Application of Photocatalytic Concrete Paving Blocks in Poland—Verification of Effectiveness of Nitric Oxides Reduction and Novel Test Method

Abstract

Photocatalytic concrete is one of the most promising concrete technologies of the past decades. Application of nanometric TiO2 to cement matrices enables the reduction of harmful airborne pollutants. Although a number of implementations of this technology are described in this paper, problems related to test conditions are also reported. One major issue is the sufficient light irradiation that for higher latitudes can be significantly reduced. In this paper, a field campaign on the implementation of photocatalytic concrete pavement in Warsaw (52.23° N) is briefly described. Based on experience from the field campaign, a novel test method is developed. In the research, the effectiveness of nitric oxide reduction is verified at natural light irradiation for various dates of solar position at noon in central Poland (51.83° N). The results confirm the benefits of using photocatalytic materials at higher latitudinal locations. The experimental setup presented in the study combines the advantages of controlled measurement conditions typical in laboratory tests with the possibility of including natural sunlight conditions in the investigation process.

Photoactive Cements: A Review

“…It is influenced by many environmental factors, such as latitude, temperature, humidity, type of soil, amount of rain, the way in which rainwater washes the building, wind speed, its direction, UV wavelength range, etc. [ 33 , 167 , 168 , 169 , 170 ].…”

“…Thus, field tests were conducted not only for tunnels, but also for horizontal applications. Witkowski et al [ 167 ] presented the results of field studies on the use of photocatalytic cobblestones in Warsaw to reduce NOx pollution. The studies on a larger scale were preceded by laboratory experiments in which the effectiveness of NOx reduction was proven in accordance with the UNI 11247 standard [ 173 ].…”

“…Concentrations of NO, NO 2 , and NOx were measured on a pavement with conventional concrete paving stones and on a photocatalytic paving stone (catalyst embedded only in a five-millimeter surface layer) both 400 mm above the pavement surface. The mean daily reduction was 31%, which was above the threshold for the target’s large-scale use (15%) [ 167 ]. An important step was the researchers proposing an innovative research method that used light conditions and gas flow that most faithfully reflected real conditions.…”

“…An important step was the researchers proposing an innovative research method that used light conditions and gas flow that most faithfully reflected real conditions. Moreover, the test configuration [ 51 , 167 ] reduced the negative influence of wind and insufficient concentration of pollutants, as in Folli et al [ 174 ]. In Denmark, on the central street of Copenhagen, near the Central Station, one hundred meters of pavement is made of unmodified concrete blocks and the other is made of 100 m of modified titanium dioxide.…”

The Potential Risk of Nanoparticulate Release from Photocatalytic Pavement Concrete Surface Due to a Simulated Abrasion Load—An Experimental Study

“…The most investigated photocatalyst in the construction industry has been titanium dioxide (TiO 2 ). Photocatalytic cementitious materials with nanometric TiO 2 have already been used in many civil and building applications, such as tunnels [ 7 , 8 , 9 ], concrete facade elements [ 10 , 11 , 12 , 13 ], and concrete pavements [ 14 , 15 , 16 , 17 , 18 ].…”