INCREASE OF FROST RESISTANCE OF CLAY MASONRY UNITS WITH CONSTRUCTION DEMOLITION WASTE ADDITION: A CASE STUDY

This paper fits into Goal 12 of the United Nation Sustainable Development Goals and promotes the green agenda and circular economy demands. The granulated construction and demolition waste (CDW) was added into the raw clay material and laboratory masonry clay elements (hollow block and brick) were extruded, dried and fired. The XRD, DTA, dilatometry, pore size distribution and sieve test were used for material characterization. The influence of CDW addition on plasticity, drying sensitivity as well as green and fired products characteristics and frost resistance of masonry clay units was investigated. The standard EN 772-22 and ASTM C 1167-03 were used respectively as a direct and indirect test method for the evaluation of frost resistance. Results are indicating that the addition of cheap CWD, which is available in large quantities and until now was not used in ceramic masonry industry, can affectively adapt the pore size distribution of the final product and lead to the excellent frost resistance properties at lower firing temperatures. Registered decrease of mechanical properties has not compromised the application of this products in load bearing walls since the compressive strengths were still larger than the limiting one for products intended use.