The Effect Of HEC Interface Agent On The Bond Strength Of The Third Age RCC

In the current project construction,concrete pouring is often interrupted due to various environmental factors,or construction joints are set in the concrete dam according to the construction requirements,or the method of enlarging the cross section is adopted when repairing and strengthening the concrete.The bonding surface formed by various reasons has some problems in the bonding performance of concrete.In order to solve such problems,the interface agent is often used in actual engineering to improve the bonding strength of the bonding surface.However,the interface agent used in most projects is basically cement paste,and the interface agent has a single form,and now the university research interface agent is only for the effect of the bonding strength of ordinary silicate concrete,and there is a lack of relevant research on RCC.Therefore,in this paper,for the RCC,the HEC(High Strength and Water Stability Earth Consolidator,hereinafter referred to as HEC,a high-strength and water-resistant inorganic cementing material)interface agent with different proportions is taken as an example,and here On the basis of this,the design test plan under two different variables of different strength grades of the newly poured RCC and different ages of the old RCC was proposed,and the split-pull test was conducted to obtain the split resistance of the new and old RCC under various influencing factors.The change law of tensile strength,and provide guidance for repair and reinforcement projects according to the law.The research content and conclusions are as follows.(1)The bonding effect of HEC interface agent on new and old RCC is more obvious.Among them,the use of 40%HEC interfacial agent has the largest improvement in the bonding strength of RCC,which is better than the traditional cement paste interface agent.The bonding strength improvement ratio is about 65.3%,and thus It can be concluded that as the amount of HEC interfacial agent increases,its bonding strength also increases.(2)With the new cast rolling to improve strength grade concrete,old and new RCC bond strength also increased,but to a lesser increase in magnitude.(3)The bond strength of new and old RCC has a negative correlation with the age of old RCC,that is,as the age of old concrete increases,the bond strength decreases and gradually stabilizes.(4)Use finite element software to establish new and old roller compacted concrete specimen models,simulate the test process of the split-pull test,obtain a stress cloud diagram,observe the state of its stress distribution,and understand the fracture process more clearly,that is,the maximum stress is generally new At the edge of the bonding surface of the old concrete,the stress gradually decreases from outside to inside along the bonding surface,and is compared with the simulated value based on the test value to verify the rationality of the parameters used in the numerical simulation and the accuracy of the simulated value Sex and regularity.