复合盐侵蚀再生混凝土耐久性能退化试验研究

硅酸盐通报 ›› 2021, Vol. 40 ›› Issue (11): 3617-3626.

复合盐侵蚀再生混凝土耐久性能退化试验研究

侯泽宇^1,2, 王家滨^1,2, 郭庆军¹, 李恒¹, 张凯峰³

1.西安工业大学建筑工程学院,西安 710021;
2.西安工业大学,西安市军民两用土木工程测试技术与毁损分析重点实验室,西安 710021;
3.中建西部建设北方有限公司,西安 710065

收稿日期:2021-06-09 修回日期:2021-07-21 出版日期:2021-11-15 发布日期:2021-12-08
通讯作者: 王家滨,博士,副教授。E-mail:wangjiabin@xatu.edu.cn
作者简介:侯泽宇(1996—),男,硕士研究生。主要从事混凝土结构耐久性方面的研究。E-mail:1907210564@st.xatu.edu.cn
基金资助:
国家自然科学基金(51908440)

Experimental Study on Durability Degradation of Recycled Aggregate Concrete by Compound Salt Corrosion

HOU Zeyu^1,2, WANG Jiabin^1,2, GUO Qingjun¹, LI Heng¹, ZHANG Kaifeng³

1. School of Civil & Architectural Engineering, Xi'an Technology University, Xi'an 710021, China;
2. Xi'an Key Laboratory of Civil Engineering Testing and Destruction Analysis on Military-Civil Dual Use Technology (XATU), Xi'an Technology University, Xi'an 710021, China;
3. China Construction West Construction North Co., Ltd, Xi'an 710065, China

Received:2021-06-09 Revised:2021-07-21 Online:2021-11-15 Published:2021-12-08

摘要/Abstract

摘要： 我国西北地区土壤及其地下水中含有大量侵蚀性离子,造成了再生混凝土结构耐久性能快速退化,严重制约着再生混凝土在主体结构中的应用。基于西北地区耐久性环境中侵蚀离子组成及区域气候环境特征,以7.5%(质量分数)MgSO₄-7.5%(质量分数)Na₂SO₄-5%(质量分数)NaCl为侵蚀介质,采用干湿交替方式,开展复合盐侵蚀再生混凝土耐久性能退化试验研究。以粉煤灰、矿渣、硅灰、偏高岭土等活性矿物掺合料取代水泥,研究矿物掺合料搭配方式对再生混凝土耐久性能影响。采用XRD、FTIR、TG-DSC及SEM、EDS等表征手段,分析侵蚀产物矿物组成、含量及微结构变化,研究复合盐侵蚀再生混凝土损伤过程。随着干湿交替次数增加,再生混凝土相对动弹性模量、质量变化率、相对抗压强度、相对劈裂抗拉强度及损伤层厚度的变化规律与矿物掺合料搭配方式有着显著的相关性。随着侵蚀离子的不断扩散,混凝土碱度降低,在表面依次形成了以水镁石、石膏及钙钒石为主要产物的致密侵蚀产物层,短暂阻碍了侵蚀离子进一步扩散。随着侵蚀产物不断堆积及无胶凝性水化硅酸镁的形成,在膨胀应力及盐结晶压力共同作用下,再生混凝土表面大量剥蚀并开裂,耐久性能快速退化。

关键词: 再生混凝土, 耐久性能, 复合盐侵蚀, 干湿交替, 矿物掺合料, 退化机理

Abstract: There are a great number of corrosion ions in the soil and groundwater of Northwest China, which causing rapid degradation of durability of recycled aggregate concrete structures severely limit the application of recycled aggregate concrete in modern concrete structures. Based on the composition of corrosive ions and the characteristics of regional climate and environment in the durability environment of Northwest China, the experiment of durability degradation of recycled aggregate concrete subjected to compound salts was carried out by dry-wet cycles method with 7.5% (mass fraction) MgSO₄-7.5% (mass fraction) Na₂SO₄-5% (mass fraction) NaCl as the corrosive medium. The effects of mineral admixtures on durability of recycled aggregate concrete were studied by using active mineral admixtures such as fly ash, slag, silica fume and metakaolin instead of cement. And then, the mineral composition and relative content of mineral phases, and microstructures of corrosion products were characterized by XRD, FTIR, TG-DSC, SEM and EDS, respectively. In addition, the durability degradation process of recycled aggregate concrete was suggested. As the dry-wet cycles increase, the relative dynamic elastic modulus, mass change rate, relative compressive strength, relative splitting tensile strength, and damage depth are significantly related to the collocation of mineral admixtures. With the corrosion ions diffusing into concrete, the alkalinity of concrete decreases and the dense corrosion layers with brucite, gypsum and ettringite as the mainly corrosion products are successively formed on the surface of concrete, which temporarily hinders the further diffusion of corrosion ions. With the continuous accumulation of corrosion products and the formation of non-gelling products, the surface of recycled aggregate concrete is spalled and cracked under the combined action of expansion stress and salt crystallization pressure. The durability of recycled aggregate concrete is rapidly degraded.

Key words: recycled aggregate concrete, durability, compound salt corrosion, dry-wet cycle, mineral admixture, degradation mechanism

中图分类号:

TU528.44

侯泽宇, 王家滨, 郭庆军, 李恒, 张凯峰. 复合盐侵蚀再生混凝土耐久性能退化试验研究[J]. 硅酸盐通报, 2021, 40(11): 3617-3626.

HOU Zeyu, WANG Jiabin, GUO Qingjun, LI Heng, ZHANG Kaifeng. Experimental Study on Durability Degradation of Recycled Aggregate Concrete by Compound Salt Corrosion[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(11): 3617-3626.

参考文献

[1] 余红发.盐湖地区高性能混凝土的耐久性、机理与使用寿命预测方法[D].南京:东南大学,2004.
YU H F. Study on high performance concrete in salt lake: durability, mechanism and service life prediction[D]. Nanjing: Southeast University, 2004 (in Chinese).
[2] 王海龙,董宜森,孙晓燕,等.干湿交替环境下混凝土受硫酸盐侵蚀劣化机理[J].浙江大学学报(工学版),2012,46(7):1255-1261.
WANG H L, DONG Y S, SUN X Y, et al. Damage mechanism of concrete deteriorated by sulfate attack in wet-dry cycle environment[J]. Journal of Zhejiang University (Engineering Science), 2012, 46(7): 1255-1261 (in Chinese).
[3] 梁咏宁,袁迎曙.硫酸钠和硫酸镁溶液中混凝土腐蚀破坏的机理[J].硅酸盐学报,2007,35(4):504-508.
LIANG Y N, YUAN Y S. Mechanism of concrete destruction under sodium sulfate and magnesium sulfate solution[J]. Journal of the Chinese Ceramic Society, 2007, 35(4): 504-508 (in Chinese).
[4] 金祖权,孙伟,张云升,等.混凝土在硫酸盐、氯盐溶液中的损伤过程[J].硅酸盐学报,2006,34(5):630-635.
JIN Z Q, SUN W, ZHANG Y S, et al. Damage of concrete in sulfate and chloride solution[J]. Journal of the Chinese Ceramic Society, 2006, 34(5): 630-635 (in Chinese).
[5] 刘加平,刘玉静,石亮,等.氯盐-硫酸盐对水泥基材料的复合侵蚀破坏[J].建筑材料学报,2016,19(6):993-997.
LIU J P, LIU Y J, SHI L, et al. Combined attack of chloride-sulfate on cement-based materials[J]. Journal of Building Materials, 2016, 19(6): 993-997 (in Chinese).
[6] HE R, ZHENG S N, GAN V J L, et al. Damage mechanism and interfacial transition zone characteristics of concrete under sulfate erosion and dry-wet cycles[J]. Construction and Building Materials, 2020, 255: 119340.
[7] XIAO J Z, LI W G, FAN Y H, et al. An overview of study on recycled aggregate concrete in China (1996—2011)[J]. Construction and Building Materials, 2012, 31: 364-383.
[8] 李恒,郭庆军,王家滨,等.再生混凝土界面结构及耐久性综述[J].材料导报,2020,34(13):13050-13057.
LI H, GUO Q J, WANG J B, et al. Meso-/micro-structure of interfacial transition zone and durability of recycled aggregate concrete: a review[J]. Materials Reports, 2020, 34(13): 13050-13057 (in Chinese).
[9] ZHANG H R, JI T, LIU H. Performance evolution of the interfacial transition zone (ITZ) in recycled aggregate concrete under external sulfate attacks and dry-wet cycling[J]. Construction and Building Materials, 2019, 229: 116938.
[10] XIE F, LI J P, ZHAO G W, et al. Experimental study on performance of cast-in-situ recycled aggregate concrete under different sulfate attack exposures[J]. Construction and Building Materials, 2020, 253: 119144.
[11] 刘大庆,陈亮亮,王生云,等.再生混凝土在硫酸盐与干湿循环耦合作用下的耐久性能研究[J].长江科学院院报,2018,35(10):137-142.
LIU D Q, CHEN L L, WANG S Y, et al. Durability and life prediction of recycled concrete under sulfate attack and wet-dry cycle[J]. Journal of Yangtze River Scientific Research Institute, 2018, 35(10): 137-142 (in Chinese).
[12] QI B, GAO J M, CHEN F, et al. Evaluation of the damage process of recycled aggregate concrete under sulfate attack and wetting-drying cycles[J]. Construction and Building Materials, 2017, 138: 254-262.
[13] P·库马尔·梅塔,保罗·J·M·蒙蒂罗.混凝土微观结构、性能和材料[M].欧阳东译.北京:中国建筑工业出版社,2016:5.
MEHTA P K, MONTEIRO P J M. Concrete: microstructure, properties, and materials[M]. OUYANG D tral. Beijing: China Architecture & Building Press, 2016: 5 (in Chinese).
[14] MARDANI-AGHABAGLOU A, DE NAN SEZER G, RAMYAR K. Comparison of fly ash, silica fume and metakaolin from mechanical properties and durability performance of mortar mixtures view point[J]. Construction and Building Materials, 2014, 70: 17-25.
[15] 王家滨,牛荻涛.盐湖卤水侵蚀喷射混凝土衬砌耐久性能退化规律研究[J].硅酸盐通报,2019,38(1):33-40.
WANG J B, NIU D T. Research on durability performance deterioration rules of brine-exposed shotcrete in salt lake environment[J]. Bulletin of the Chinese Ceramic Society, 2019, 38(1): 33-40 (in Chinese).
[16] 王家滨,牛荻涛,何晖,等.复合盐侵蚀衬砌喷射混凝土耐久性退化研究[J].土木工程学报,2019,52(9):79-90.
WANG J B, NIU D T, HE H, et al. Durability degradation of lining shotcrete exposed to compound salt[J]. China Civil Engineering Journal, 2019, 52(9): 79-90 (in Chinese).