Bogdan Cazacliu

Sensitivity Analysis of Environmental Process Modeling in a Life Cycle Context: A Case Study of Hemp Crop Production

The aim of this article is to develop a methodological approach allowing to assess the influence of parameters of one or more elementary processes in the foreground system, on the outcomes of a life cycle assessment (LCA) study. From this perspective, the method must be able to: (1) include foreground process modeling in order to avoid the assumption of proportionality between inventory data and reference flows; (2) quantify influences of foreground processes’ parameters (and, possibly, interactions between parameters); and (3) identify trends (either increasing or decreasing) for each parameter on each indicator in order to determine the most favorable direction for parametric variation. These objectives can be reached by combining foreground system modeling, a set of two different sensitivity analysis methods (each one providing different and complementary information), and LCA. The proposed method is applied to a case study of hemp‐based insulation materials for buildings. The present study will focus on the agricultural stage as a foreground system and as a first step encompassing the entire life cycle. A set of technological recommendations were identified for hemp farmers in order to reduce the crops environmental impacts (from –11% to –89% according to the considered impact category). One of the main limitations of the approach is the need for a detailed model of the foreground process. Further, the method is, at present, rather time‐consuming. However, it offers long‐term advantages given that the higher level of model detail adds robustness to the LCA results.

Historical Rammed Earth Process Description Thanks to Micromorphological Analysis

ABSTRACT Rammed earth was traditionally used in western European countries before industrial building materials replace it during 20th century. Construction strategies developed by former builders were dictated by locally available construction materials and engendered local constructive cultures. Unfortunately, this knowledge was orally transmitted and is lost today. The rediscovery of these cultures can provide answers to modern rammed earth construction processes. Micromorphological analysis of earth walls provides information to rediscover traditional rammed earth process. This methodology is applied for the first time, on a rammed earth wall of a farm located in Bresse (France). Thanks to this methodology, pedological horizon, extraction depth, and location of the material source are identified. The surface area excavated for the construction of the building is estimated. Micromorphological study gives information on mixing degree and water content at implementation time. Strain features associated with ramming effect and rammed earth boundary layer are also highlighted.

Influence of asphalt composition upon the thermodynamics performance of a mixing plant

Pavement material production requires a highly intensive energy processing related to the drying and the heating of granular materials within a rotary kiln. Thus, a better prediction of thermophysical parameters of bituminous concrete materials during their transformation is required to improve the processes in order to reduce their environmental impact. The present paper deals with accurate thermodynamics balance in a mix-asphalt plant. We report input and output mass flows captured within an instrumented flight rotary kiln devoted to a large range of asphalt materials. Hot-mix (Tmaterials ∼170°C), warm-mix (Tmaterials ∼120°C) and Recycled Asphalt Products (so-called RAP) are compared. Computation of the macroscopic energy balance exhibits an averaged energy flux source equal to about 7 MW, the major amount being connected to the power gas burner. The heat sink related to the drying is different according to the formulation, RAP particles having non-negligible moisture content. In situ temperature sensors are used to validate an advanced thermodynamics model involving RAP feeding rate. The thermal degradation of the RAP particles emphasises significant heat release measured at the RAP injection position which is captured by the theoretical model.

Usage of air jigging for multi-component separation of construction and demolition waste

The use of air jigging for performing multi-component separation in the treatment of mixed construction and demolition waste was studied. Sorting tests were carried out with mixtures of equal bulk volume of concrete and brick in which fixed quantities of unwanted materials - gypsum, wood and paper - were added. Experimental results have demonstrated the possibility to use air jigging to carry out both the removal of low-density contaminants and the concrete concentration in only one process step. In relation to the removal of contaminants only, the overall performance of jigging process can be comparable with that of commercial air classifiers and automatic sorting systems. Also, the initial content of contaminants seems does not have a significant effect on the separation extent. These results are of particular importance for recycling plants processing as they represent an alternative to optimize the use of air jigs. Further investigation is needed in order to evaluate the practical feasibility of such method.