镍铁渣砂对泡沫混凝土孔结构及收缩开裂性能的影响

Effect of Ferronickel Slag Sand on Pore Structure and Shrinkage Cracking of Foamed Concrete

本文采用镍铁渣机制砂(简称镍铁渣砂)制备泡沫混凝土,研究镍铁渣砂对泡沫混凝土抗压强度、变形及收缩开裂的影响,并采用SEM、X-CT研究泡沫混凝土微观结构。结果表明,镍铁渣砂掺量为5%(质量分数,下同)时泡沫混凝土的抗压强度最高,而镍铁渣砂掺量超过10%时会引入界面缺陷,降低混凝土的强度。镍铁渣砂能够约束基体的变形,减少水泥用量,降低泡沫混凝土的收缩,提高其抗裂性能。当镍铁渣砂掺量由0%增加到20%时,泡沫混凝土的抗裂等级由V级提高到II级。镍铁渣砂具有作为泡沫混凝土生产原料的潜力。

In this study,ferronickel slag artificial sand(ferronickel slag sand)was used to produce foamed concrete.Effect of ferronickel slag sand on the compressive strength,deformation and shrinkage cracking of foamed concrete was investigated.Meanwhile,SEM and X-CT were used to investigate the microstructure.Experimental results reveal that the foamed concrete with 5%(mass fraction,the same below)ferronickel slag sand possesses the highest compressive strength.However,too many interfacial defects can be introduced with the addition of ferronickel slag sand above 10%,thus decreasing the compressive strength of the foamed concrete.The ferronickel slag sand can restrict the deformation of the matrix,decrease the usage of cement,mitigate the drying shrinkage of the foamed concrete,and enhance its crack resistance.When the content of ferronickel slag sand increased from 0%to 20%,the crack resistance grade of the foam concrete increases from V to II.Overall,ferronickel slag sand has potential to be used as a raw material in producing foamed concrete.