Study On The Elastic Epoxy Resin Adhesive Used For Bridge Deck Overlay

Elastic epoxy resins have been used as bridge deck overlays as a new pavingtechnology. The material is made from flexible epoxy adhesive and wear-resistantaggregate. Because epoxy adhesive has good mechanical properties, weatherresistance, good bonding properties, the epoxy overlay can not only reduce thethickness of the pavement and the dead load, but also has the slip-resistant andcrack-resistant properties, preventing the erosion of the bridge deck by the water andchloride ions. Currently, this technology has been successfully used in engineeringapplications abroad, but it is still in its infancy in china, hence, epoxy o verlaymaterials still need to be imported from other countries. In order to change thissituation, this paper selected the raw material by studying the impact of epoxy resin,flexibilizer, diluents and curing agent for the properties of the epoxy overlay material,and develop a kind of elastic epoxy adhesive used for bridge deck overlay by therecipe optimization of curing agent system, a corresponding construction process wasproposed simultaneously and applied to actual engineering projects. The study resultsshow that:The epoxy resin S4has high tensile elongation and low modulus of elasticity,exhibiting the traits of the elastomer, but its mechanical strength are very low.Moreover, S4is rare and its cost is high, so this material is not widely used. In termsof the tensile properties of the cured product，the Bisphenol A-type epoxy resins S1、S2and the Bisphenol F-type epoxy resin S3are almost the same, although theflexibility of the cured product is not good, but their strength is very excellent.However, under consideration of factors such as performances and costs, the S1andS2are more appropriate.The incorporation of the flexibilizer could improve the flexibility of the curedproduct in varying degrees, such as the increasing breaking elongation and thedecreasing elastic modulus. Although incorporation of the modified polyurethane R3and the epoxy terminal reactive liquid nitrile rubber R4can maintain good tensilestrength, the flexible performance of cured product is still insufficient; therefore, itshould not be selected. The incorporation of the homemade long-chain reactionaliphatic flexibilizer R1and sulfhydryl liquid polysulfide rubber R2can significantlyimprove the performance of the flexibility of the elastic epoxy adhesive, however, the tensile strength and flexibility performance of R1are better than R2, so R1should beselected as the flexibilizer.The diluent can reduce the viscosity of the epoxy system in varying digress. Themonoepoxide diluent has the best dilution performance, but it will significantlyreduce the mechanical properties of the cured product. Dilluet with higher epoxyfunction has lower impacts on the mechanical properties of the cured product. Thelength of the molecular chain segment and the differences in functional groups of thedilluent also can significantly affect the performance of the elastic epoxy adhesive.The diluents with three-epoxy function make the cured epoxy product be able tomaintain high tensile strength and good flexibility. Therefore, it is suitable for thedilution of the epoxy systems.Different types of curing agent have different effects on the performance of curedepoxy adhesive products, and different curing conditions also have different effectson the performance of cured epoxy adhesive products. The toughness phenolicamine-curing agent H5exhibits good tensile strength, and the polyether amine-basedcuring agent H6exhibits good flexibility performance. But single curing agent cannotmeet the requirements of the epoxy adhesive performance. In this paper, the recipeoptimization of curing agent was discussed. The results show that the mixed system ofH1and H5has the most outstanding performance. Therefore, it is appropriate asa curing agent for elastic epoxy adhesive.On the basis of the above studies, according to the requirements of the actualproject, a kind of epoxy overlay material for bridge deck pavement was developed,and the corresponding construction process was proposed and applied to the actualengineering projects. The engineering practice shows that the construction process issimple and feasible. Field test results show that it has good adhesion property withconcrete substrates, excellent slip and wear resistance without increasing the load ofthe deck as expected. Half a year after the road was put into operation, it has beenkept in good condition without delamination, potholes, cracks and other badphenomena.