Production of wall bricks with infills and comparison of thermal conductivity coefficients

Because of depletion and the resultant decrease of global energy resources, along with the ongoing arduous search for alternative energy sources, a sincere effort is also being put worldwide for frugal and economical usage of the existing energy sources. In developed countries great care is given for thermal insulation of dwelling structures, which is mainly related to the materials used, and the relevant standards and regulations are continuously being updated. Wall brick units are the widely used materials for the outer walls. These wall bricks, which are commonly produced using the light-weight pumice aggregates, have hollow parts of various patterns. In this study, wall bricks of thicknesses of D = 100, 150, 200 mm, having various hole configurations produced by commercial firms, whose plants are certified by the Turkish Standards Institute, are used. In the first phase of the study, the gross unit weight, compressive strength, and thermal conductivity peculiarities of the reference specimens are determined by experiments in compliance with the relevant standards. In the second phase, the same peculiarities of the modified specimens, whose hollow parts are filled separately by perlite and diyatomite mortars mixed using plaster of Paris, are determined. In the third phase, the same peculiarities of other specimens, which are produced by adding perlite to the concrete as an aggregate at three different dosages of 20, 25, 30 kg/m3, and separately adding diyatomite to the concrete as an aggregate at three different dosages of 20, 30, 40 kg/m3, are determined. Wall elements of dimensions of 500 ? 500 ? D mm are formed using all these wall bricks including the original reference units and using ordinary masonry plaster, and their thermal conductivity coefficients are experimentally measured by a hot-plate set-up which is in compliance with the relevant standards and the values are compared. Next, using the package program ANSYS, these wall elements are modeled by the finite-element method and the heat transfer peculiarities at the steady state are analyzed. In conclusion, along with an average drop (improvement) of 25% in thermal conductivity coefficient with the wall bricks whose hollow parts are filled by perlite and of 20% with those bricks whose hollow parts are filled by diyatomite is observed. With the other bricks produced by either perlite or diyatomite added directly to the concrete, the best result is obtained with perlite used at a dosage of 25 kg/m3 and closely with diyatomite at a dosage of 30 kg/m3.