Research On Shrinkage And Crack Resistance Of HSC Used By Steel Plate Concrete Composite Shear Wall

How to solution steel plate-concrete combine shear wall cracking problem cause of strong restraint and shrinkage is stress and difficult problem in the actual projects.In recent years,various mineral admixtures such as fly ash, ground granulated blast furnace slag,silica fume and concrete admixtures such as expanding agent(EA),shrinkage reducing agent(SRA) and super absorbent polymer(SAP) has been used to solve the cracking problem of HSC,but no systematic study has been done on adding one admixture and double adding,and little-studied has been done on cracking problem cause of high shrinkage stress,so it is very necessary to systematic research on shrinkage and shrinkage cracking problems.The paper presents systematic study on characteristics and influence factors of the concrete strengths, early age shrinkage, dry shrinkage and the trend of plastic cracking,the study content includs that HSC is different from OPC,the influence of water binder ratio(w/b) and mineral admixtures on the concrete strengths, early age shrinkage,dry shrinkage and the trend of plastic cracking,EA,SRA and SAP are tested for reducing the shrinkage cracking problem.The experiment result shows that HSC is more sensitive to concrete strengths, early age shrinkage,dry shrinkage and the trend of plastic cracking than OPC,in the range of 0.2-0.3,the smaller the w/b,the more serious the shrinkage cracking,incorporating with fly ash could reduce concrete plastic cracking, incorporating with blast furnace slag could increase concrete strengths, early age shrinkage and reduce dry shrinkage,when the blast furnace slag substituting 30 percent of cement,the concrete plastic cracking risk is minimum,when silica fume is added to concrete, the concrete strengths, early age shrinkage, dry shrinkage and the trend of plastic cracking is increasing effectively,the plastic cracking risk is maximum when silica fume substituting 8 percent of cement.It was found that EA decrease concrete early strength,increase long-term strength,make early age shrinkage and dry shrinkage lower,but the effect to reducing plastic cracking risk is not well,SRA can reduce early age shrinkage and dry shrinkage and plastic cracking remarkably,but it will reduce concrete strength largely. SAP can reduce early age shrinkage and dry shrinkage and plastic cracking,but SAP is the most detrimental for concrete strength.In the respect of double adding,the SAP and SRA works together best even if both EA,SRA and SAP can reduce shrinkage and plastic cracking,but double adding is more unfavorable to the concrete strength.Several methods have been studied to reduce steel plate-concrete combine shear wall indoor model plastic cracking, blast furnace slag, silica fume, SRA, SAP have been adopt to make the good result,It can solve plastic cracking problem built on guarantee concrete strengths and concrete slump.