| The main factor that affect the aging resistant performance of epoxy structural adhesive and its aging mechanism are discussed in this paper. On this base, the appraisal method of the aging resistant performance is researched by test. Compared the result between wet-and-heat aging test and boiling aging test, establish a relationship between the wet-and-heat aging time and boiling aging time. The effect of the different curing systems on the aging resistant performance of epoxy structural adhesive is researched chiefly by boiling test, and get the effective modify method for aging resistant performance of epoxy structural adhesive, the result show that:There is not obvious difference in the affect on aging resistant performance of epoxy structural adhesive between wet-and-heat aging for 90 days and boiling aging for 7 days in different curing systems. So the boiling aging test can be used to choose the optimized formula quickly. The boiling aging test shortens the test period and has significant application value in engineering.The curing agent has decisive affect on aging resistant performance of epoxy structural adhesive. In the condition of this paper, the aging resistant performance of aromatic amine curing agent is worst, polyamide curing agent and aliphatic curing agent is better, Alicyclic amine curing agent is best.The epoxy structural adhesive has different property in different curing agent. In this paper, polyamide curing agent or aliphatic curing agent has good mechanical performance and bad aging resistant performance, Alicyclic amine curing agent has good aging resistant performance and bad mechanical performance. Using any of them separately can not meet the demand for aging resistant performance, mechanical performance and bonding performance in Design code for strengthening concrete structure.Both of the two kinds of Alicyclic amine curing agents can improve the aging resistant performance of epoxy structural adhesive in polyamide curing system. With the content of Alicyclic amine curing agent increasing, the conservation rate of shearing strength after boiling aging for 7 days increases gradually.Compare with polyamide curing system, polyamide-aliphatic mixed curing system has better mechanical performance. Both of the two kinds of Alicyclic amine curing agents can also improve the aging resistant performance of epoxy structural adhesive in polyamide-aliphatic mixed curing system. With the content of Alicyclic amine curing agent increasing, the conservation rate of shearing strength after boiling aging for 7 days also increases gradually.The modify effect of the two kinds of Alicyclic amine curing agents on the aging resistant performance of epoxy structural adhesive is distinguishing. Considering the aging resistant performance, mechanical performance and economic performance together, when mix polyamide-aliphatic mixed curing agent B6 and Alicyclic amine curing agent B4 in proportion of 90 to 10, the epoxy structural adhesive has good combination property, the steel-steel shear strength is 27.2MPa, the conservation rate of shearing strength after boiling aging for 7 days is 98.5%, the tensile strength is 50.1MPa, the compressive strength is 91.5MPa.The silane coupling agent can improve the aging resistant performance of epoxy structural adhesive obviously, there is difference when use different variety silane coupling agents or different processing methods.In the test of this paper, the modify effect of cement, nano-SiO2, nano-CaCO3, organic montmorillonite on aging resistant of epoxy adhesive is not obvious. The modified epoxy structural adhesive has good aging resistant performance and mechanical performance, meet the application demand in engineering. The simple and advisable modify technology has significant application value in structural strengthening engineering. |
