Evaluating the properties and mineral phases of the expanded clay aggregates with the bentonite additive material

Abstract

Additive materials are the perfect solutions to improve the physical, mechanical and expansion properties of lightweight expanded clay aggregates (LECA). This work focused on studying the effect of bentonite materials on physical, mechanical, expansion properties and mineral phases of expanded clay aggregates. Samples were collected from Mályi quarry Miskolc, Hungary. These samples were studied by XRF, XRD, SEM and heating microscope. In addition, the physical and mechanical properties of specimens were measured according to relating standards. Results showed that, addition of bentonite material to the clay samples has great effect on bulk density, sintering and melting point and compressive strength of the aggregates. By using the three different amounts (5 %, 10 % and 20 %) of bentonite with the LECA, compressive strength of the aggregates was enhanced by 48 % to 112 % compared to aggregates without bentonite. 10 % of bentonite with aggregates was enhanced the height expansion of the aggregates by 50-68 %. In addition, 10 % of bentonite with LECA was most crucial, which decreased bulk density of aggregates by 5 % to 20 % compared with other added amounts of bentonite. According to XRD analysis, hercynite was one of the phases, which can control compressive strength of aggregates.