Synthesis and Multi-Scale Characterization of Calcium Silicate Hydrate at Multiple CaO/SiO2 Mixture Ratios

摘要: Calcium Silicate Hydrate (C-S-H) is the primary binding agent that responsible for setting and hardening, strength, dimensional stability, durability of Portland cement paste. Although hydration produces C-S-H, hydroxide (CH), ettringite, other products are also acquired from this process make it difficult to characterize C-S-H exclusively. was first synthesized by mixing calcium oxide (CaO), created calcining carbonate (CaCO3) heated 950 oC 24 hours with fumed silica (SiO2) deionized water (H2O) under nitrogen which produced synthetic gel-like slurry. This composition mixture mixed continuously 7 days a constant speed transferred filtration system removal excess water. The gel then drying unit purged in 5 weeks relative humidity (RH) 11% using Lithium Chloride (LiCl) weeks. Specimens were obtained compacting dried powder at 500 MPa. These compacted samples tested identifying its mechanical properties on macro, micro, nano-scale levels. Nanoindentation vi used identify creep compliance reduced elastic modulus C-S-H. tests confirmed 0.7 C/S ratio stiffer (higher modulus) than 1.5 ratio. Furthermore, has lower compared ratios. Microstructural investigations 29 Si nuclear magnetic resonance (NMR) Transmission Electron Microscopes (TEM) performed specimens. work shed light significance silicate polymerization behavior concrete. might lead developing alternative cements concrete structures timedependent critical applications.