The Structure And Bonding Linkage Mechanism Of The Calcium Silicate Hydrates Contained The Organic Complex Molecule

Cement-based materials contained the organic complex molecule are playing important roles in national economy. However, the basic research on bonding linkage and structure between organic complex molecules and the main hydrate product of the Portland cement -the calcium silicate hydrates needs more work. In view of the research situation, the effect of different organic complex molecules on morphology, crystallinity and structure of the calcium silicate hydrates has been studied in the thesis. The bonding linkage mechanism between organic complex molecule and the calcium silicate hydrates is discussed, too.Calcium silicate hydrates (abbr. C-S-H) and C-S-H contained organic complex molecule are synthesized by the chemical agent Na2SiO3 · 9H2O, Ca(NO3)2 ·4H2O and three superplasticizers, respectively. The effect of three superplasticizers on the composition and structure of C-S-H is characterized by XRD, SEM, XPS, FTIR and TEM. The results show that the shape of the C-S-H contained the organic complex molecule is different from that of the pure C-S-H. The higher the content of the organic complex molecule contained in the C-S-H is, the closer would be the conglomeration of the C-S-H. Three superplasticizers could increase the crystallinity of the C-S-H. The effect of the naphthalene-type superplasticizer is the most distinct among three superplasticizers and there are three crystal spots in the TEM lattice image of the sample. The organic complex molecule of three superplasticizers intercalates into the inner interlayer surface of the C-S-H.The bonding linkage mechanism between the organic complex molecule and the C-S-H has been discussed. The results show that the Ca2+ is ionically bonded to the -O-Si-O- linkage of the inorganic bridge and to the functional group of the organic complex molecule so that theionically crosslinked structure is formed. Through the formation of the crosslinked structure, the organic complex molecule intercalates into the inner interlayer the C-S-H.According to the hydration kinetics of the sheet formation of C-S-H, the transformation from gels to crystal of the C-S-H is analyzed. It could be drawn that the transformation process depends on the ratio of the Kg/Kn and the water-dispersible organic complex molecule. It could be speculated that the organic complex molecule could make an active effect on the nucleation process of the C-S-H because of the similar structure between the buckled sheet of C-S-H and the organic complex molecule. The organic complex molecule could provide more nanocrystalline region and promote the transformation from gels to crystal of the C-S-H.