Effect of immersion in acid solutions on the physico-mechanical properties of a porous limestone

Carbonate rocks are widely used as building material due to their availability and attractive appearance. However, their durability can be compromised when exposing to acidic environments like those generated by acid rain, biological agents or industrial sewage. This study investigates the impact of immersion in acidic aqueous solutions prepared from hydrochloric acid on the physico-mechanical behaviour of a porous limestone from Spain. For this purpose, its physical and mechanical properties were determined in intact state and after immersion for one month in solutions with pH values of 2, 4 and 7. The results revealed that the exposure to high-acid solution changes the colour, significantly increases the porosity and absorption, and reduces the ultrasonic wave velocities, uniaxial compressive strength and elastic modulus of the limestone. These findings can serve as reference to make decisions about the use of this geomaterial in construction and heritage restoration works performed in acidic aqueous environments.