Huang Yuxiang, Ji Yongcheng, Wang Jingchen, Wang Zihao, Yu Bosong, Zhang Siyu
College of Aulin, Northeast Forestry University, Harbin 150040, China.
College of Civil Engineering and Transportation, Northeast Forestry University, Harbin 150040, China.
Materials (Basel). 2024 Sep 14;17(18):4529. doi: 10.3390/ma17184529.
The durability of concrete materials in harsh environmental conditions, particularly in cold regions, has garnered significant attention in civil engineering research in recent years. Concrete structures in these areas are often damaged by the combined effects of alkali-silica reaction (ASR) and freeze-thaw cycles, leading to structural cracks and significant safety hazards. Numerous studies have demonstrated that polypropylene fiber concrete exhibits excellent crack resistance and durability, making it promising for applications in cold regions. This study elucidates the impact of alkali content on concrete durability by comparing the mechanical properties and durability of different alkali-aggregate concretes. The principal experimental methodologies employed include freeze-thaw cycle experiments, which examine patterns of mass loss; fluctuations in the dynamic modulus of elasticity; and changes in mechanical properties before and after freeze cycles. The findings indicate that increased alkali content in concrete reduces its strength and durability. At 100% alkali-aggregate content, compressive strength decreases by 35.5%, flexural strength by 32.9%, mass loss increases by 35.85%, relative dynamic elastic modulus by 39.4%, and residual strength by 97.28%, indicating higher alkali content leads to diminished durability. Additionally, this paper introduces a constitutive damage model, validated by a strong correlation with experimental stress-strain curves, to effectively depict the stress-strain relationship of concrete under varying alkali contents. This research contributes to a broader understanding of concrete durability in cold climates and guides the selection of materials for sustainable construction in such environments.
近年来，混凝土材料在恶劣环境条件下，尤其是寒冷地区的耐久性，在土木工程研究中受到了广泛关注。这些地区的混凝土结构常常因碱 - 硅反应（ASR）和冻融循环的综合作用而受损，导致结构出现裂缝并带来重大安全隐患。大量研究表明，聚丙烯纤维混凝土具有出色的抗裂性和耐久性，在寒冷地区的应用前景广阔。本研究通过比较不同碱 - 骨料混凝土的力学性能和耐久性，阐明了碱含量对混凝土耐久性的影响。所采用的主要实验方法包括冻融循环实验，该实验考察质量损失模式、动态弹性模量的波动以及冻融循环前后力学性能的变化。研究结果表明，混凝土中碱含量的增加会降低其强度和耐久性。在碱 - 骨料含量为100%时，抗压强度降低35.5%，抗折强度降低32.9%，质量损失增加35.85%，相对动弹性模量降低39.4%，残余强度降低97.28%，这表明较高的碱含量会导致耐久性下降。此外，本文还引入了一个本构损伤模型，该模型通过与实验应力 - 应变曲线的强相关性得到验证，以有效描述不同碱含量下混凝土的应力 - 应变关系。本研究有助于更广泛地理解寒冷气候下混凝土的耐久性，并为这种环境下可持续建筑的材料选择提供指导。
