硅灰掺量对自密实高强混凝土性能影响研究

Research on the effect of silica ash content on the performance of self compacting high-strength concrete

文章配制自密实高强混凝土,胶凝材料总量为530 kg,粉煤灰、矿渣、水泥质量比为15∶25∶60。然后分别用3.0%、4.5%、6.0%、7.5%、9.0%的硅灰等质量替换水泥,研究硅灰掺量对自密实高强混凝土工作性能和力学性能的影响。文章研究表明,适量的硅灰掺加能改善自密实混凝土的工作性能,减小扩展时间,增大扩展度。当硅灰掺量为6.0%时,扩展时间最短;掺加硅灰能明显提高自密实混凝土拌合物的保坍性能,当硅灰掺量为6.0%时,1 h保坍性能最优;掺加硅灰后,混凝土成型均匀,密实度更高,试块装模和脱模都更方便;适当地在自密实混凝土中掺加硅灰,能提高混凝土抗压强度。

Prepare self compacting high-strength concrete with a total amount of 530 kg of cementitious materials,and a mass ratio of 15∶25∶60 for fly ash,slag,and cement.Then replace cement with 3%,4.5%,6%,7.5%,and 9%silica fume,and study the effect of silica fume content on the workability and mechanical properties of self compacting high-strength concrete.The research in the article shows that an appropriate amount of silica fume addition can improve the workability of self compacting concrete,reduce expansion time,and increase expansion degree.When the content of silica fume is 6%,the expansion time is the shortest.The addition of silica fume can significantly improve the slump retention performance of self compacting concrete mixtures.When the silica fume content is 6%,the 1-hour slump retention performance is optimal.After adding silica fume,the concrete is formed more uniformly and compactly,and the installation and demolding of test blocks are more convenient.Adding silica fume appropriately to self compacting concrete can improve its compressive strength.