No abstract

The present work examines an innovative manufacturing technique for fired clay bricks, using tuff as a secondary raw material. Samples were made of clay and tuff (0–30 wt.%) fired at 900 to 1100 °C. The chemical and mineralogical compositions and physical and thermal analyses of raw materials were investigated by using SEM-EDS, RX and DTA-TG curves. The samples were analysed from the mineralogical, technological and mechanical points of view. The result show that the tuff’s presence in the clay mixtures considerably reduced the shrinkage of the product during the firing process, and the manufactured samples were of excellent quality. The compressive strength of the bricks varied from 5–35.3MPa, being influenced by the tuff content, clay matrix properties and firing temperatures. Finally, the heat demand for increasing the temperature from room to the firing temperature of the sample with 10% tuff content was 22%.

No abstract

This study investigates the effect of adding different size fractions of the same pore forming agent (sawdust) on the material’s compressive strength and heat transfer. The samples were dry pressed and fired at high temperature inside an oven. Phase transformations were evidenced by a combination of differential thermal analysis, thermogravimetry and mass spectrometry (DTA-TGA-MS) and X-ray diffraction (XRD) techniques, in the temperature range of 24-900 ºC. Image analysis (IA) and compression tests were performed to explain the mechanical behaviour of the samples. The thermal conductivity was obtained by using combined photopyroelectric calorimetry (PPE) and lock-in thermography (LIT) techniques. The pressing direction has an impact on the distribution of pores and the heat transfer by conduction.

No abstract