Experimental Study For Cement Mortar's Mechanical Capability Under Environmental Erosion

Because of the long-term action of corrosion,the cement mortar decreases its durability and damages in advance.On the basis of summed up the international and domestic research,compressive strength and constitutive relation to cement mortar is discussed.The study mainly includes:First,compression strength of the cement mortar that is salt corrosion have studied. Have considered the effect of corrode mediator of NaHCO₃ and Na₂SO₄ on cement mortar, the compression strength of corroded cement mortar on the effect of four concentrations of corrode liquor is tested,such as 0.01 mol/L,0.05 mol/L,0.1 mol/L,0.5 mol/L corrode and so on.The results show that the compression strength of cement mortar is different in the two kinds of corrode liquor.With the increasing time of corrode,the compression strength of cement mortar fall down gradually in NaHCO₃.But in Na₂SO₄,it arises when the concentration are 0.01 mol/L and 0.05 mol/L,and when the concentration is 0.1 mol/Land0.5 mol/L,strength fall down quickly.Secondly,Mechanical property of corroded cement mortar that is corroded by Hydrochloric Acid solute with pH value of 2.5,4.5,8 and 12 is studied.The results show that the compression strength of cement mortar falls down with time and concentration linearly.It also shows that stress-strain curve of the corroded cement mortar become moderate gradually with the severe of the cement mortar,but the shape of the curves are very similarly.Based on the experimental results,a calculative model is put forward to compute the compressive strength of corroded cement mortar.Compared with the computation results and the experimental results,the calculative model is very accurate, and it is applicable for predicting the cement mortar in the acidic environment.Finally,cement mortar corrosion effect due to freeze-thawing cycles is discussed. Compression strength of the cement mortar is text under freeze-thawing cycles in 0,5,30, 60,90 times.Result shows the compression strength of cement mortar falls down with times under freeze-thawing linearly.A calculative model and a constitutive model are put forward to compute the compressive strength of corroded cement mortar.Calculation model result accuracy is higher,can be put into use in actual project.