Paola Di Mascio

Environmental, Human Health and Socio-Economic Effects of Cement Powders: the Multicriteria Analysis as Decisional Methodology

The attention to sustainability-related issues has grown fast in recent decades. The experience gained with these themes reveals the importance of considering this topic in the construction industry, which represents an important sector throughout the world. This work consists on conducting a multicriteria analysis of four cement powders, with the objective of calculating and analysing the environmental, human health and socio-economic effects of their production processes. The economic, technical, environmental and safety performances of the examined powders result from official, both internal and public, documents prepared by the producers. The Analytic Hierarchy Process permitted to consider several indicators (i.e., environmental, human health related and socio-economic parameters) and to conduct comprehensive and unbiased analyses which gave the best, most sustainable cement powder. As assumed in this study, the contribution of each considered parameter to the overall sustainability has a different incidence, therefore the procedure could be used to support on-going sustainability efforts under different conditions. The results also prove that it is not appropriate to regard only one parameter to identify the ‘best’ cement powder, but several impact categories should be considered and analysed if there is an interest for pursuing different, often conflicting interests.

Reliance of pavement texture characteristics on mix-design and compaction process

The surface texture in Hot Mix Asphalt (HMA) pavements has an important role respect to all functional performances: wet and dry friction, rolling noise generation, tire wear, and so on. The texture of a new pavement is a consequence of HMA composition (mix-design) and of construction techniques, especially considering the compaction process. While numerous studies have investigated the effect of mix design on texture, it is still unclear the effect of construction techniques. In this research, some experimental results coming from on-site investigations during the HMA construction, were processed, in order to determine the texture characteristics of pavement surfaces, in terms of mega, macro and micro-texture, using both volumetric and profilometric measures. Furthermore, the asphalt mix composition (grain size, void ratio, bulk density, percentage of bitumen, etc.) were assessed on pavement cores. Some statistical correlations between texture and asphalt mix composition were also carried out. The results confirm that the main influence on the pavement texture level is related to the aggregate maximum dimension, but also the void percentage has a significant influence. The compaction conditions, instead, seem to determine a lower effect, but nevertheless some observations can be deducted. More general, the presented research proposes some considerations, useful to improve the design of mixtures and the compaction techniques of HMA, especially in order to obtain a reduction of rolling noise generation.

New research opportunities for roadside safety barriers improvement

Among the major topics regarding the protection of roads, restraint systems still represent a big opportunity in order to increase safety performances. When accidents happen, in fact, the infrastructure can substantially contribute to the reduction of consequences if its marginal spaces are well designed and/or effective restraint systems are installed there. Nevertheless, basic concepts and technology of road safety barriers have not significantly changed for the last two decades. The paper proposes a new approach to the study aimed to define possible enhancements of restraint safety systems performances, by using new materials and defining innovative design principles. In particular, roadside systems can be developed with regard to vehicle-barrier interaction, vehicle-oriented design (included low-mass and extremely low-mass vehicles), traffic suitability, user protection, working width reduction. In addition, thanks to sensors embedded into the barriers, it is also expected to deal with new challenges related to the guidance of automatic vehicles and I2V communication.