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| Laboratory investigations on the mechanical properties of sandstone in chemical corrosion under and freeze-thawing cycles |
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Abstract The physical and mechanical characteristics of sandstone specimens eroded in different chemical solutions （acidic Na2SO4 solution、neutral Na2SO4 solution and alkaline NaOH solution）and subjected to different freeze-thawing cycles is experimentally studied. The variation of physical and mechanical characteristics of sandstone specimens subjected to different chemical solutions for 30ds and then different freeze-thawing cycles is analyzed. Meanwhile the damage of microstructure of sandstone specimens is observed by means of stereo microscope and SEM scanning electron microscope. The damage variable based on the change of porosity was defined to analyze quantitatively damage degree of sandstone specimens. The test results show that for different chemical solutions，the peak strength and elastic modulus of sandstone specimens decrease by exponential function with the increase of freeze-thawing cycles，but its peak axial strain increases by exponential function with the increase of freeze-thawing cycles. With the increase of freeze-thawing cycles，the damage of sandstone specimens increased gradually soaked in different chemical solutions. The damage degree of sandstone specimens soaked in acidic chemical solution is bigger than that in neutral chemical solution and alkaline chemical solution，that is the smallest under alkaline NaOH solution. Acidic chemical solution intensified the damage and degradation degree of sandstone specimens under freeze-thawing cycles，but there has some mitigative effect on that of sandstone specimens soaked in neutral solution and alkaline solution. Chemical corrosion and together with freeze-thawing cycles can give mutual promotion and mutual influence on the degradation and damage of sandstone specimens.
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Received: 03 August 2016
Published: 28 December 2017
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2017, Vol. 38 
