Evaluation of optimal replacement of natural aggregates by recycled concrete aggregates to achieve sufficient durability

The use of recycled concrete aggregate (RCA) is one way to reduce the depletion of raw materials for the production of concrete. In this article RCA was tested and evaluated. Concrete with 25 to 80 % of RCA was examined in terms of its durability performance, particularly capillary absorption and shrinkage. Capillary absorption testing showed that RCA has better or identical results as the reference mixture. Concrete with a high proportion of RCA had reduced durability, even with reduced durability the concrete maintains all the requirements of the Norwegian Standard. RCA as partial replacement in smaller quantities show good properties

MEE (Materials Engineering for Electronics) - Aim, Tools and Perspectives

New approach to solidification processes based on a combination  of mechanical vibrations and on specially introduced magneto-hydrodynamic forces is illustrated on GaSb grown from Ga and Sb solutions. Process is accelerated approximately 20-times compared with "classical" Travelling heater method - solution growth. Up to now, though ingots possess mosaic texture, their transport properties: μH = 3.800 cm2/Vs, p = 1.7 . 1017 at 77 K are slightly better than published results. A schematic arrangement of the growth apparatus for a modified travelling heater method, and of the growth conditions are given. A simple calculation of levitation phenomenon being generated by a controlled MHD forces are presented. There is brought a brief analyses of this phenomenon for an application on the above mentioned processes. Some experimentation attempts are added. Possible perspectives inhering in this peculiar process can also inspire young investigators/scientists