The electrochemical and corrosion protective properties of electrochemically deposited thin films of polypyrrole (PPy) have been studied. Two systems have been investigated: (1) Oxalate-doped PPy; and (2) a dual layer system consisting of PPy-oxalate and PPy-poly(styrene sulfonate). Large anions like PSS are interesting, because they possibly prevent ingress into the layer by halide ions like chloride. Open circuit potential measurements and impedance spectra of both systems are compared. For intact coating systems the impedance spectra of the four systems investigated can be described by an equivalent circuit model consisting of an R f Q f circuit, due to the polypyrrole film itself, and a modified Randles circuit in series, to account for the double layer at the polypyrrole/ electrolyte interface and the polypyrrole reaction. In 0.1 M NaCl the time to failure for the dual layer is almost 6-fold that of the single layer. This indicates that PSS is indeed capable of preventing the ingress of chloride ions. In 0.1 M Na 2 SO 4 the time to failure for the dual layer is less than double that of the single layer.

Adobe is an ancient building technology made of sun dried bricks joined together by mud mortar. This paper deals with the physical and mechanical characterization of three different typologies of adobe bricks and one typology of mud mortar produced in Europe. They differed in terms of internal soil element proportions and amount of organic content. Physical tests consisted of granulometry, moisture content and density tests. The mechanical characterization consisted of uniaxial compressive tests and three point bending tests. Tests were performed according to modern material standards. The main mechanical properties both in tension and compression were determined at different curing conditions. The outcome provided in this study offers a general overview on the assessment of the mechanical performance of adobe in relation to the properties and interactions of its soil constituents. In fact, the comparison between components with the same soil mineralogical family and production process made it possible to assess both at a qualitative and quantitative level the effect of the physical properties of the mixture (such as fiber and clay percentages or moisture content) on the mechanical parameters of the resulting bricks and mortar. This paper proposes new predictive formulations of the most relevant material parameters in strength and deformation, such as compressive strength, deformation at peak stress and ultimate displacement for both adobe bricks and mortar. They quantify the influence that water content, clay percentage and fiber reinforcement produce on the mechanical performance of the tested adobe components. This was made possible by means of multivariate statistical analyses on the mechanical parameters derived from all the tested samples.

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