Enhancement in compressive strength of foamed concrete by ultra-fine slag
Enhancement in compressive strength of foamed concrete by ultra-fine slag
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DOI：
10.1016/j.cemconcomp.2023.104954
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发表时间：
2023-02-17
影响因子：
10.5
通讯作者：
Lin, Xiaoli
中科院分区：
文献类型：
--
作者：
Li, Maogao;Tan, Hongbo;Lin, Xiaoli
为了提高泡沫混凝土的抗压强度，采用超细矿渣代替波特兰水泥制备泡沫混凝土。设计了PC-UFS体系，UFS对水泥的替代率分别为10%、20%、30%和40%。测定了7 d、14 d和28 d的抗压强度，并对流动性进行了评价。采用纳米压痕法对PC-UFS泡沫混凝土的硬度进行了表征。采用XRD、TGA、SEM和29 Si-NMR等手段研究了相关机理，并采用X射线显微CT分析了孔结构。结果表明，PC-UFS泡沫混凝土的抗压强度高于PC泡沫混凝土，S 0（0% UFS）的7 d和28 d抗压强度分别为4.46 MPa和6.99 MPa，S40（40% UFS）的7 d和28 d抗压强度分别为5.59 MPa和7.75 MPa，提高了25%和11%。其原因是UFS具有很好的填充和颗粒分级作用，同时还发现UFS加速了C-A-S-H凝胶的形成，使微结构致密化。此外，添加UFS减小了孔隙的平均直径和直径分布。这些结果为改善泡沫混凝土的力学性能提出了一种新的方法。
In this study, ultra-fine slag (UFS) was used to prepare foamed concrete by replacing Portland cement (PC) to enhance the compressive strength of foamed concrete. PC-UFS system was designed and the replacement ratio of UFS to cement was 10%, 20%, 30% and 40%. The compressive strength at the age of 7 d, 14 d and 28 d were measured, and the fluidity was evaluated. The hardness of PC-UFS foamed concrete was characterized by nanoindentation test. The related mechanism was researched by XRD, TGA, SEM and 29Si-NMR, and pores structure was analyzed by X-ray micro-computed tomography. Results exhibited that the compressive strength of PC-UFS foamed concrete was higher than that of PC foamed concrete, noting that the 7 d and 28 d compressive strength of S0 (0% UFS) was 4.46 MPa and 6.99 MPa, and that of S40 (40% UFS) reached to 5.59 MPa and 7.75 MPa, with an increase by 25% and 11%. The reason was that UFS showed a great filling and particle grading effect, and it was also found that UFS accelerated the formation of C-A-S-H gel and densified the microstructure. Moreover, adding UFS decreased the average diameter and the diameter distribution of the pores. Such results proposed a novel method to improve the mechanical properties of foamed concrete.