Study On Preparation And Properties Of R-PET-based Unsaturated Polyester Resin Concrete

Unsaturated polyester resin concrete is an ideal replacement of cement concrete for application on drainage due to the advantages of high strength,excellent chemical corrosion resistance and aesthetics.In this paper,the unsaturated polyester resin derived from r-PET was employed as binder,crushed granite as aggregate,calcium carbonate as filler,and KH560 as coupling reagent,the r-PET-based unsaturated polyester resin concrete was prepared.Non-isothermal DSC was used to study the curing kinetics of the unsaturated polyester resin.the determination of compressive strength,flexural strength,chemical resistance feature,dynamic thermodynamic,and nanoindentation were carried out.The microstructure of the composite was observed by SEM.Experimental results show that though the cohesive action of r-PET-based unsaturated polyester resin binder on inorganic materials is poor,the flexural strength and compressive strength of the resin concrete can be greatly improved by introduction of some active coupling agent.The flexural strength and compressive strength reach at 90MPa and 22MPa respectively for the composite with resin dosage of 16%and KH570 dosage of 0.3%(wt of resin).The values meet the requirements of the EN1443 standard.These suggest that appropriate amount of resin,filler and aggregate can effectively improve the mechanical strength of the resin concrete.The resin concrete with 0.8%wt glass fiber gives 25.04%increment in flexural strength,but 3.29%decrement in compressive strength.Moreover,the presence of glass fiber greatly influences the processing performance of the resin concrete.The compressive strength and flexural strength of the resin concrete with 2%water decreases by 37.12%and 51.30%respectively,indicating that water content of aggregate and packing must be controlled to ensure the mechanical properties of the resin concrete.Non-isothermal DSC method is always used to study the curing kinetics of unsaturated polyester resin,as well as to the curing dynamics of unsaturated polyester resin/inorganic composite.The apparent activation energy for unsaturated polyester resin is calculated to be 58.97 kJ/mol and 61.66 kJ/mol via Kissinger and Ozawa methods,and those for the unsaturated polyester resin/inorganic composite are 49.03 kJ/mol and 52.30kJ/mol respectively.The heat release of unsaturated polyester resin/inorganic composite is found to be two-thirds of that of unsaturated polyester resin,suggesting that the presence of inorganic components decreases the energy barrier for curing reaction of resin,whereas cuases little effect on the crosslinking degree of unsaturated polyester resin.It is also clear that,the coupling agent almost gives no impact on the apparent activation energy of resin concrete.Moreover,the results of dynamic thermodynamic analyses show that the coupling agent improves the interface adhesion stress between the inorganic component and resin.Nano-indentation experiments also show that the presence of coupling agent enhances the interface mechanical strength between resin and inorganic components.