| Polymer impregnation treatment can significantly improve the performance of cement-based materials,so it has potential application value in the field of marine structure anticorrosion,in-service concrete structure repair,prefabricated component impregnation and so on.Polymer impregnation treatment plays an important role in realizing the life cycle management of concrete structures.The promotion of polymer impregnation technology requires experimental research into the impregnation process and the performance of the treated cement-based materials.In this paper,tests of mechanical properties,durability performance and microstructure were carried out on polyacrylate impregnated mortars using methyl methacrylate（MMA）and butyl methacrylate（BMA）as impregnating materials.The laws of impregnation and polymerization conditions on the performance of polyacrylate impregnated mortars were investigated.The effect of polymer impregnation treatment on mortar performance was analyzed.The main work and research results are as follows.（1）Based on the polymer loading measurement test,the effects of coating amount and monomer type on the polymer loading of polyacrylate impregnated mortar were investigated.The test results indicate that the polymer loading of mortar was proportional to the coating amount and had extreme value.The increase of the percentage of BMA in monomer affects the maximum polymer loading of mortar.（2）The mechanical strength tests of mortar were carried out to obtain the mechanical strength of polyacrylate impregnated mortar with different initiator dosage,coating amounts,polymerization time and monomer type.The results indicate that increasing the coating amount and extending the polymerization time could improve the mechanical strength of mortar.Increasing the initiator dosage first increased and then decreased the mechanical strength of mortar.Increasing the content of BMA in monomer,the trend of flexural and compressive strength changes in the opposite direction.So that the compressive to flexural ratio of mortar decreases and toughness increases.Analysis of the microstructure of mortar before and after polymer impregnation indicates that polymer impregnation closes the pores and cracks of mortar,improves the interface strength,and forms a reinforcement network in any direction,thus enhancing the mechanical strength of the mortar.（3）Water absorption and quick freezing test of polyacrylate impregnated mortar were carried out.The cumulative water absorption under different water absorption time,the quality and compressive strength after freeze-thaw cycles,and the microstructure before and after freeze-thaw were obtained.The results indicate that the polymer impregnation treatment reduces the water absorption capacity of mortar and delays the development of freeze-thaw damage.（4）Based on the indoor rapid carbonization test,the change law of carbonization depth and carbonization coefficient of polyacrylate impregnating mortar and the influence of carbonization on its microstructure were analyzed.The results indicate that the polymer impregnation treatment can reduce the carbonation development rate of mortar.The polymer film hinders the reaction of CO2 with hydration products.（5）The chloride migration coefficient of polyacrylate impregnated mortar was determined by RCM method.The chloride ion natural erosion test was carried out to test the free chloride ion content in mortar and the microstructure after erosion.The results indicate that the chloride migration coefficient decreases significantly after polymer impregnation.The free chloride content only has a relatively high distribution in the shallow layer of mortar.The dense microstructure confirms its excellent resistance to chloride ion erosion. |
