# Life Cycle Assessment of Concrete Pavement Rehabilitation: A Romanian Case Study
## 4 Results
### LCA with GaBi
#### 4.1.4 The Negative Impact on the Environment
In terms of road, rail, sea, and air, the transport infrastructure is influenced by the manifestations of extreme weather events, heat waves, heavy snowfalls, storms, floods, increasing slope instability, and the changing geophysical properties of the Earth. Therefore, the design of an adequate infrastructure has an extremely important role in minimizing the causes of global warming. In the case of the current study, according to Table 6, we found that the reinforcement of the pavement structure without a geocomposite (first alternative) was the most efficient from this point of view. In Figure 5, we can see more synthetically the results of the analysis. Thus, compared to the existing road pavement, the impact of global warming is higher for modernization and reconstruction alternatives. This is mainly due to the chemical processes that occur in the execution of asphalt layers, especially in the construction of a new road. As can be seen, the third alternative has the highest impact with a value of 66%. The first alternative has 12% and the second alternative has 14%, with both having an almost similar impact on global warming, due to the similar pavement structure; however, in the second alternative there is an additional base layer AB2, therefore this alternative has a bigger value. Ozone is a colourless gas that is composed of three oxygen atoms. It is found in the stratosphere, more precisely between 20-30 km above the Earth, where it protects the surface from dangerous ultraviolet (UV) rays. For its measurement, the Dobson [38] unit is used, which is equal to 0.001 atm-cm. According to information published by NASA, the total ozone layer measures 300 Dobson units. A decrease in the number of Dobson units in the ozone layer means less protection against ultraviolet radiation. The causes of this can be chlorine, in the form of table salt; bromine, in various treatments; chlorofluorocarbons (known as Freon), which are used as refrigerants; and smog, created by nitrogen oxides produced by cars, power plants, factories. According to research in recent years, the ozone hole above Antarctica has begun to close, which means that ozone is below 220 Dobson units [39; 40]. Concerning the road transport infrastructure, pollution caused through transport has a significant effect on the formation of the ozone hole. The infrastructure of a metropolis-type city leads to increased air pollution and increased noise. This is why the inhabitants of big cities want to move out of town, and so they generally use personal cars to get to work. This factor leads to increased pollution and ozone depletion. The current study is important for obtaining the protection of the ozone layer as much as possible, as well as the increased air quality. According to Table 7, the first alternative (reinforcement of the pavement structure) is the most efficient from this point of view. Figure 6 shows more synthetically the results of the analysis. Here, can be observed that the third alternative is the most unfavourable, with an impact of 45% and its value being approximately equal to the total emissions given in the existing road pavement with 14% impact, and the first alternative having 19% and the second alternative having 22%. This is caused by the production and disposal of nitrogen oxides during new road construction. The first alternative requires the smallest labour force, which means that this variant produces the smallest amount of nitrogen oxide, but it is also more favourable in terms of the stratospheric impact of ozone. Figure 5: Global warming potential.