泡沫轻质混凝土渗透性试验研究

Experimental research on permeability of foamed lightweight concrete

渗透性是影响混凝土材料耐久性的重要因素。以普通硅酸盐水泥为胶凝材料,采用物理发泡技术预制泡沫制备泡沫轻质混凝土,通过改进的渗透试验方法,研究了密度与泡沫轻质混凝土渗透性能的相关性,并探讨了水灰比和玻璃纤维、粉煤灰、硅粉等外加剂对泡沫轻质混凝土抗渗性的影响。结果表明:泡沫轻质混凝土的渗透时间随着密度的增大而延长;随着水灰比的增大,呈现出先延长后缩短的现象;3种外加剂对低密度泡沫轻质混凝土抗渗性能的改善效果并不明显,但在合适掺量范围内,可显著提高较大密度(700和1000 kg/m3)泡沫轻质混凝土的抗渗性能。

Permeability is one of the most important factors which affect concrete durability. In this paper, foamed lightweight concrete was prepared by using physical preformed foam binding with ordinary Portland cement slurry, and the correlation between density and permeability was investigated based on a modified permeability test method. In addition,the effects of water cement ratio,glass fiber, fly ash,silica fume on the permeability were discussed. Test results showed that penetration time of foamed lightweight concrete increased as the increase of density,but increased at first and then decreased with the increase of water cement ratio. Three additives had little influence on the improvement of impermeability for the samples with low density,while within the appropriate dosage range,adding additive could significantly improve the impermeability of foamed /ightweight concrete （with bigger density of 700 and 1000 kg/m3）.