Fired porous clay granulates - for replacing sand or aggregate in concrete mfr.

摘要

Ceramic granulates are made by firing a clay or a day mixt. to give a porosity of 10-35 (25-35)% and a pore distribution such that 60-90% of the pore fire between 0.75 and 20 (0.75-5)u dia. The granulates, which may be =5 mu or =5 mu, are made by normal methods of preparing clay for brick and tile mfr., extruding to for cylinders of various dias., drying and firing at 10-50-1200 degrees C, in a rotary grid furnace. For the finer material the layer particles produced are crushed and ground appropriately. The clay pref. contains 10-18% CaO. The pores can contain a reserve of water which favours correct hydration of the cement, growel mixt. during setting, giving improved adhesion and increased compressive strength e.g. of the order of 2 kb.