Study on Concrete Performance of CRTS Ⅲ Track Slab with Nano Calcium Silicate Hydrate External Admixture Under Steam-Free Curing
Adding 1.0％mass fraction of nano calcium silicate hydrate to CRTS Ⅲ track slab concrete,the mechanical properties,durability,and microstructure of CRTS Ⅲ track slab concrete cured by steam curing and insulation curing were compared by temperature tester and universal testing machine.The feasibility of CRTS Ⅲ track slab concrete steam-free curing was explored.The results show that under insulation curing with an initial temperature of 25 ℃ and 16 h of curing,the compressive strength of concrete can reach the demolding strength requirement of 45 MPa.Compared with steam cured concrete,the electrical flux and chloride ion diffusion coefficient of insulation cured concrete decreased by 15.6％and 15.8％respectively after 56 d.Moreover,hydration products are denser,and micro-cracks are significantly reduced.After enduring 300 freeze-thaw cycles,the relative dynamic elastic modulus of insulation cured concrete at 28 d and 56 d increases by 7.8％and 3.1％respectively compared to steam cured concrete.Overall,the performance of concrete cured with steam-free method surpasses that of steam cured concrete in various aspects,suggesting its potential application in engineering projects.
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