早强型水下不分散水泥基复合材料的性能优化设计

Performance optimization design of early strength underwater nondispersed cement-based composite materials

针对严酷服役环境条件中水下混凝土抗拉变形能力差、开裂引发的一系列病害,在水泥浆体中掺入抗分散剂UWB-Ⅲ、粉煤灰、减水剂、速凝剂、聚乙烯醇纤维、煤矸石等物质,研究各物质不同掺量对水泥基材料的抗分散性能、水陆强度、微观形貌的影响。结果表明,适量的UWB-Ⅲ可以显著改善浆体的抗分散性能,但过量使用UWB-Ⅲ会降低砂浆的流动性。当UWB-Ⅲ掺量为6.5%时,能够较好的兼顾抗分散性能和流动性。随着粉煤灰或煤矸石替代率的增加,材料抗压强度降低,悬浊物含量增大。随着减水剂、速凝剂、聚乙烯醇纤维等掺量的增加,材料抗压强度呈现先增大后减小的趋势。综合分析可知UWB-Ⅲ掺量6.5%,粉煤灰替代率20%,水胶比0.24,减水剂0.5%,速凝剂2%,纤维掺量2%,煤矸石替代率60%的水泥基复合材料具备早强、水下不分散等特点。研究可为水下混凝土开裂提供一种快速修补方法,也可对煤研石进行资源化利用。

In response to a series of diseases caused by poor tensile deformation ability and cracking of underwater concrete under harsh service environment conditions,substances such as anti dispersant UWB-Ⅲ,fly ash,water reducing agent,accelerating agent,polyvinyl alcohol fiber,coal gangue,etc.were added to the cement slurry to study the effects of different dosages of each substance on the anti dispersion performance,water land strength,and micro morphology of cement-based materials.The results indicate that an appropriate amount of UWB-Ⅲ can significantly improve the anti dispersion performance of the mortar,but excessive use of UWB-Ⅲ will reduce the fluidity of the mortar.When the content of UWB-Ⅲ is 6.5%,it can effectively balance the anti dispersion performance and flowability.As the replacement rate of fly ash or coal gangue increases,the compressive strength of the material decreases and the content of suspended matter increases.With the increase of water reducer,accelerator,polyvinyl alcohol fiber and other additives,the compressive strength of the material shows a trend of first increasing and then decreasing.Comprehensive analysis shows that the cement-based composite material with a UWB-Ⅲ content of 6.5%,a fly ash replacement rate of 20%,a water cement ratio of 0.24,a water reducing agent of 0.5%,a rapid setting agent of 2%,a fiber content of 2%,and a coal gangue replacement rate of 60%,has the characteristics of early strength and underwater non dispersion.This study can provide a rapid repair method for underwater concrete cracking,and can also be used as a resource for coal grinding stone.