Chen Liangliang, Wu Fufei, Liu Daqing, Huang Chuanteng, Pu Shuang, Wang Jing, Luo Pengfei
School of Civil Engineering, Huzhou Vocational and Technical College, Huzhou 313000, China.
Huzhou Key Laboratory of Green Building Technology, Huzhou Vocational and Technical College, Huzhou 313000, China.
Materials (Basel). 2025 May 10;18(10):2201. doi: 10.3390/ma18102201.
To investigate the sulfate resistance of recycled concrete with composite admixtures under dry-wet cycling, a single-factor experimental design was first conducted to study the deterioration patterns of recycled concrete with single and composite admixtures (ground granulated blast furnace slag (GGBS) and fly ash) under sulfate attack. Based on the single-factor test results, orthogonal experiments were designed with composite admixtures as one influencing factor. Quantitative analysis was performed to determine the impact magnitude and significance of various factors on the sulfate resistance of recycled concrete at different corrosion ages. A damage model for recycled concrete under sulfate dry-wet cycling was established for preliminary service life prediction. The experimental results indicated that the sulfate resistance performance followed the sequence of composite admixtures > single slag admixture > single fly ash admixture. When uncycled (0 cycles), the influence ranking of factors was B (water-binder ratio) > A (recycled coarse aggregate replacement rate) > C (GGBS + fly ash content). After 60 and 120 cycles, the ranking became B > C > A. For the compressive strength regression model, the measured values deviated significantly from the calculated values (-6.88% to 16.66%), while the dynamic elastic modulus model showed good agreement between the measured and calculated values (-2.86% to 4.87%). A three-indicator lifespan prediction equation was established. Using practical engineering parameters (30% recycled aggregate replacement, 0.4 water-binder ratio, 20% fly ash and 20% slag content), the predicted service life of this recycled concrete project was = 117 years. Therefore, incorporating fly ash and slag can effectively improve weak zones in recycled concrete and enhance its durability.
为研究干湿循环作用下复掺掺和料再生混凝土的抗硫酸盐性能，首先采用单因素试验设计，研究单掺和复掺掺和料（磨细粒化高炉矿渣（GGBS）和粉煤灰）再生混凝土在硫酸盐侵蚀下的劣化规律。基于单因素试验结果，以复掺掺和料为一个影响因素设计正交试验。进行定量分析，以确定不同腐蚀龄期各因素对再生混凝土抗硫酸盐性能的影响程度和显著性。建立了硫酸盐干湿循环作用下再生混凝土的损伤模型，用于初步的使用寿命预测。试验结果表明，抗硫酸盐性能顺序为复掺掺和料＞单掺矿渣掺和料＞单掺粉煤灰掺和料。未循环（0次循环）时，因素影响排序为B（水胶比）＞A（再生粗骨料取代率）＞C（GGBS+粉煤灰含量）。60次和120次循环后，排序变为B＞C＞A。对于抗压强度回归模型，实测值与计算值偏差较大（-6.88%至16.66%），而动弹模量模型的实测值与计算值吻合较好（-2.86%至4.87%）。建立了三指标寿命预测方程。采用实际工程参数（再生骨料取代率30%、水胶比0.4、粉煤灰含量20%、矿渣含量20%），该再生混凝土工程的预测使用寿命为 = 117年。因此，掺入粉煤灰和矿渣可有效改善再生混凝土的薄弱环节，提高其耐久性。
