Song Shanshan, Yu Hongfa, Ma Haiyan
Department of Civil and Airport Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
Materials (Basel). 2024 Feb 29;17(5):1131. doi: 10.3390/ma17051131.
The durability of concrete is critical for the service life of concrete structures, and it is influenced by various factors. This paper investigates the impact of the relative humidity (RH) of the curing environment on the durability of five different concrete types. The aim is to determine a suitable approach for designing concrete that is well-suited for use in the salt lake region of Inner Mongolia. The concrete types comprise ordinary Portland cement (OPC), high-strength expansive concrete (HSEC), high-strength expansive concrete incorporating silica fume, fly ash, and blast furnace slag (HSEC-SFB), steel fiber-reinforced high-strength expansive concrete (SFRHSEC), and high elastic modulus polyethylene fiber-reinforced high-strength expansive concrete (HFRHSEC). All these concrete types underwent a 180-day curing process at three distinct relative humidities (RH = 30%, 50%, and 95%) before being subjected to freeze-thaw cycles in the Inner Mongolia salt lake brine. The curing environment with a 95% RH is referred to as the standard condition. The experimental results reveal that the durability of OPC and HSEC decreases significantly with increasing relative humidity. In comparison with the control sample cured in 95% RH, the maximum freeze-thaw cycles for concrete cured in lower RHs are only 31% to 76% for OPC and 66% to 77% for HSEC. However, the sensitivity of the durability of HSEC-SFB, SFRHSEC, and HFRHSEC to variations in RH in the curing environment diminishes. In comparison with the corresponding reference value, the maximum freeze-thaw cycles for samples cured in dry conditions increase by 14% to 17% for HSEC-SFB and 21% for SFRHSEC. Specifically, the service life of HFRHSEC cured in a low RH is 25% to 46% higher than the reference value. The durability of HSEC-SFB, SFRHSEC, and HFRHSEC has been proven to be appropriate for structures located in the salt lake region of Inner Mongolia.
混凝土的耐久性对混凝土结构的使用寿命至关重要，且受多种因素影响。本文研究养护环境的相对湿度（RH）对五种不同类型混凝土耐久性的影响。目的是确定一种适合内蒙古盐湖地区使用的混凝土设计方法。混凝土类型包括普通硅酸盐水泥（OPC）、高强度膨胀混凝土（HSEC）、掺硅灰、粉煤灰和矿渣的高强度膨胀混凝土（HSEC - SFB）、钢纤维增强高强度膨胀混凝土（SFRHSEC）以及高弹性模量聚乙烯纤维增强高强度膨胀混凝土（HFRHSEC）。所有这些混凝土类型在三种不同的相对湿度（RH = 30%、50%和95%）下进行了180天的养护过程，然后在内蒙古盐湖卤水中进行冻融循环。RH为95%的养护环境被称为标准条件。实验结果表明，OPC和HSEC的耐久性随相对湿度增加而显著降低。与在95%RH下养护的对照样品相比，在较低RH下养护的混凝土，OPC的最大冻融循环次数仅为对照样品的31%至76%，HSEC为66%至77%。然而，HSEC - SFB、SFRHSEC和HFRHSEC的耐久性对养护环境中RH变化的敏感性降低。与相应参考值相比，在干燥条件下养护的HSEC - SFB样品的最大冻融循环次数增加了14%至17%，SFRHSEC增加了21%。具体而言，在低RH下养护的HFRHSEC的使用寿命比参考值高25%至46%。已证明HSEC - SFB、SFRHSEC和HFRHSEC的耐久性适用于内蒙古盐湖地区的结构。
