In this study, a model for evaluating the CO₂ uptake rate of plain concrete and limestone-powder-blended concrete in both the service and recycling phases was proposed. First, a blended cement hydration model was proposed to evaluate the content of carbonatable substances, porosity and carbon dioxide diffusivity. In the service phase, a one-dimensional carbonation model was proposed to evaluate the carbonation depth. In the recycling stage, an unreacted core model was proposed to evaluate the carbonation process of spherical recycled concrete. Secondly, considering the concrete materials, structural elements and environmental exposure, a CO₂ uptake model at the service stage and recycling stage was proposed. The total CO₂ uptake rate is the sum of the CO₂ uptake rates in the service stage and the recycling stage. The analysis results showed (1) as the limestone replacement rate increased from 0% to 20% (water–binder ratio is 0.3), the CO₂ uptake rate in the service phase increased from 3.12% to 3.84%, and the total CO₂ uptake rate increased from 22.82% to 26.11%. (2) Given a certain concrete mixture, as the surface area to volume ratio of structural units increased, or the amount of recycled concrete decreased, the CO₂ uptake rate increased, but the total CO₂ uptake rate did not change. (3) Given a certain limestone powder replacement ratio, as the water/binder ratio increased, the total CO₂ uptake ratio increased. The contributions of this study are 1) propose an integrated hydration-carbonation-CO₂ uptake model for limestone blended concrete, 2) clarify the differences of carbonation equations between service stage and recycling stage, and 3) determine the effects of concrete mixtures, structural element sizes and types, life cycle stages, and recycled concrete sizes on CO₂ uptake.

在这项研究中，提出了用于评估在服务阶段和回收阶段的普通混凝土和石灰石粉混合混凝土对CO ₂吸收率的模型。首先，提出了一种混合水泥水化模型，以评估可碳化物质的含量，孔隙率和二氧化碳扩散率。在服务阶段，提出了一个一维碳化模型来评估碳化深度。在回收阶段，提出了一种未反应的岩心模型来评估球形再生混凝土的碳化过程。其次，考虑混凝土材料，结构元素和环境暴露，提出了服务阶段和回收阶段的CO ₂吸收模型。总的CO ₂吸收率是CO的总和服务阶段和回收阶段的₂吸收率。分析结果表明（1）随着石灰石替代率从0％增加到20％（水与水的比例为0.3），服务阶段的CO ₂吸收率从3.12％增加到3.84％，总CO ₂吸收率从22.82％增加到26.11％。（2）在一定的混凝土混合比下，随着结构单元的表面积与体积之比的增加，或再生混凝土的用量的减少，CO ₂吸收率增加，但总CO ₂吸收率没有变化。（3）给定一定的石灰石粉替代率，随着水灰比的增加，总CO ₂吸收率增加。这项研究的贡献是：1）为石灰石混合混凝土提出了一个综合的水合作用-碳酸化-CO ₂吸收模型，2）阐明了服务阶段和回收阶段之间碳酸化方程的差异，以及3）确定了混凝土混合物，结构的影响。元素的大小和类型，生命周期阶段以及回收的CO ₂吸收的混凝土尺寸。