Abstract: Process for production of acid and high temperature resistant cement composites, where the matrix is alkali activated F fly ash alone, F Fly ash combined with ground slag or ground slag alone. F-fly ash produces lower quality alkali activated cement systems. On the other hand the lack of calcium oxide results in very high resistance to medium and highly concentrated inorganic or organic acids. The high strength and low permeability of pure F-fly ash cement systems is achieved by using in the composition un-densified silica fume, the amorphous silicone dioxide obtained as by products in production of ferro-silicones. Precipitated nano-particle silica made from soluble silicates and nano-particle silica fume produced by burning silicon tetra chloride in the hydrogen stream.

Abstract: The invention relates to a light weight structural element, in particular in the shape of a panel, especially for building construction, containing a support structure. The light weight structural element contains at least two supporting rods, which at their ends are interconnected by cross-bars. Between the supporting rods and the cross-bars may be a core; wherein the surfaces of the supporting rods are interconnected by an adhesive skin made from a material of a thickness between 0.5 and 5 mm. The invention also relates to the construction technique of constructing buildings using the light weight structural elements.