酸雨侵蚀下废瓷砖再生混凝土中性化性能研究
发布时间：2019-01-26 12:32
【摘要】：混凝土材料的大量消耗导致天然砂石资源短缺,而由工业污染形成的酸雨致使混凝土构筑物耐久性显著下降。针对上述问题,本文主要以废瓷砖为再生粗细骨料、以废瓷砖粉为掺合料,制备新型绿色再生混凝土。根据湖南省酸雨的特点,进行室内模拟酸雨溶液干湿循环试验,研究酸雨侵蚀对再生混凝土中性化深度的影响,并将之与室外暴露一年的实测数据相比较。通过测试分析不同侵蚀环境条件下混凝土的外观侵蚀、质量变化率、抗压强度、相对动弹性模量以及中性化深度等指标,探讨再生骨料对混凝土抗酸雨侵蚀能力的影响,并从微观角度分析其侵蚀机理。研究结果表明:在室外暴露试验中,与原生碎石混凝土相比,未掺废瓷砖粉掺合料的废瓷砖再生骨料混凝土的质量损失率略大,但其抗压强度较高,而掺有废瓷砖粉的废瓷砖再生混凝土,其质量损失率更大,抗压强度较低。在模拟酸雨溶液侵蚀条件下,与原生碎石混凝土相比,未掺废瓷砖粉掺合料的废瓷砖再生粗骨料混凝土的抗压强度较高,质量变化率较小,经酸雨侵蚀后的中性化深度最小,表明废瓷砖再生粗骨料混凝土的抗侵蚀能力优于原生碎石混凝土;而掺入废瓷砖粉的再生混凝土抗压强度随废瓷砖粉掺量的增加而降低,中性化深度随废瓷粉掺量的增加而增大,建议废瓷砖粉掺量控制在20%以内为宜。废瓷砖再生混凝土中性化深度随p H值的降低而增大。在侵蚀早期,p H值大小对混凝土受酸雨侵蚀程度影响较小;但在侵蚀后期,随p H值降低,混凝土受酸雨侵蚀加剧。与标准养护环境相比,在室内模拟酸雨侵蚀下再生混凝土的化学结合水含量较低,且废瓷砖再生混凝土的化学结合水含量随废瓷砖粉掺量的增加而降低。在相同酸雨侵蚀条件下,混凝土表层碱度降低,水化产物分解引起表层脱落;随侵蚀程度加深,混凝土内部生成大量石膏晶体,造成体积膨胀引起开裂。与原生碎石混凝土相比,废瓷砖再生混凝土的化学结合水含量较低,内部显微结构更致密。
[Abstract]:The large consumption of concrete materials leads to the shortage of natural sand and stone resources, while the acid rain caused by industrial pollution significantly decreases the durability of concrete structures. In order to solve the above problems, a new type of green recycled concrete was prepared by using waste ceramic tile as recycled coarse aggregate and waste ceramic tile powder as admixture. According to the characteristics of acid rain in Hunan province, the dry and wet cycle tests of simulated acid rain solution were carried out in laboratory to study the effect of acid rain erosion on the neutralization depth of recycled concrete, and compared it with the measured data of outdoor exposure for one year. The influence of recycled aggregate on the corrosion resistance of concrete to acid rain is discussed by testing and analyzing the indexes of concrete under different erosion environment, such as appearance erosion, quality change rate, compressive strength, relative dynamic modulus of elasticity and neutralization depth. The erosion mechanism is analyzed from the microscopic point of view. The results show that in outdoor exposure test, the mass loss rate of recycled aggregate concrete without waste ceramic tile powder admixture is slightly larger than that of primary crushed stone concrete, but its compressive strength is higher. The mass loss rate and compressive strength of recycled concrete with waste ceramic tile powder are higher and lower. Under the condition of simulated acid rain solution erosion, the recycled coarse aggregate concrete without waste ceramic tile powder has higher compressive strength, lower quality change rate and the smallest neutralization depth after acid rain erosion, compared with the original crushed stone concrete. The results show that the anti-erosion ability of recycled coarse aggregate concrete of waste ceramic tile is better than that of original crushed stone concrete. However, the compressive strength of recycled concrete mixed with waste ceramic tile powder decreases with the increase of waste ceramic tile powder content, and the neutralization depth increases with the increase of waste ceramic powder content. It is suggested that the content of waste ceramic tile powder should be controlled within 20%. The neutralization depth of recycled concrete increases with the decrease of pH value. At the early stage of erosion, the value of, p H has little effect on the degree of acid rain erosion of concrete, but at the late stage of erosion, with the decrease of pH value, the corrosion of concrete is aggravated by acid rain. Compared with the standard curing environment, the chemical binding water content of recycled concrete under simulated acid rain is lower, and the chemical binding water content of recycled concrete decreases with the increase of waste ceramic tile powder content. Under the same condition of acid rain erosion, the alkalinity of the surface layer of concrete decreases, the decomposition of hydration products results in shedding of the surface layer, and with the deepening of the erosion degree, a large number of gypsum crystals are formed in the concrete, resulting in volume expansion and cracking. Compared with primary crushed stone concrete, recycled concrete of waste ceramic tile has lower water content and denser microstructure.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU528
本文编号：2415485
[Abstract]:The large consumption of concrete materials leads to the shortage of natural sand and stone resources, while the acid rain caused by industrial pollution significantly decreases the durability of concrete structures. In order to solve the above problems, a new type of green recycled concrete was prepared by using waste ceramic tile as recycled coarse aggregate and waste ceramic tile powder as admixture. According to the characteristics of acid rain in Hunan province, the dry and wet cycle tests of simulated acid rain solution were carried out in laboratory to study the effect of acid rain erosion on the neutralization depth of recycled concrete, and compared it with the measured data of outdoor exposure for one year. The influence of recycled aggregate on the corrosion resistance of concrete to acid rain is discussed by testing and analyzing the indexes of concrete under different erosion environment, such as appearance erosion, quality change rate, compressive strength, relative dynamic modulus of elasticity and neutralization depth. The erosion mechanism is analyzed from the microscopic point of view. The results show that in outdoor exposure test, the mass loss rate of recycled aggregate concrete without waste ceramic tile powder admixture is slightly larger than that of primary crushed stone concrete, but its compressive strength is higher. The mass loss rate and compressive strength of recycled concrete with waste ceramic tile powder are higher and lower. Under the condition of simulated acid rain solution erosion, the recycled coarse aggregate concrete without waste ceramic tile powder has higher compressive strength, lower quality change rate and the smallest neutralization depth after acid rain erosion, compared with the original crushed stone concrete. The results show that the anti-erosion ability of recycled coarse aggregate concrete of waste ceramic tile is better than that of original crushed stone concrete. However, the compressive strength of recycled concrete mixed with waste ceramic tile powder decreases with the increase of waste ceramic tile powder content, and the neutralization depth increases with the increase of waste ceramic powder content. It is suggested that the content of waste ceramic tile powder should be controlled within 20%. The neutralization depth of recycled concrete increases with the decrease of pH value. At the early stage of erosion, the value of, p H has little effect on the degree of acid rain erosion of concrete, but at the late stage of erosion, with the decrease of pH value, the corrosion of concrete is aggravated by acid rain. Compared with the standard curing environment, the chemical binding water content of recycled concrete under simulated acid rain is lower, and the chemical binding water content of recycled concrete decreases with the increase of waste ceramic tile powder content. Under the same condition of acid rain erosion, the alkalinity of the surface layer of concrete decreases, the decomposition of hydration products results in shedding of the surface layer, and with the deepening of the erosion degree, a large number of gypsum crystals are formed in the concrete, resulting in volume expansion and cracking. Compared with primary crushed stone concrete, recycled concrete of waste ceramic tile has lower water content and denser microstructure.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU528
【参考文献】
相关期刊论文 前10条
1 唐小林;王劲松;薛文韬;商旭升;张金勇;;湖南省中部地区酸雨对混凝土耐久性的影响[J];南华大学学报(自然科学版);2014年04期
2 许文杰;巴太斌;李蕾蕾;张伟超;;机制砂石生产线的规范化设计[J];河南建材;2013年04期
3 雍定红;;对混凝土强度检验方法的分析[J];城市建筑;2013年10期
4 陈梦成;丁小蒙;王凯;谢力;;废建筑陶瓷再生混凝土研究现状与热点问题分析[J];材料导报;2012年S2期
5 许新辉;郜洪文;;中国南方酸雨的分布特征及其成因分析[J];四川环境;2011年04期
6 李年维;;硫酸盐侵蚀中钙矾石的形成机理及硫酸盐侵蚀预防措施[J];水利与建筑工程学报;2011年04期
7 肖建庄;刘琼;李文贵;Vivian Tam;;再生混凝土细微观结构和破坏机理研究[J];青岛理工大学学报;2009年04期
8 牛荻涛;周浩爽;牛建刚;;承载混凝土酸雨侵蚀中性化试验研究[J];硅酸盐通报;2009年03期
9 成丕富;刘海涛;李方方;王怀岭;叶沛;;水灰比和孔隙率对砂浆抗酸雨腐蚀性能的影响[J];混凝土;2008年11期
10 张晓勇;王振红;;当前酸雨形势和治理对策[J];环境科学与管理;2007年08期
，本文编号：2415485
本文链接：https://www.wllwen.com/guanlilunwen/chengjian/2415485.html
