Research on working performance of waterborne aliphatic polyurethane modified concrete

A waterborne polyurethane with relatively lower cost and higher solubility in water was adopted to improve the performance of ordinary concrete. The waterborne aliphatic polyurethane modified concrete (WPMC) was prepared by waterborne aliphatic polyurethane, cementitious materials, coarse and fine aggregates, polycarboxylate superplasticizer and foam stabilizer. Then, a series of experimental research and theoretical analysis were carried out to investigate the mechanical properties, durability and microstructure of WPMC. The appropriate content of waterborne polyurethane increased elastic modulus, compressive strength, splitting tensile strength and flexural strength of WPMC. A significant correlation was found between the splitting tensile strength or elastic modulus and compressive strength of WPMC. Furthermore, it could effectively improve the chloride penetration resistance and impermeability of concrete after the waterborne polyurethane was added. Also, the freezing and thawing resistance was enhanced. The improved formula was proposed to predict the capillary water absorption of concrete at any time. MIP and SEM test results showed that the microstructure of concrete was improved after adding waterborne aliphatic polyurethane. Finally, the PCA method was utilized to analyze the optimal polymer-cement ratio of WPMC. The conclusion was that 0.0044 was the better polymer-cement ratio. The findings demonstrate that it can improve the mechanical properties, durability and microstructure of the concrete after adding appropriate content of waterborne aliphatic polyurethane.