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ABSTRACT
Thermal conductivity plays a crucial role in the design of external walls of buildings. This paper is focused on measuring the thermal conductivity coefficient of blocks made of structural lightweight waste aggregate concrete. The concrete mixture contained waste red ceramics fine aggregate and artificial expanded clay coarse aggregate. Replacing conventional aggregates with waste aggregates is one of the possibilities for the sustainable design of concrete construction today. A nondestructive method using the ISOMET 2114 with the surface probe was chosen to determine the thermal conductivity coefficient. Several sets of samples with different mechanical damage rates (0%, 50%, and 100% of ultimate strength capacity) and with different amounts of copper coated crimped steel fibers (0%, 1.0%, and 1.5%) were measured. Each set contained three samples created by cutting the plate to the specific size. The measurement was performed under steady boundary conditions. As the studied material is inhomogeneous, it was necessary to verify how the composition of the concrete under the probe will affect the results. On cutting surfaces, measurements may be affected by the distribution of artificial expanded clay coarse aggregate and fiber reinforcement. Therefore, the effect of probe placement on the measured thermal conductivity coefficients of several samples was determined by detailed measurements. This paper has shown that the increasing amount of fibers caused a slight deterioration in thermal conductivity and that the mechanical damage rate did not have a significant effect on the thermal conductivity of the sample. In conclusion, the results of all samples are compared.
Keywords: thermal conductivity, surface probe, concrete, red ceramic waste aggregate
INTRODUCTION
The replacement of conventional aggregates with waste aggregates complies with the principles of sustainable construction. According to the assumption of sustainable construction, it is appropriate to use not only renewable materials but also recyclable and recycled materials. The use of waste materials, in this case, the replacement of conventional aggregates, is also associated with the depletion of natural aggregate resources. As construction waste represents a high percentage of the total production of all waste, it is advisable to search for its reuse. The use of construction ceramic waste leads to a reduction in the consumption of natural raw materials. A number of studies have been carried out in the past to analyze the...