Effects of water-borne polyurethane on calcium silicate hydrate and toughness of properties of cementitious composites
A novel kind of block polymer with characteristics of rod-like chain conformations-water-borne polyurethane (PUA) was synthesized by incorporate polyacrylate (PA) into the PU chain to prepare an aqueous polyurethane-polyacrylate (PUA) hybrid emulsion with core-shell structure.The interactions between Water-borne PUA and C-S-H nanostructure,which include intercalation and the polymerization degree of C-S-H silicate chains,were studied by small angle X-ray diffraction spectra and 29Si NMR spectra,respectly.The influences of water-borne PUA on mechanical performance of C-S-H were investigated experimentally.The small XRD results show that no evidence is observed for any fundamental size change in the C-S-H particles that have been formed in the presence of polymer.The NMR results indicate that there is a significant increase in the Q2/Q1 ratio ranging from 0.5 for pure C-S-H to 2.2 for PUA-C-S-H,respectively.The degree of silicate polymerization increases from 3.0 for pure C-S-H to 6.4 for PUA-C-S-H by calculation.PUA had minimal harmful effect on the compressive strength whereas the flexural strength was increased by 23.2% with dosage of 0.5% and 23.3% with dosage of 1.0%,respectively.The fracture energy ratios of concrete with a dosage of PUA less than 1% are greatly improved more than double with the decreasing of concrete strength less than 10%.The water-borne PUA also enhances the impact resistance of concrete.The impact energy consumption of samples with PUA increase nearly three times more than reference samples,also better than samples with PP fiber.
Water-borne polyurethane calcium silicate hydrate concrete toughness fracture energy impact resistance
Ding Bei Zhang Xia Zhou Dongling Miao Chanwen
Jiangsu Research Institute of Building Science Co., Ltd., Nanjing Jiangsu, China Jiangsu Bote New materials Co., Ltd., Nanjing Jiangsu, China The National Key Laboratory of High Performance Building Materials, Nanjing, Jiangsu, China
国际会议
辽宁葫芦岛
英文
545-552
2012-08-07（万方平台首次上网日期，不代表论文的发表时间）