硅酸盐学报2025，Vol.53Issue(5)：1313-1327,15.DOI:10.14062/j.issn.0454-5648.20240489
碳化废弃混凝土微粉的特性及作辅助性胶凝材料的研究进展
Properties of Carbonated Waste Concrete Powder and Its Use as Supplementary Cementitious Materials:A Review
摘要
Abstract
As an energy-intensive industry,cement manufacturing is a significant contributor to CO2 emissions.Simultaneously,the increasing volume of construction waste has also exerted significant pressure on the environment.Recycling demolished concrete has been proposed as a strategy to address the depletion of aggregate resources.In addition,it facilitates the disposal of construction waste and reduce carbon emissions.A particularly promising approach is the recycling of waste concrete powders(WCP)as a supplementary cementitious material(SCM),which has garnered significant attention.However,the high absorption and low reactivity of WCP pose a challenge to its direct use as SCM.Accelerated carbonation of WCP produces calcium carbonate(CaCO3)and amorphous silica gel.These products enhance the reactivity of WCP and facilitate the effective sequestration of CO2.This process not only promotes the high-quality utilization of WCP but also helps to mitigate the environmental and energy burdens associated with cement production. This study reviews the properties of carbonated waste concrete powder(cWCP)and provides an in-depth analysis of the carbonation process of WCP.It covers various carbonation methods,the regulation of carbonation degree and the prperties of carbonation products.Furthermore,the review evaluates the influence of cWCP on the performances of cement-based materials,including rheology,hydration behavior,mechanical properties,and impermeability. The carbonation products of cWCP are influenced by the carbonation conditions.In turn,cWCP influences the properties of cement-based materials through the properties of these carbonation products.The primary products of cWCP are CaCO3 and amorphous silica gel.Their composition,morphological characteristics,chemical properties,and relative distribution depend significantly on the carbonation method and conditions used.The reaction environments and carbonation kinetics of dry and wet carbonation processes differ significantly,resulting in variations in both the degree of carbonation and the polymorphs of products.By optimizing these carbonation conditions,it is possible to improve the degree of carbonation of cWCP while also controlling the polymorphs of CaCO3 and polymerization degree of silica gel.Furthermore,the influence exerted by these carbonation products on cement-based materials primarily stems from their surface characteristics combined with various effects.Surface properties include both geometrical and surface electrochemical characteristics of CaCO3 in diverse polymorphs,as well as the hydrophilicity of the silica gel.The effects of carbonation products include the filler effect,nucleation effect,chemical reaction with C3A,and the pozzolanic effect attributed to silica gel.Notably,improvements in rheological properties are not significantly influenced by either the filler effect or surface electrochemical characteristics of CaCO3.Instead,more pronounced negative influences arise from the hydrophilicity of silica gel and the fibrous geometry of aragonite.These factors contribute to a significant deterioration in rheological properties,with hydrophilicity being the primary mechanism behind this deterioration.When the degree of carbonation is sufficiently high,the combined positive effects of the filler effect,nucleation effect,chemical reaction,and pozzolanic effect can surpass the negative influence of dilution effect.As a result,the incorporation of cWCP accelerates the hydration,improves the microstructure,and enhances the compressive strength and impermeability. Summary and Prospects Existing studies have shown that the incorporation of cWCP accelerates cement hydration,improves microstructure,enhances compressive strength,and strengthens mortar impermeability.However,it may also result in a degradation in rheology. Base on these findings,further advancements are essential to fully understand the properties of cWCP-based cementitious materials and to support their widespread application.Key areas for development include:1)establishing a model that correlates carbonation conditions with carbonation products to precisely control their performance,2)addressing the contradiction between compressive strength and rheological properties,3)deepening our understanding of the durability of cement-based materials containing cWCP,particularly concerning corrosion of steel reinforcement,and 4)overcoming challenges related to improving the degree of carbonation in cWCP due to an accumulation of carbonation products.These efforts will lay the groundwork for the industrial adoption of cWCP and drive the concrete industry toward more sustainable and environmentally friendly practices.关键词
碳化废弃混凝土微粉/辅助性胶凝材料/碳酸钙/硅胶/性能/水化Key words
carbonated waste concrete powder/supplementary cementitious material/calcium carbonate/silica gel/property/hydration分类
建筑与水利引用本文复制引用
王明新,毛宇光,胡翔,郭帅成,史才军..碳化废弃混凝土微粉的特性及作辅助性胶凝材料的研究进展[J].硅酸盐学报,2025,53(5):1313-1327,15.基金项目
国家自然科学基金(U22A20122,52078204). （U22A20122,52078204）
