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On Freeze-Thaw Damage of Concrete Due to Combined Effect of Chloride Penetration and Carbonation

氯离子渗透与碳化联合作用下混凝土冻融损伤研究

基本信息

批准号：
06650500
负责人：
SHOYA Masami
金额：
$ 1.34万
依托单位：
Hachinohe Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650500/
关键词：
Combined action Freezing and thawing action Chloride penetration Carbonation Air content Watar cement ratio

项目摘要

(1) Combined action of freeze-thaw and chloride penetration(1)Chlorides existing in the mortar moved toward inner parts and partially concentrated due to freeze-thaw action and the tendencies were pronounced when a freezing temperature was lower and freeze-thaw cycles increased.(2) The effects of chlorides were serious on the scaling damage and the degree of damages were different in different chloride type, curing condition, water cement ratio and air content.(2) Combined action of freeze-thaw and carbonation(1) Carbonation after freeze-thaw action was accelerated and the degree of carbonation was different in different air content.(2) Weight change due to freeze-thaw action after carbonation increased a little, however, the change of relative dynamic modulus of elasticity was not pronounced.(3) Combined action of freeze-thaw, chroride penetration and carbonation(1) Freeze-thaw action in the presence of chloride affected the rate of carbonation.(2) Scaling damage due to freeze-thaw action in the presence of chloride after carbonation increased, then the mechanism of deterioration was complicated and must be clear in the future.(3) It will be possible to make a synthetic diagnosis of damaged concrete due to combined action of freeze-thaw, chloride penetration and carbonation, through the analyzes concerning the pull-off strength, rebound number or pulse velocity from a side view of strength, and recovering speed or coefficient of water absorption in the rapid test from a side view of tightness.

(1)冻融和氯离子渗透的联合作用（1）由于冻融作用，砂浆中存在的氯离子向内部移动并部分集中，当冻结温度较低和冻融循环次数增加时，这种趋势明显。(2)氯离子对水泥混凝土的结垢破坏影响较大，且不同氯离子种类、养护条件、水灰比和含气量对水泥混凝土的结垢破坏程度不同。(2)冻融与碳化的联合作用（1）冻融作用后碳化加速，不同含气量下碳化程度不同。(2)碳化后冻融作用引起的重量变化略有增加，但相对动弹性模量变化不明显。(3)冻融、氯离子渗透和碳化的共同作用（1）氯离子存在下的冻融作用影响碳化速率。(2)碳酸化后，由于氯离子存在下的冻融作用引起的结垢破坏增加，其劣化机理复杂，有待进一步研究。(3)从强度方面分析混凝土的拔出强度、回弹数或脉冲速度，从密实性方面分析快速试验中的恢复速度或吸水系数，可以对冻融、氯离子渗透和碳化等综合作用下的混凝土损伤进行综合诊断。