摘要
为了再利用废混凝土,改善玻璃纤维增强混凝土(GRC)的性能,以废混凝土再生骨料(RWCA)取代GRC中的天然砂,以粉煤灰、硅灰取代水泥,分别采用自然老化和50℃加速老化的方法,研究三者单掺和复掺对GRC长期性能的影响.结果表明:用RWCA以30%的质量分数替代GRC中的天然砂,可在一定程度上改善GRC的耐久性,即从骨料角度改善GRC的性能;用粉煤灰以30%的质量分数替代水泥,也可在一定程度上改善GRC的长期性能,但对GRC的早期抗折强度不利;用RWCA以30%的质量分数替代天然砂,同时用粉煤灰以30%的质量分数替代水泥时,不但GRC的早期抗折强度可得到改善,而且对GRC长期抗折强度的提高效果要好于二者单掺时;用RWCA骨料以30%的质量分数替代天然砂,同时用粉煤灰和硅灰分别以20%,10%的质量分数替代水泥,对GRC早期和后期抗折强度均有较大提高,有利于GRC长期抗折强度的保持;X射线衍射(XRD),傅里叶红外光谱(FTIR)及扫描电镜(SEM)分析表明,三者复掺可减少体系中Ca(OH)_2的含量、减小Ca(OH)_2的结晶尺寸,这不但可提高GRC基体的抗折强度,还可减轻玻璃纤维被腐蚀的程度,有利于GRC耐久性的改善.
For the purpose of reusing waste concrete and improving the properties of glass fiber reinforced cement（GRC）,the effects of recycled waste concrete aggregate（RWCA）,fly ash and silica fume,which were either separately mixed or mixed together,on long term durability of GRC was researched using the methods of natural aging and accelerating ageing in 50℃ water.The results show that durability of GRC can be improved to some extent if natural sand of GRC is replaced by 30%（by mass,the same below）of RWCA,namely,the performance of GRC can be improved in terms of aggregate.If cement is replaced by30% of fly ash,its addition is not favorable for the early flexural strength of GRC.If natural sand is replaced by 30% of RWCA,and at the same time,cement is replaced with 30% of fly ash,not only can the early flexural strength but aslo durability of GRC be improved.RWCA and fly ash can be mixed before adding or they can be added separately,the former is better than the latter.The early and late flexural strength of GRC can both be greatly improved if natural sand is replaced by 30% of RWCA,and at the same time the cement is replaced by 20% of fly ash and 10% of silicon fume,which is beneficial to the remaining of long term flexural strength of GRC.Analysis from micro methods（XRD,FTIR and SEM）shows that the three admixtures can all decrease the amount and size of Ca（OH）_2 in the system.This can not only improve the flexural strength of GRC matrix,but also alleviate the erosion of glass fiber,which is favorable to improve the durability of GRC.
作者
程海丽
刘国强
杨飞华
郝利炜
CHENG Haili;LIU Guoqiang;YANG Feihua;HAO Liwei(School of Civil Engineering,North China University of Technology,Beijing 100144,China;Beijing Municipal Road ＆ Bridge Group Co.,Ltd.,Beijing 100068,China;State Key Laboratory of Solid Waste Reuse for Building Materials,Beijing 100041,China)
出处
《建筑材料学报》
EI
CAS
CSCD
北大核心
2018年第3期490-496,510,共8页
Journal of Building Materials
基金
北京市自然科学基金资助项目(2013214)
关键词
废混凝土再生骨料
粉煤灰
硅灰
玻璃纤维增强混凝土
耐久性
recycled waste concrete aggregate（RWCA）
fly ash
silica fume
glass fiber reinforced cement（GRC）
durability
