改性玄武岩纤维混凝土的力学与变形性能及微观机理研究

Study on Mechanics,Deformation Property and Microscopic Mechanism of the Modified Basalt FiberConcrete

为了改善玄武岩纤维混凝土材料的强度和收缩性能,本文采用了玄武岩纤维、芒硝、粉煤灰、脱硫石膏作为外掺料进行混凝土的配制,并按照正交实验的方法确定不同材料的最佳配合比例,最后开展XRD半定量分析与SEM扫描电镜实验对改性混凝土的微观结构进行了探测。结果表明:改性外掺料的等质量替代水泥的最佳配合比为:粉煤灰掺量10%、脱硫石膏掺量8%、芒硝掺量0.5%以及玄武岩纤维掺1.5%;经过复合材料改性后混凝土的抗折强度和抗压强度分别提高了0.48和2.1倍;干缩率减小了0.56倍;从SEM图像中观察到材料中有大量水化凝胶产物包裹玄武岩纤维,粉煤灰和石膏颗粒填充在孔隙中,矿物水化程度和微观结构的变化是改性玄武岩纤维混凝土材料收缩性和强度增强的根本原因。

In order to improve the strength and shrinkage properties of basalt fiber concrete,basalt fiber,mirabilite,gypsum,fly ash and basic materials were used as experimental materials to make up the concrete.The optimum proportion of three admixtures in cement mortar was studied by orthogonal tests.The microcosmic mechanism of modified materials was studied by XRD and SEM.The results showed that the optimal proportions of modified high-water backfill materials were consisted of basalt fiber content of 1.5%,sal glauberi content of 0.5%,desulfurization gypsum content of 10%,fly ash content of 10%.The flexural strength and compressive strength of the material were increased by 3.58 times and 1.62 times respectively and the shrinkage rate was reduced by 0.82 times after modification.There were many gel products wrapped basalt fiber and cement and gypsum particles filled in the pores.The degree of mineral hydration and microstructure changes were the fundamental reasons for the improvement of shrinkage and strength of modified basalt fiber concrete.