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International audienceDuring the last 30 years, lightweight concretes (LCs) have been developed in order to decrease the volume of load-bearing components, reduce the consumption of raw materials and obtain better thermal properties than those of conventional concrete. Several production processes can be employed. Lightweight aggregates can be used to decrease the density (lightweight aggregate concrete) or gas can be introduced by various methods (foam concrete (FC)). A wide range of properties can be achieved depending on several parameters (production process, binder choice, water/cement mass ratio, porous structure, admixture or surfactant content etc.). This paper reviews the influence of these parameters on the compressive strength and thermal conductivity of FC, bringing the information together in two overview graphics. Special attention is paid to LC made with calcium sulfate (gypsum) binders. This study shows that the gypsum lightweight materials present acceptable thermomechanical performances

International audienceThis paper focuses on investigating the bonding fatigue performance between two asphalt concrete (AC) layers. For purposes of this experimental campaign, a customised double shear testing device was designed. Two interface conditions have been analysed herein: with and without a tack coat. Moreover, the corresponding fatigue behaviour has been analysed at two temperatures: 10 °C and 20 °C. As expected, the absence of a tack coat leads to a decrease in bonding fatigue performance. Since fatigue tests are highly time-consuming, a method that allows predicting the conventional interface fatigue law from accelerated shear fatigue tests has been proposed. Other novel findings on interface fatigue behaviourwill also be discussed. In addition to these fatigue results, an interface failure model is proposed to evaluate the interface lifetime. Incorporating interface fatigue performance into pavement analysis proves to be a key parameter in describing in situ pavement conditions and assessing pavement durability

International audienceThe mineral foams studied were mainly composed of a reactive, partially anhydrous calcium sulphate (90%) and Portland cement (10%), mixed with a low water-to-binder ratio (W/B =.35) leading to a highly concentrated suspension. The foaming method used allowed a wide foam density range (250 andlt; ρ andlt; 820 kg/m3) to be obtained after hardening and drying, with the same mineral suspension composition. To ensure that foam formed and remained stable until the material had set, six surfactants were chosen. The influence of the surfactants on paste properties in the fresh state was evaluated and the thermal and mechanical performances of gypsum–cement products (foamed and unfoamed) were analysed. The thermal conductivity of gypsum–cement foams evolved linearly with density but compressive strength values were widely dispersed and depended on the porous structure, which was strongly dependent on surfactant type and content. The performance levels of gypsum–cement foams were compared with those of lightweight foam concrete from litterature. The most efficient surfactants and the optimum content range leading to the best thermomechanical compromise were identified. They ensured a minimal compressive strength of 2 MPa, and thermal conductivity lower than.2 W/(m.K). © 2016 Informa UK Limited, trading as Taylor and Francis Group