The Paper presents a constitutive model for describing the stress-strain behaviour of partially saturated soils. The model is formulated within the framework of hardening plasticity using two independent sets of stress variables: the excess of total stress over air pressure and the suction. The model is able to represent, in a consistent and unified manner, many of the fundamental features of the behaviour of partially saturated soils which had been treated separately by previously proposed models. On reaching saturation, the model becomes a conventional critical state model. Because experimental evidence is still limited, the model has been kept as simple as possible in order to provide a basic framework from which extensions are possible. The model is intended for partially saturated soils which are slightly or moderately expansive. After formulating the model for isotropic and triaxial stress states, typical predictions are described and compared, in a qualitative way, with characteristic trends of the behaviour of partially saturated soils. Afterwards, the results of a number of suction-controlled laboratory tests on compacted kaolin and a sandy clay are used to evaluate the ability of the model to reproduce, quantitatively, observed behaviour. The agreement between observed and computed results is considered satisfactory and confirms the possibilities of reproducing the most important features of partially saturated soil behaviour using a simple general framework. L'article présente un modèle constitutif pour décrire le comportement contrainte/déformation des sols partiellement saturés. Le modèle est formulé dans le cadre de la plasticité qui s'endurcit, en uti-lisant deux jeux indépendants de variables de contrainte, c'est-à-dire l'excès de la contrainte totale sur la pression de Pair et la succion. Le modèle peut représenter d'une façon logique et unifiée beaucoup des caractéristiques fondamentales du comportement des sols partiellement saturés qui avaient été traités séparément dans des modèles proposés précédemment. Lorsque la saturation est atteinte le modèle devient un modèle conventionnel d'état critique. Comme les données expérimentales restent encore limitées, le modèle d'été simpliné le plus que possible, afin de fournir un cadre de base à partir duquel des extensions sont possibles. Le modèle convicnt à des sols partiellement saturés qui sont expansifs à un degré faible ou modéré. Le modèle est d'abord formulé pour des états de contrainte isotropes et triaxiaux. Puis l'article décrit des prédictions typiques et les compare de façon qualitative avec des tendances caractéristiques du comportement des sols partiellement saturés. Les résultats de quelques essais régis par la succion eftectués dans le laboratoire sur du kaolin compact et sur une argile sablonneuse sont utilisés afin d'evaluer la capacité du modèle de reproduire de façon quantitative le comportement observé. On considère que les résultats observés et calculés s'accordent bien et qu'ils confirment les possibilités de reproduire les caractéristiques les plus importantes du comportement des sols partiellement saturés par l'utilisation d'un cadre général très simple.

Life cycle impact assessment (LCIA) is one of basic steps in life cycle assessment methodology (LCA). This paper presents a comparative study of the LCIA of different life cycle inventories (LCI) for EU cements. The analysis unit used is the manufacture of 1 kg of cement, from “cradle to gate”. The impact categories considered are those resulting from the manufacture of cement and include greenhouse effects, acidification, eutrophication and summer and winter smog, amongst others. The results of the study highlighted some inconsistencies in existing inventories. As for the LCIA, the main environmental interventions related to cement manufacture were classified and characterised and their effect on different impact categories analysed. Differences observed in evaluation of the impact of cement type were essentially related to their clinker content.

Decision support tools based on multi-attribute analysis involve the use of different types of variables. These variables are aimed at providing a framework that allows preferences to be quantified. This is particularly useful in the field of sustainability, where variables with different units are involved. One widely accepted framework for standardizing different units is the value function. Studies of value function are complex and frequently have limited physical meaning. In this context, this paper emphasizes the need to define a general equation that reflects the preferences of the decision maker in a clear and easily applied way. The paper proposes a new general equation that fulfils these requirements. By modifying certain parameters, this general equation represents the most commonly used relationships (linear, convex, concave and S-shaped). The proposed equation is finally applied to four variables used in the field of industrial buildings and sustainability.

Life cycle inventories (LCIs) are a prerequisite of life-cycle assessments (LCA). This paper conducts a comparative analysis of inventories of several different types of cement produced in Europe. It considers the production of 1 kg of cement from cradle to gate, and all results are based on this mass unit. The reliability of cement inventories is affected by inaccurate or nonrepresentative data, and comparative analysis is difficult due to varying system boundary definitions. Only the four main emissions (CO 2 , NOx, SO 2 and dust) are considered. The theoretical model used gives reasonable estimates of emission levels and, thus, can serve as a reference to measured values. In the case of CO 2 , this is definitely a feasible alternative to in situ measurements. The emissions derive primarily from the production of clinker, both from the chemical reactions occurring in the kiln and by its fossil fuel consumption.