Thermal and mechanical properties of structural lightweight concrete containing lightweight aggregates and fly-ash cenospheres
Thermal and mechanical properties of structural lightweight concrete containing lightweight aggregates and fly-ash cenospheres
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DOI：
10.1016/j.conbuildmat.2018.11.074
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发表时间：
2019-02
影响因子：
7.4
通讯作者：
Hongyu Zhou;A. Brooks
中科院分区：
文献类型：
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作者：
Hongyu Zhou;A. Brooks
研究了配合比、骨料类型和微观结构对含轻骨料和粉煤灰空心微珠（FAC）等轻质功能填料的结构轻质混凝土（LWC）热学和力学性能的影响。特别地，FAC被掺入混合物中以降低材料的密度和热导率，同时保持高机械强度。试验结果表明，轻骨料混凝土的弹性模量和导热系数随混凝土密度的降低而线性降低，而抗压强度主要取决于材料的微观结构。使用扫描电子显微镜（SEM）和轻质填料与混凝土中其他相之间的相互作用（即，水泥粘结剂和骨料-进行了研究。对LWC试样进行力学性能测试的SEM图像表明，坚固的FAC壳层可以提供阻碍微裂纹形成和扩展的屏障。最后，提出了一个两步均匀化方案来估计轻质混凝土的热性能FAC和骨料。计算结果与实验数据吻合较好。
This study investigates the effects of mix proportion, aggregate type, and microstructures on the thermal and mechanical behaviors of structural lightweight concrete (LWC) containing lightweight aggregates and lightweight functional fillers such as fly-ash cenospheres (FAC). Particularly, FAC are incorporated into the mixtures to reduce the materials’ density and thermal conductivity while maintaining high mechanical strength. The experimental results indicate that the elastic modulus and thermal conductivity of LWC decrease linearly with respect to the reduction in concrete density, while compressive strength depend largely on material microstructures. The hierarchically porous microstructure of FAC-containing LWC were investigated using scanning electron microscopy (SEM) and the interactions between lightweight fillers and other phases in concrete – i.e., the cementitious binder and aggregates – are investigated. SEM images taken on mechanically tested LWC samples indicated that the strong FAC shell may provided barriers to hinder micro-crack formation and propagation. Lastly, a two-step homogenization scheme was proposed to estimate the thermal properties of lightweight concrete containing both FAC and aggregates. The results calculated using this method shows good agreement with experimental data.