In order to reach a specific service life of reinforced concrete structures a certain cover thickness is needed. At present, this is regulated by national standards that also limit the amount and type of supplementary cementitious materials in different exposure environments. The regulations do not, however, consider the actual durability performance of concrete with supplementary cementitious materials. As a consequence, the LCA results might be misleading. This paper shows the environmental impact of concrete with supplementary cementitious materials in chloride environment considering their specific performances. Prescriptive and performance based service life prediction models for chloride ingress are applied and compared. 

A large part of the energy consumption in the European Union member states is related to space heating, a significant share of which is due to transmission losses through the building envelope. Vacuum insulation panels (VIPs), with unique thermal insulation properties, do therefore provide an interesting alternative for the building industry. This paper presents the results of a life cycle analysis (LCA) study that compares the environmental impact of three hypothetical buildings, a standard residential building, a regular well-insulated building and a building insulated with VIPs. The environmental impact includes the global warming potential (GWP) and the primary energy (PE) use, from the material production stage to the building operational phase (50 years). The cradle-to-gate environmental impact categories of ozone depletion potential (ODP), acidification potential (AP) and eutrophication potential (EP) of all building components are also assessed. The study shows a comparatively lower operational energy for the VIP insulated building and a relatively lower total greenhouse gas emission as well as the possibility to save significant living space. The results also show that the VIPs have measurable environmental impact during the product stage while the core material of the VIPs has considerable impact on the results.

Fast and reliable methods for the determination of thermal properties of core materials for vacuum insu-lation panels (VIPs) are needed. It is of great importance to know the thermal performance of a VIP core atdifferent levels of vacuum and external loads. In this study a new self-designed device, consisting of twocylindrical cavities connected to a Transient Plane Source instrument, is used to determine the thermalconductivity of low-density nanoporous silica powders, from atmospheric pressure down to 0.1 mbarwhile applying different levels of external pressure up to 4 bars. The study includes a brief theoreticaldiscussion of methods. The TPS is validated through comparison with available data for commercial silicaas well as through independent stationary measurements with a hot plate apparatus and with a TransientHot Bridge method. The different materials illustrate clear but different trends for the thermal conductiv-ity as a function of the level of vacuum and external pressure. The analysis of experimental results showsthat the transient methods are less suitable for measuring the thermal conductivity of low-density sil-ica powders, especially for the cases when the density is less than a limit at which the heat transfer byradiation becomes dominant compared to pure conduction.

In this study, the pore structure, tapped density and thermal conductivity properties of a new type of nanoporous silica material have been studied. We have applied nitrogen physisorption, high resolution scanning microscopy and Transient Plane Source thermal conductivity measurements to investigate these properties. The new mesoporous silica SNP have large BET surface area, 400-439 m² g^-1 and possess high porosity in the range of 95-97%. The results further show pore diameter centred at 43 nm or 47 nm for the two materials studied. Tapped densities as low as 0.077 g/cm³ have so far been obtained and the thermal conductivity of these materials has been measured to 0.0284 and 0.0294 W (m K)^-1 at room temperature and atmospheric pressure. The effects of tapped density, pore size diameter and particle morphology on thermal conductivity are discussed.

Vacuum insulation panels provide unprecedented possibilities for renovating the existing building stock in a manner that reduces the thermal losses through the building envelope. This study is focused on the implementation of VIPs (vacuum insulation panels) in energy retrofit projects with rendered outer walls. Particular emphasis is put on reducing the thermal bridges due to mechanical fasteners and at the joints of the panels. These are evaluated through a parametric study of the impact of the thermal conductivity of the joints of the panels and the adjacent insulation layer as well as the material of the fasteners. The study is carried out with 3D FEM (finite element method) simulations software. Furthermore, the moisture conditions in the construction are studied. The dynamic moisture behavior of a wall construction is modeled with a two dimensional FEM model. The long term effects of vapor diffusion are investigated in terms of accumulated moisture and the risk of condensation. The results illustrate that vacuum insulation on the outside of the wall construction does not pose a moisture problem to the construction. The simulations are based on a draft of a new technical solution for the refurbishment of a building that is typical for the great Swedish building program of the 1970s.

Vakuumisoleringspaneler erbjuder ett spännande alternativ till traditionella isoleringsmaterial eftersom de kräver endast en bråkdel av isoleringstjockleken. Det finns dock några områden som kräver ytterligare forskning om vakuumisolering ska till fullo kunna användas i byggnader.

This study is concerned with the use of interior air channels in walls for the drying out of surplus water in floor constructions. The floor is to be dried out by the means of an air gap, while a heating cable at the bottom of an adjacent wall channel provides a driving force for the flow. The model of this study can be used to quantify the drying out capacity of such a construction, given the geometrical configuration and the effect of the cable. By posing heat and mass balance equations for a star network equivalent to the delta network of the actual physical problem the temperature and moisture profiles for the floor channel are obtained. The wetted surface of the floor is assumed to be saturated, while the saturated moisture content varies with temperature along the surface. The temperature and moisture distributions along the air gap and the drying out capacity are obtained as a function of the flow rate. The physical problem of the wall channel is posed in terms of the governing equations of conservation. The Boussinesq approximation is used to restrict the variation in density to that of the gravitational force. The buoyancy generated by the cable is related to the frictional forces of the channel walls, providing a relationship between the flow rate and the effect of the cable. The analytical results are compared with laboratory measurements and show good agreement for a number of different heights of the air gap in the floor.