2.2.7. Chemical Attack Resistance

The granite and ASPU resistance to chemical attacks determination was performed according to a Brazilian standard NBR 13818 Annex H adaptation [25]. Sixteen specimens of each stone were used, four specimens for each reagent, namely: ammonium chloride, hydrochloric acid, citric acid and potassium hydroxide. Table 2 shows the reagents concentration and exposure time used according to the standard [25]. The specimens were weighed before and after the chemical attack in order to measure the weight loss.


**Table 2.** Concentration and time of exposure of chemical attack agents.
