Abstract: In the aim of obtaining the changes in mechanical properties and porosity of sandstone in acid environment, we examined the influences of corrosion time and acid concentration on sandstone’s mechanics properties and porosity through uniaxial compression test on acid-corroded sandstone. Results revealed an apparent corrosion effect on sandstone. The porosity of sandstone soaked in acid solution increased, as reflected by an evident expansion of porosity area in SEM images; the volume of porosity is in positive relation with acid concentration and corrosion time. Moreover, the uniaxial compressive strength and elastic modulus of sandstone deteriorated remarkably after acid corrosion. The uniaxial compressive strength of sandstone corroded by pH = 1 sulfuric acid solution and pH = 3 sulfuric acid solution decreased by 31.59% and 26.99%, respectively, and the elastic modulus reduced by 64.46% and 62.26%, respectively. In addition, the relation between chemical damage variable based on secondary porosity and mechanics parameters was established; the deterioration of mechanical parameters of sandstone is consistent with the change of secondary porosity.

Key words: sandstone, water-rock chemical reaction, porosity, chemical damage, corrosion mechanism, uniaxial compressive strength, elastic modulus