Study on the Activity of Silty Sandstone Powder for Road Bed Excavation
The recycling of roadbed excavation stone is an effective way to reduce carbon emissions.The fine grinding powder of sandstone waste rock excavated from the roadbed is used as a mineral admixture to partially replace cement.The strength test of sandstone powder cement adhesive is carried out,and the internal pore structure,hydration products,and morphology of the sandstone powder cement composite adhesive system are tested.The results showed that with the increase of sandstone powder content,the compressive strength of cement mortar gradually decreased,the proportion of total porosity and harmful pores(pore size above 100nm)gradually increased,and the proportion of less harmful pores(pore size in 20～100nm)and harmless pores(pore size below 20nm)decreased.But with the extension of age,the pore size gradually becomes finer,and after hydration to 180 days,the distribution of critical pore size is mainly concentrated at 5～50nm.The ash activity of fly ash powder is low,and the amount of Ca(OH)2 consumed through secondary hydration reaction is very limited.It is recommended to control the content of sandstone powder in concrete within 20%to achieve good comprehensive performance.
万方数据
维普
