CaO-粉煤灰地质聚合物早期强度影响因素研究

Research on Influencing Factors of Early Strength of CaO-Fly Ash Geopolymer

为研究加钙粉煤灰地质聚合物早期强度的影响因素,以CaO为外加钙源,设计正交实验和单一变量实验,研究CaO掺入量、水玻璃掺入量、水玻璃模数、固化条件对其早期强度的影响,并通过MIP分析80℃固化温度下不同固化时间地质聚合物孔隙率的变化.结果表明,加钙粉煤灰地质聚合物早期强度的敏感因素由大到小依次为养护温度、CaO掺入量、水玻璃掺入量、水玻璃模数;适当提高养护温度和延长养护时间可显著提高地质聚合物的强度,最佳覆膜养护固化温度为80℃,持续固化3 d的抗压强度和抗折强度最大;加钙粉煤灰地质聚合物的孔隙率随固化时间的增加先减小后增大,当凝胶孔隙的占比最大、孔隙率最低时其强度最大.

In order to study the factors influencing the early strength of calcium-enhanced fly ash geopolymers,CaO was selected as the external calcium source,and orthogonal experiments and univariate experiments were designed to investigate the effects of CaO admixture,water glass admixture,water glass modulus and curing conditions on their early strength,and the changes in porosity of the geopolymer at different curing times at 80℃curing temperature by MIP analysis as well.The results show that the sensitive factors for the early strength of the geopolymer are,in order of importance,the maintenance temperature,the CaO admixture,the water-glass admixture and the water-glass modulus.Appropriate increasing maintenance temperature and extended maintenance time can significantly improve the strength of the geopolymer,the best curing temperature for film curing is 80℃,and the maximum compressive strength and flexural strength can be reached by continuous curing for 3 days.The porosity of the geopolymer first decreases and then increases with the curing time,and the gel pores account for the largest proportion.The strength with the lowest porosity is the highest.