文章摘要
王骞,郑忠良,尤博,张兆彪,李宇翔,曹明莉.基于综合性能试验的混凝土早期开裂行为研究[J].,2024,64(1):82-89
基于综合性能试验的混凝土早期开裂行为研究
Study of early cracking behavior of concrete based on comprehensive performance experiment
  
DOI：10.7511/dllgxb202401010
中文关键词: 水化热  开裂行为  抗裂性能  早期收缩  矿物掺合料
英文关键词: hydration heat  cracking behavior  crack resistance performance  early shrinkage  mineral admixtures
基金项目:国家自然科学基金资助项目(51478082).
作者单位
王骞,郑忠良,尤博,张兆彪,李宇翔,曹明莉  
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中文摘要:
      为提高混凝土的早期抗裂性能，突破单因素改善其早期稳定性，进行了多因素补偿混凝土各性能缺陷方面的研究．基于调控混凝土配合比开展了胶凝材料水化热、混凝土早期收缩试验和大板加速开裂试验．通过相关收缩机理分析了不同混凝土拌和物的开裂行为；运用双参数Weibull分布分析试验结果，得出了混凝土大板裂缝经时开裂规律．试验结果表明：采用高效稳定型聚羧酸减水剂可以增加浆体的和易性，结合66.7%矿物掺合料(粉煤灰和矿渣粉与水泥质量比)、较好级配碎石和0.29的水胶比有利于延长混凝土的初裂时间和控制裂缝宽度，即提高混凝土的早期抗裂性能．同时，该调控手段也可以降低浆体的水化热，提高混凝土的抗压强度．此外，混凝土裂缝宽度的经时变化规律很好地服从双参数Weibull分布．
英文摘要:
      To improve the early crack resistance performance of concrete and break through the single factor to enhance its early stability, research on multiple factor compensation for various performance defects of concrete is carried out. The experiments on hydration heat of cementitious materials, early shrinkage of concrete and accelerated cracking of concrete slab are conducted by adjusting the concrete mix proportions. The cracking behavior of different concrete mixtures is analyzed through an investigation of relevant shrinkage mechanisms. The experimental results are further examined using a dual-parameter Weibull distribution to derive the time-dependent variation rule of crack of concrete slab. The experimental results indicate that the use of high-efficiency and stabilized polycarboxylic acid water-reducing agent can enhance the workability of the paste. Furthermore, incorporating 66.7% of mineral admixtures (the mass ratio of fly ash and slag powder to cement), well-graded gravel and 0.29 of water-cement ratio are beneficial for prolonging the initial cracking time of concrete and controlling crack widths. This method can effectively improve the early crack resistance performance of concrete. Additionally, this control method can reduce the hydration heat of the paste and improve the compressive strength of the concrete. Furthermore, the time-dependent variation rule of concrete crack width exhibits a good fit to the dual-parameter Weibull distribution.
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