镁基泡沫混凝土配合比试验

Experiment of the Mixture Ratio of Magnesium-based Foam Concrete

分别以配制的氯氧镁水泥、硫氧镁水泥、磷酸镁水泥为胶凝材料,采用化学发泡制备干密度等级为A05的3种镁基泡沫混凝土。通过设计正交试验,确定水胶比、镁水泥组分配比、缓凝剂掺量、粉煤灰掺量和聚丙烯纤维掺量对3种镁基泡沫混凝土抗压强度的影响程度,对比分析影响因素的作用机理,建立镁基泡沫混凝土比强度与镁水泥组分配比的函数关系式。研究结果表明:氯氧镁泡沫混凝土抗压强度影响因素的主次关系为:镁水泥组分配比>水胶比>粉煤灰掺量>聚丙烯纤维掺量>缓凝剂掺量,各因素对硫氧镁泡沫混凝土抗压强度影响显著性与氯氧镁泡沫混凝土相同,磷酸镁泡沫混凝土抗压强度影响因素的主次关系为:镁水泥组分配比>缓凝剂掺量>水胶比>粉煤灰掺量>聚丙烯纤维掺量,与氯氧镁泡沫混凝土和硫氧镁泡沫混凝土略有不同,缓凝剂掺量影响程度较高;镁水泥的组分配比是影响镁基泡沫混凝土强度的重要指标,氯氧镁泡沫混凝土与硫氧镁泡沫混凝土的抗压强度随镁水泥组分配比增加的变化趋势相同,均先减小后增大,而磷酸镁泡沫混凝土随镁水泥组分配比增加呈现先增大后减小的趋势;3种镁基泡沫混凝土的比强度与镁水泥组分配比之间存在幂函数关系。

Three kinds of magnesium-based foamed concrete with dry density grade A05 were prepared by chemical foaming with magnesium oxychloride cement,magnesium oxysulfide cement and magnesium phosphate cement as cementing materials respectively.By designing orthogonal tests,the influences of water/cement ratio,magnesium cement component ratio,retarder content,fly ash content and polypropylene fiber content on the compressive strength of three kinds of magnesia-based foamed concrete were determined,the action mechanisms of the important influencing factors were compared and analyzed,and the functional relationships between the specific strength of magnesium-based foamed concrete and the component ratio parameters of magnesium-based foamed concrete were established.The results showed that the primary and secondary factors affecting the compressive strength of magnesium oxychloride foamed concrete were the ratio of magnesium cement components>water/cement ratio>fly ash content>polypropylene fiber content>retarder content.The influence of various factors on compressive strength of magnesium oxysulfide foam concrete was the same as that of magnesium oxychloride foam concrete.The relationship between the factors influencing the compressive strength of magnesium phosphate foamed concrete was as follows:the ratio of magnesium cement components>retarder content>water/cement ratio>fly ash content>polypropylene fiber content.Different from magnesium oxychloride foam concrete and magnesium oxysulfide foam concrete,the content of retarder had a higher degree of influence.The component ratio of magnesium cement was an important index affecting the strength of magnesia-based foamed concrete.The compressive strength of magnesium oxychloride foamed concrete and magnesium sulfide foamed concrete had the same change trend with the increase of the component ratio of magnesium cement,both of which first decreased and then increased,while magnesium phosphate foamed concrete showed the trend of first increased and then decreased with the increase of the component ratio of magnesium cement.There was a power function relationship between the specific strength of three kinds of magnesiumbased foamed concrete and the component ratio of magnesium-based foamed concrete.