Improvement of indoor air quality using photocatalytic cement-based mortars

Recent European laws and directives are stricter in terms of energy efficiency of buildings. Constructions are currently built up more sealed and there is not enough air changing. This condition leads to a greater risk of unhealthy indoor environments. Mortars, plasters and finishings can have an active role to improve indoor air quality. In this research five different mortars, with water/cement = 0.5 by weight and aggregate/cement = 3.5 by volume, are manufactured using different aggregates. Conventional aggregate is compared as reference with unconventional aggregates with large specific surface and high porosity, substituted by volume. The binder is a photocatalytic white cement with TiO2, potentially able to decompose the adsorbed pollutants. Mortars are characterized in terms of fresh and hardened properties. The results show that mortars prepared with unconventional aggregates have lower, even still acceptable, mechanical performances with respect to reference one. However, they show better permeability and moisture buffering capacity. Depollution properties are evaluated with the adsorption capacity of Volatile Organic Compounds. Mortars manufactured with unconventional aggregates show a depollution capacity up to two times higher with respect to that of conventional sand. The addition of UV irradiation positively influences depollution capacity even in presence of conventional aggregate.