摘要
科学把握再生块体/骨料混凝土的耐久性能,是促进该类混凝土工程应用的基础前提。为揭示再生块体/骨料混凝土中石子-砂浆界面、新砂浆-旧砂浆界面的碳化性能,开展了这2类界面以及砂浆基体的快速碳化对比试验,并对新砂浆-旧砂浆界面及其附近的孔隙率进行了背散射电子图像分析。研究发现:无论是石片-砂浆试件还是砂浆-砂浆试件,界面处的碳化深度都大于砂浆基体,且越靠近界面的部位碳化程度也相对越大,呈现出较明显的二维碳化叠加现象;石片-砂浆试件的界面碳化深度为26~46 mm,而砂浆-砂浆试件的界面碳化深度仅为7~15 mm,即与新砂浆-旧砂浆界面相比,石子-砂浆界面的碳化深度明显更大,是抗碳化能力更弱的一类界面;新砂浆的水灰比对新砂浆-旧砂浆界面的碳化性能影响较大,相关的碳化深度降幅介于15%~52%之间,而旧砂浆水灰比对该类界面的碳化性能影响不明显;新砂浆水灰比一定时,新砂浆-旧砂浆界面的孔隙率随着旧砂浆水灰比的改变几乎没有变化,而旧砂浆水灰比一定时,该类界面的孔隙率随着新砂浆水灰比的减小明显降低。实际工程中,通过控制新砂浆的水灰比,可有效改善新砂浆-旧砂浆界面的抗碳化性能。
Scientifically grasping the durability performance of the recycled lump/aggregate concrete(RLAC)is of great significance for promoting the engineering application of this type of concrete.In this paper,to reveal the carbonation properties of the stone-mortar interface and the new mortar-old mortar interface in RLAC,rapid carbonation tests of these two kinds of interfaces and the mortar matrix were carried out,and the porosity of the new mortar-old mortar interfacial transition zone was investigated through backscatter electron images.The results show that the carbonization depth of the interfacial transition zone is greater than that of the mortar matrix,and the closer to the interface,the greater the degree of carbonization,showing an obvious two-dimension carbonization superposition phenomenon.The interface carbonization depths of the stone-mortar specimens vary from 26 to 46 mm,while those of the mortar-mortar specimens are only 7~15 mm.As compared with the new mortar-old mortar interface,the carbonization depth of the stone-mortar interface is much greater,indicating the latter interface having a weaker carbonization resistance.The water-to-cement ratio of the new mortar has a great influence on the carbonation performance of the new mortar-old mortar interface,and the related reduction in carbonization depth is between 15%and 52%,while the water-to-cement ratio of the old mortar has no obvious effect on the carbonation performance of such interface.When the water-to-cement ratio of the new mortar is fixed,the porosity of the new mortar-old mortar interface is almost unchanged with the water-to-cement ratio of the old mortar.However,when the water-to-cement ratio of the old mortar is fixed,the porosity of such interface decreases greatly with the reducing of the water-to-cement ratio of the new mortar.There thus comes to the conclusion that,in practical engineering,the carbonation performance of the new mortar-old mortar interface can be effectively improved by controlling the water-to-cement ratio of the new mortar.
作者
吴波
黄婷婷
WU Bo;HUANG Tingting(State Key Laboratory of Subtropical Building Science,South China University of Technology,Guangzhou 510640,Guangdong,China)
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2023年第7期52-60,共9页
Journal of South China University of Technology(Natural Science Edition)
基金
广东省重点领域研发计划项目(2019B111107003)
国家自然科学基金资助项目(52078219)
广东省现代土木工程技术重点实验室资助项目(2021B1212040003)。
关键词
再生块体/骨料混凝土
界面
碳化性能
孔隙特征
recycled lump/aggregate concrete
interface
carbonation property
pore characteristic
作者简介
吴波(1968-),男,博士,研究员,主要从事建筑固废再生利用与结构抗灾研究。E-mail:bowu@scut.edu.cn。
