Study of the pozzolanic activity of thermally modified clay rocks

This study presents obtaining a new highly active pozzolanic additive based on local raw materials. Heat treatment of clay rocks was carried out in a laboratory muffle furnace. The X-ray phase analysis were carried out using a Dron-4.0 diffractometer (''Burevestnik'', St. Petersburg, Russia) with a Cu-anode and a Ni-filter. U=35kv. I=20mA. Intensity - 2 degrees / min. λ = 1.54178 Å. For thermogravimetric analysis, a NETZSCH derivatograph with STA-2500 REGULUS thermogravimetric and differential thermal analyzer (TG / DTA) was used. Samples were heated to 1000 ℃, in a ceramic crucible, heating rate 10 ℃ / min. Reference substance a-Al₂O₃. Pozzolanic activity was determined according to the GOST R 56593 method. The optimal mode of heat treatment of clayrocks was established, which made it possible to increase their pozzolanic activity. Based on the studies, local clay rocks were identified, which, after heat treatment - thermal modification according to a certain regime, can be used as a highly active pozzolanic additive to cement, which will reduce the proportion of clinker in cement without decline the mechanical strength of the latter. As such, we can consider: shale from the Durudzhi River modified at a temperature of 800 ℃, mudstone from Teleti, clays from Metekhi, Miriani and Gardabani - modified at a temperature of 700 ℃. (author)