Toughness Properties of Concrete Modified with Water-borne Polyurethane

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 influence of water-borne PUA on workability and mechanical performance of concrete were investigated experimentally. 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 early plastic cracking resistance and 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. And PUA can refine the crack from 2-4mm to 0.2-0.5mm of the main distribution, decreasing total area of crack greatly.