Solid State Phenomena Vol. 325

Abstract: The article deals with the influence of crystallization additives on the life of self-compacting concrete (so-called SCC concrete), which are exposed to chemically aggressive environments. The focus is not only on the effect of the crystallization additive on the characteristics of the capillary-pore structure of SCC concrete, but especially long life durability of self-compacting concrete (two years expozition). The effect of individual types of aggressive environment is assessed on the basis of a set of physico-mechanical and physico-chemical analyzes.

Abstract: This paper deals with the development of a new mortar, for cement-based inverse grouting, with an increased degree of chemical resistance. The aim of this work is to verify new mixtures optimized by suitable secondary raw materials. The studied parameters include selected physical-mechanical characteristics and chemical resistance of individual raw material variants is characterized by resistance to sulfate solution. The results of this work show that it is possible to increase the chemical resistance by optimizing the grouting mortar mixture with suitable secondary raw materials. The optimized mixture for the new grout will be part of a comprehensive material system for the remediation of sewers or shafts.

Abstract: In the course of the repair and fire protection upgrading of an approx. 1100 m long road tunnel in Hamburg, the eleven crossings of fire protection channels were covered with sheet steel to prevent the nesting of pigeons. In this context, the mechanical strains that may occur in the event of a fire had to be determined. In particular, it was necessary to clarify which mechanical loads would result from relative movements between the substrate (fire protection board) and the cover sheets due to their different thermal expansion in case of fire. For this purpose, the thermal behavior of the CSH fire protection board was determined by means of simultaneous thermal analysis and dilatometry, and the mechanical and thermal behavior of the composite construction was studied. The studies revealed that due to the facts that thermal expansion of the both materials and due to the softening of the fire protection panel the restraint that is generated by the screwed-on perforated plate in the vicinity of the screw shafts remains low during thermal loading. As a result, the top plate does not crack or break off, which means that screwing on the perforated steel sheets not negatively affects the fire protection of the panels.