Exposition to acid attack of mortars with nanosilica, zinc stearate and ethyl silicate coating

Resumen

The demand for durable cementitious materials for applications where they are subjected to aggressive chemical environments is growing. As an example, some infrastructures can be affected by acid attacks, such as sanitation networks, foundations, infrastructures in contact with groundwater or in agricultural and farm facilities. Acid attacks are one of the most severe mechanisms in the deterioration of cementitious materials. The main objective of this study is to compare the physical and mechanical changes of four different mortars subjected to an acid attack (3% w/w of H 2 SO 4 solution). The mortars produced were: i) control mortar; ii) mortar with nanosilica; iii) mortar with zinc stearate; and iv) mortar with an ethyl silicate coating. After 28 days of hardening, the samples were exposed to an acid attack by immersing the specimens in a H 2 SO 4 solution. Physical changes (mass loss, ultrasonic impulse velocity and water absorption) and mechanical changes (compressive strength) were determined after the acid attack exposure. The results show that the lowest mass loss after 90 days of acid attack was observed in the zinc stearate mortar. Moreover, the zinc stearate mortar was also the one that had a lower percentage of strength loss after the acid attack.