Polyvinyl-Alcohol-Modified Calcium Sulphoaluminate Cement Repair Mortar: Hydration and Properties |
| |
| Authors: | Yongjie Bian Yongbo Huang Fuxin Li Dong Dong Honggen Zhao Piqi Zhao Lingchao Lu |
| |
| Institution: | 1.Shandong Provincial Key Lab of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022, China; (Y.B.); (D.D.); (H.Z.); (P.Z.); (L.L.);2.State Key Laboratory of Green Building Materials, China Building Materials Academy, Beijing 100024, China;3.China United Cement Pingyi Co., LTD, Pingyi 273300, China; |
| |
| Abstract: | Polyvinyl alcohol (PVA) and calcium sulphoaluminate (CSA) cement were used to prepare repair mortar for the restoration of the walls of a building built with bricks. The preparation, hydration, and properties of the PVA-modified CSA cement repair mortar were studied. Besides this, the mechanism by which PVA improves the bonding strength is also discussed. The results demonstrate that PVA prolongs the setting time of CSA cement, which is ascribed to PVA inhibiting the dissolution of C4A3$ (4CaO·3Al2O3·SO3) and the precipitation of AFt (3CaO·Al2O3·3CaSO4·26H2O) within the hydration age of 0~60 min. PVA lowers the mechanical strength of CSA cement repair mortar at the hydration age of 6 h. After 6 h, the mechanical strength is improved. PVA could also improve the bonding strength between CSA repair mortar and bricks. This is mainly ascribed to the Al ions in both the hydration products of CSA cement and the clay bricks reacting with the hydroxyl group of PVA and forming the chemical bond C-O-Al. Therefore, a tighter combination between CSA cement repair mortar and the clay bricks forms, thereby improving the bonding strength. |
| |
| Keywords: | polyvinyl alcohol calcium sulphoaluminate cement repair mortar hydration and properties |
|
|
