纳米二氧化硅掺量对混凝土冻结温度的影响OA

Currently,research on the freeze-thaw durability of nano-silica(NS)enhanced concrete primarily focuses on the influence of different NS content,while quantitative studies on the freezing temperature of NS-modified concrete are still lacking.Although existing theories and mechanistic studies suggest that NS may lower the freezing temperature of concrete,experimental data and quantitative analyses are still relatively scarce.In this work,physical experiments were conducted to measure the temperature variation curves of C40 concrete with different NS content,and the freezing temperature was quantitatively characterized.Microscopic analysis of the pore structure was performed using the nuclear magnetic resonance(NMR)technology.The results show that within the experimental content range(0%,1%,2%,and 3%,mass fraction),the freezing temperature of concrete decreases significantly with increasing NS content.When the NS content is 2%,the optimization effect on the pore structure is most remarkable,and the relative reduction in freezing temperature is most pronounced,particularly as the NS content increases from 1%to 2%.The results of this study supplement the research on the effect of NS on the freezing temperature of concrete,provide a reference for further investigation into the freeze-thaw damage mechanism of NS-modified concrete,and offer a basis for optimizing NS content in concrete engineering in different cold regions.