文献类型：期刊文献

英文题名：Utilizing nano-SiO2 for modifying the microstructure, strength and transport properties of sustainable cementitious materials with waste concrete powder

作者：Wu, Huixia[1,2];Wang, Changqing[3];Yang, Dingyi[4];Ma, Zhiming[4]

机构：[1]Southeast Univ, Sch Mat Sci & Engn, Nanjing 211189, Peoples R China;[2]Shaoxing Univ, Sch Civil Engn, Shaoxing 312000, Peoples R China;[3]Shanghai Univ, Dept Civil Engn, Shanghai 200444, Peoples R China;[4]Yangzhou Univ, Coll Architectural Sci & Engn, Yangzhou 225127, Peoples R China

年份：2023

卷号：63

外文期刊名：JOURNAL OF BUILDING ENGINEERING

收录：SCI-EXPANDED(收录号：WOS:000889753800002)、、EI(收录号：20224713140188)、Scopus(收录号：2-s2.0-85141922222)、WOS

基金：Acknowledgments The authors gratefully acknowledge substantial support of ongoing projects titled National Natural Science Foundation of China (52008364) and Natural Science Foundation of Jiangsu Province (BK20200957) .

语种：英文

外文关键词：Waste concrete powder; Sustainable cementitious materials; Nano-SiO2 modification; Micro-structure; Macro-properties

外文摘要：Using waste concrete powder as an alternative binder in green cementitious materials contributes to reduce the number of construction and demolition waste, and developing an effective method to modify the performance of waste concrete powder blended cementitious materials is necessary. The influences of nano-SiO2 at 0-3% dosage on cementitious materials containing waste concrete powder as partial cement replacement (0-50%), under a ratio of 1:2 for both water-to-binder and binder-to-sand, were investigated in this study with the aspects of micro-structure and macro-performance. The results illustrated that mixing waste concrete powder negatively impacted the hydration reaction and micro-structure of cement paste; however, the mix of nano-SiO2 promoted the secondary hydration reaction and refined pore diameter of waste concrete powder mixed paste. Mixing nano-SiO2 raised the drying shrinkage but reduced the water loss of paste including waste concrete powder. The replacement of cement by waste concrete powder caused the reduction in compressive strength of paste. But at a fixed substitution level of waste concrete powder in paste, the compressive strength rose with the increment of nano-SiO2 content up to 3%. The transport properties rose as waste concrete powder was incorporated in mortar, but the mix of nano-SiO2 significantly reduced the transport properties of waste concrete powder incorpo-rated mortar. Particularly, the effects of nano-SiO2 addition on the decrease in water absorption became more distinct as high content of waste concrete powder was blended. Optimizing the content of waste concrete powder and nano-SiO2 can obtain green cementitious materials owning good strength and low transport properties.