AN INVESTIGATION ON THE EFFECTS OF TEMPERATURE CHANGE ON AGGREGATE CHARACTERISTICS IN PERLITE EXPANSION - A NEW APPROACH

Abstract

In this study, the changes in the expanded aggregate forms formed after the expansion process of raw perlite at different temperature values in an equivalent time were analyzed and the factors affecting the structural characteristics of the expanded perlite were examined. Especially after expansion process, a new approach has been examined to represent strength, fragility, and crumbling phenomenon of the perlite aggregate. In the study, raw perlite in 125-250 µm, 250-500 µm and 500-750 µm size ranges was used and the expansion temperatures were 200, 360, 410, 480, 530, 560, 590, 610, 640, 660, 690, 730, 760, 830, 900 and 1040 ˚C, respectively. According to the results, it was determined that as expansion temperature of the raw perlite increased, bulk density of the expanded perlite decreased, and grain size increased. It was observed that as the maximum grain size increased, the collapse (deformation) values increased when interacted with water due to the difference in the changing matrix structure of expanded perlite. Compressive strength and workability decreased with increase in the collapse rate of the expanded perlite aggregate in cementitious mortars. Although workability and strength of the mortars produced with perlite aggregate expanded at high temperature decreased with the effect of collapse, it was determined that the thermal performance of the mortar produced with this type of aggregate improved.