Study on deterioration of concrete subjected to sulfate attack in cold regions and its countermeasures

寒冷地区混凝土硫酸盐侵蚀劣化及对策研究

• 批准号: 13450178
• 负责人: MIURA Takashi
• 金额: $ 5.82万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450178/
• 关键词: Concrete; Combined deterioration; Frost damage; sulfate; Sulfuric acid; Sea water; Prediction of deterioration; Soaking test; 中性化深さ; 侵食深さ; モルタル; 塩化ナトリウム; モルタル侵漬試験; 硫酸濃度

In this study, the deterioration of concrete structures exposed to sulfuric acid, sulfate, and chloride were researched. Additionally the patterns with the combined deterioration between these factors and freeze/thaw attack and its mechanism were investigated. From these experiments, the following conclusions were drawn.The testing results of soaking mortar and concrete specimens in sulfuric acid solution revealed that the deterioration of concrete is more accelerated with low water-cement ratio compared to high water-cement ratio. Further it was indicated that the deterioration rate of concrete by sulfuric acid was predicted as a function of water-cement ratio, sulfuric acid concentration, and the period of soaking in sulfuric acid.From the testing results with the combined deterioration between seawater and freeze/thaw attack, it was recognized that the influence of sodium chloride in seawater on the deterioration is remarkably more than that of magnesium sulfate and the deterioration pattern is mainly governed by scaling from the concrete surface. On the other hand, it was confirmed that the combined deterioration between sulfuric acid and freeze/thaw attack induces remarkable scaling and the mass loss caused by scaling increases as water-cement ratio and sulfuric acid concentration increase. Further it was shown that this type of combined deterioration could be evaluated by superimposing the deterioration curves by the sulfuric acid attack considering the scaling rate at low temperatures and freeze/thaw attack.Finally it was recognized that the internal evaluated strength distribution of concrete by needle penetration testing method includes much variation depending on the deterioration pattern and this testing method is not always suitable for evaluating concrete strength.

在这项研究中，混凝土结构暴露于硫酸，硫酸盐和氯化物的劣化进行了研究。此外，还研究了这些因素与冻融侵蚀的复合劣化模式及其机理。通过对砂浆和混凝土试件在硫酸溶液中的浸泡试验，发现低水灰比混凝土的劣化比高水灰比混凝土的劣化更快。根据海水和冻融侵蚀共同作用下混凝土的试验结果，预测了混凝土的硫酸劣化速率与水灰比、硫酸浓度和浸泡时间的关系。海水中氯化钠对腐蚀的影响明显大于硫酸镁，劣化模式主要由混凝土表面的剥落控制。另一方面，它被证实，硫酸和冻融侵蚀之间的联合劣化引起显着的结垢和由结垢引起的质量损失增加的水灰比和硫酸浓度的增加。此外，还表明，考虑到低温和冷冻条件下的结垢率，可通过叠加硫酸侵蚀的劣化曲线来评估这种类型的组合劣化。最后指出，用针入法测定混凝土内部强度分布时，由于混凝土的劣化形式不同，其内部强度分布有很大的变化，这种试验方法并不总是适用于评价混凝土内部强度分布混凝土强度

项目成果

Alexandru Lechkun, 板橋洋房, 三浦尚: "Sulfuric acid attack on concrete at various temperatures"土木学会東北支部技術研究発表会(平成15年度)講演概要集. 598-599 (2004)

Alexandru Lechkun、Hirofusa Itabashi、Takashi Miura：“不同温度下的硫酸对混凝土的侵蚀”日本土木工程师学会东北分会技术研究会议摘要集（2003 年）598-599（2004 年）。

青柳直樹: "硫酸環境下におけるコンクリートの劣化性状と内部強度分布に関する研究"コンクリート工学論文集. 15・1. 35-43 (2004)

青柳直树：“硫酸环境下混凝土的劣化特性和内部强度分布的研究”《混凝土工程杂志》15・1（2004）。

吉田祐介: "硫酸によるコンクリートの劣化に及ぼす粗骨材量の影響"平成15年度土木学会東北支部技術研究発表会講演概要集. 600-601 (2004)

Yusuke Yoshida：“粗骨料用量对硫酸引起的混凝土劣化的影响”2003年日本土木学会东北分会技术研究报告摘要600-601（2004年）。

青柳 直樹: "硫酸環境にさらされたコンクリートの劣化状態に関する研究"平成13年度東北支部技術研究発表会講演概要. (印刷中). (2002)

Naoki Aoyagi：“暴露于硫酸环境下的混凝土的劣化状态的研究”2001 年东北分部技术研究报告摘要（2002 年出版）。

板橋洋房, 三浦尚: "硫酸塩の影響を受けるコンクリートの凍害に関する基礎的研究"セメント・コンクリート論文集. 56. 437-442 (2003)

Hirofusa Itabashi、Takashi Miura：“受硫酸盐影响的混凝土冻结损伤的基础研究”《水泥和混凝土论文》56. 437-442 (2003)。