性能试验研究

Frost Resistance of Recycled Aggregate Concrete Based on Compound Salt Solution Concentration

为探究不同浓度复合盐溶液对再生骨料混凝土(Recycled Aggregate Concrete,RAC)抗冻性影响,以复合盐浓度、强度等级和冻融循环次数为变量,对RAC进行冻融循环试验,并分析其表观损伤程度、质量损失率、劈裂抗拉损失率、立方体抗压强度损失率和相对动弹性模量损失率。结果表明:RAC的强度等级越高,抵抗盐冻破坏能力越强;30次盐冻循环后,RAC的质量损失率、抗压强度损失率、劈裂抗拉损失率和相对动弹性模量损失率均随复合盐溶液浓度提高而减小;90次盐冻循环后,RAC的盐冻损伤则随复合盐溶液浓度提高而增大。以复合盐浓度和强度等级为参数建立了指数函数盐冻损伤模型和Weibull分布函数盐冻损伤模型。对比后发现Weibull分布函数盐冻损伤模型衍生的生存函数图和失效率函数图能更直观地反映盐冻损伤程度及损伤效率,且模型与其他学者试验结果均吻合良好。

In the aim of assessing the impact of different compound salt solution concentrations on the frost resistance of recycled aggregate concrete(RAC),we conducted freeze-thaw cycle tests on RAC samples by varying the concentration of the compound salt solution,the strength grades,and the number of freeze-thaw cycles.We scrutinized apparent damage,mass loss rate,splitting tensile strength loss rate,cubic compressive strength loss rate,and relative dynamic elastic modulus loss rate.Our findings reveal that higher strength grades correlate with better salt-frost resistance in RAC.After 30 cycles,mass loss,compressive strength and splitting and tensile strength loss,as well as relative dynamic elastic modulus loss decrease with increasing concentration of compound salt solution.However,after 90 cycles,salt-frost damage escalates with rising solution concentration.We established exponential function and Weibull distribution salt-frost damage models for RAC in consideration of the solution concentration and strength grades.Comparison manifests that the survival function graph and failure rate fuction rendered from Weibull distribution model better describe the salt frost damage level and efficiency.Moreover,the Weibull distribution model result aligns well with experimental results from other scholars.