卤水长期浸泡下高延性混凝土力学性能试验及强度衰减模型研究

Experimental research on mechanical properties and compressive strength attenuation model of HDC after long-term in brine immersion

采用4种不同溶液(0%Cl^(-1)+0%SO_(4)^(2-)、5%Cl^(-1)+5%SO_(4)^(2-)、5%Cl^(-1)+10%SO_(4)^(2-)、10%Cl^(-1)+5%SO_(4)^(2-))对高延性混凝土(HDC)立方体试块进行卤水长期浸泡试验,得出在浸泡时间和卤水浓度不同时HDC基本力学性能的变化规律。试验结果表明,在4种不同卤水环境下,HDC强度和质量变化规律差异较大。其中,强度从开始浸泡到90 d期间,4种不同溶液中,(5%Cl^(-1)+10%SO_(4)^(2-))环境下HDC强度降低率最高达15.3%,表明SO_(4)^(2-)浓度的提高,加快了HDC的侵蚀。在溶液(10%Cl^(-1)+5%SO_(4)^(2-))中HDC强度损失率在360 d时达到11.90%,最终360 d浸泡结束时不同卤水浓度强度损失率(10%Cl^(-1)+5%SO_(4)^(2-))>(5%Cl^(-1)+10%SO_(4)^(2-))>(5%Cl^(-1)+5%SO_(4)^(2-))。30 d时溶液(5%Cl^(-1)+5%SO_(4)^(2-))中的HDC质量出现增加,浸泡至210 d时溶液(5%Cl^(-1)+10%SO_(4)^(2-))中的质量损失率达到-0.6%,直至试验结束一直处于质量增加状态,溶液(10%Cl^(-1)+5%SO_(4)^(2-))中的质量损失率在浸泡270 d时最大达到-1.1%,且整个试验阶段质量几乎一直是增加的。从HDC浸泡至360 d时质量损失率的变化情况,可以得出溶液对其质量损失率即影响程度上:(10%Cl^(-1)+5%SO_(4)^(2-))>(5%Cl^(-1)+10%SO_(4)^(2-))>(0%Cl^(-1)+0%SO_(4)^(2-))>(5%Cl^(-1)+5%SO_(4)^(2-))。最后,通过HDC在不同溶液下与清水组抗压强度对比变化得到不同卤水下HDC抗压强度衰减模型和损伤破坏准则。

The long-term immersion test of HDC cubic specimens was conducted in 4 different solutions(0%Cl^(-1)+0%SO_(4)^(2-),5%Cl^(-1)+5%SO_(4)^(2-),5%Cl^(-1)+10%SO_(4)^(2-),10%Cl^(-1)+5%SO_(4)^(2-)),and the law of changed of HDCbasic mechanical properties with different immersion times and brine concentrations was obtained.The test resultsshowed that the change laws of HDC strength and mass varies greatly with different immersion times in the 4 brinedifferent environments.In terms of HDC strength,during the period from the beginning of immersion to the 90 d,the reduction rate of HDC strength was the highest(up to 15.3%)in the 5%Cl^(-1)+10%SO_(4)^(2-)environment,indicatingthat the increase in the concentration of SO_(4)^(2-)accelerated the erosion of HDC concrete.However,in the last day ofimmersion the reduction rate of the concrete strength in(10%Cl^(-1)+5%SO_(4)^(2-))solution is the highest 11.90%,fol-lowed by the reduction rate in(5%Cl^(-1)+10%SO_(4)^(2-))solution,and the reduction rate in(5%Cl^(-1)+5%SO_(4)^(2-)~2)solutionwas the lowest.At 30 d,the HDC mass in the solution(5%Cl-+5%SO_(4)^(2-))increased.In the 210 d,the mass lossrate of HDC in(5%Cl^(-1)+10%SO_(4)^(2-))solution,reached-0.6%,and the mass keeped increasing till the end of thetest.In the 270 d of immersion,the mass loss rate in(10%Cl^(-1)+5%SO_(4)^(2-))reached the highest-1.1%,and themass has almost always been in a relative increase.The variation of the mass loss rate of HDC from the beginning ofimmersio;n to the 360 d showed that the degree of solution influe;nce on the mass loss rate followed the sequence:(10%Cl+5%SO_(4)^(2-))>(5%Cl^(-1)+10%SO_(4)^(2-))>(0%Cl^(-1)+0%SO_(4)^(2-)~2)>(5%Cl^(-1)+5%SO_(4)^(2-)).Finally,the HDC com-pressive strength attenuation model and damage failure criterion of different brines were obtained by comparing thecompressive strength of HDC with different water solutions under different solutions.