中国粉体技术2025，Vol.31Issue(5)：135-144,10.DOI:10.13732/j.issn.1008-5548.2025.05.011
碳化处理对再生骨料性能的影响
Effect of carbonation treatment on properties of recycled concrete aggregates
摘要
Abstract
Objective This study investigates the property changes in recycled concrete aggregates(RCA)before and after carbonation treat-ment,focusing on the reinforcement mechanisms that carbonation exerts on both macro-properties and microstructural character-istics through multi-scale analysis.The correlation between carbonation processes and property enhancement in RCAs was estab-lished for the first time,aiming to enhance the resource utilization efficiency of construction waste while contributing to carbon sequestration and emission reduction.The findings provide valuable theoretical support for advancing low-carbon recycling tech-nologies in the construction sector,aligning with the"carbon peak and carbon neutrality"goals. Methods In this study,RCA were crushed and sieved into three categories of particle size(5～10 mm,10～20 mm,and 20～26 mm).The aggregates underwent pre-wetting treatments of 0,1,12,and 24 hours before being subjected to carbonation under controlled conditions(20％CO2 concentration and 0.4 MPa pressure)for 6 hours.The effect of pre-wetting duration on carbonation efficiency was analyzed,and further investigations were conducted based on the identified optimal pre-wetting dura-tion(1 hour)to examine the variations in mass growth rate for the three particle sizes after carbonation durations of 6,12,and 24 hours.A comparative analysis was performed to evaluate the effects of different carbonation durations on key physical proper-ties,including apparent density,water absorption,crushing value,and microstructural characteristics of the aggregates. Results and Discussion The carbonation treatment showed optimal properties after a 1-hour pre-wetting,with the 5～10 mm fraction demonstrating enhanced reinforcement due to its higher specific surface area.Under the controlled carbonation condi-tions(20％CO2 concentration and 0.4 MPa pressure),the 5～10 mm aggregates exhibited a 3.34％increase in apparent density(2.430～2.512 g·cm-3),a 28.42％reduction in water absorption(4.12％～2.95％),and a 13.36％decrease in crushing value(18.7％～16.2％)after 6 hours of carbonation.The CaCO3 mass loss was 18.16％,which was attributed to the crystalline phase transformation detected through XRD analysis and corresponded to a carbon sequestration efficiency of 41.27％,approximately 2.29 times higher than the non-carbonated control group(12.57％).In contrast,the large aggregates(20～26 mm)displayed a carbon sequestration efficiency of only 32.02％,which was 22.41％lower than the smaller aggregates.This size-dependent dif-ference originated from variations in CO2 diffusion kinetics,where the smaller aggregates,with their shorter gas transport paths,allowed for more complete carbonation reactions. Conclusion Carbonation treatment results in the formation of dense calcium carbonate crystals on the surface of RCA,filling the pores within the aggregates,thereby increasing apparent density and reducing both water absorption rate and crushing value.Factors such as pre-wetting duration,carbonation time,and particle size significantly affect the carbonation efficiency.A shorter pre-wetting duration and longer carbonation time lead to optimal properties in smaller particle size aggregates.关键词
碳化/再生骨料/吸水率/压碎值/碳酸钙Key words
carbonation/recycled concrete aggregate/water absorption rate/crushing value/calcium carbonate分类
建筑与水利引用本文复制引用
房延凤,何晨光,赵明宇,李博鑫..碳化处理对再生骨料性能的影响[J].中国粉体技术,2025,31(5):135-144,10.基金项目
国家自然科学基金项目,编号:52378252、52278262 （）
辽宁省"兴辽英才"青年拔尖人才项目,编号:XLYC2403149. （）
