Research On Mechanical Behavior Of Inorganic Polymer Concrete Filled Steel Tubular Columns Under Eccentric Load

With the growing seriousness of resource shortages and environment pollutionand the frequent occurrence of natural disasters, the materials’ researches andapplications of energy conservation, environmental protection, rapid repair andconstructions had been increasingly focused on. Having the characteristics of rapidhardening and early strength, energy conservation and environmental protection,inorganic polymer concrete commonly had been used in the road rapid repair andengineering construction. And the researches to solve the poor shrinkage resistanceand carbonation resistance of inorganic polymer concrete also were the hot spots. Inthis paper inorganic polymer concrete filled steel tubular(IPCFST) was formed bycombining inorganic polymer concrete(IPC) and round steel tube, expansion agentwas mixed in inorganic polymer concrete, then the researches on mechanical behaviorof IPCFST columns under eccentric load were processed. The main analysis andconclusions were as follows:1) IPCFST shrinkage experiments were carried out, the shrinkage performancesof IPC in different dosages of expansion agent under the steel pipe constraint wereanalyzed and the optimal dosage of expansion agent was determined. The analysisresults showed that under the steel pipe constraint,3d age’s inorganic polymerconcrete shrinkage value could reach more than half of the total shrinkage. Expansionagent can improve the shrinkage resistance of inorganic polymer concrete, with theaugment of expansive agent, shrinkage reduced gradually. And the optimal dosagewas6%. While the steel elastic modulus, yield strength, ultimate strength, andinorganic polymer concrete3d’s elastic modulus, poisson’s ratio, uniaxial stress-strainrelationship were determined by the relevant tests.2) Experimental Researches on Mechanical Behavior of IPCFST Columns underEccentric Load in3days had been investigated. The influences of the early failurepattern, the mechanism and the bearing capacity of eccentric compression by thedosage of expansion agent and eccentricity were analyzed. The results showed thatthe failure pattern and mechanical behavior of both composite columns were similarunder eccentric load, the bearing capacity of IPCFST columns were higher than CFST; while the bearing capacity and the elastic stage of IPCFST columns could beimproved after mixing the expanding agent and would be lowered as the increasing ofeccentricity. The velocity of the strain and lateral deflection in elastic-plastic stagereduced by EA ratios, the strain and lateral deflection increased by eccentricity.3) Eccentric ultimate bearing capacity value of specimens were calculated byusing three kinds of ordinary concrete filled steel tube design standards, and theapplicability analysis had been processed. The results showed that the CECS28-2012standard was adapted. And ordinary formula of bearing capacity of CFST to a certainextent also applied to IPCFST; but all three didn’t consider the effect of expansionagent to specimen ultimate bearing capacity.4) Finite element simulation analysis had been carried out; the eccentric ultimatebearing capacity and load-deflection curve were analyzed and compared with theexperimental results. The results showed that the finite element simulation methodwas feasible, ordinary concrete three-axial constitutive relation also was applicable toIPC.