Influence of particle size on the pozzolanic reactivity of waste clay brick accessed by R³ test

Influência da granulometria sobre a reatividade pozolânica do resíduo de bloco cerâmico utilizando Teste R³

Abstract

The inclusion of wastes of clay brick (WCB) as a supplementary cementitious material (SCM) demands a processing process guided by the reactivity of the material. In this sense, the present study evaluated the influence of particle size on the pozzolanic reactivity of WCB. WCB of five distinct particle size distributions was compared to metakaolin, natural clay, and waste of clay tile (WCT). The assessment of pozzolanicity was based on the R³ reactivity test, using isothermal calorimetry and quantification of bound water content, in addition to the compressive strength and analysis by XRD/Rietveld of composite cement pastes type CPII-Z and CPIV. Reducing the D_90% diameter of the WCB from 33 to 11 µm promoted an increase of 50% in pozzolanic reactivity. However, for D_90% diameters below 11 µm, the increase in reactivity (2%) may not justify the costs associated with prolonging the grinding process. The results highlighted the feasibility of using the R³ test and the importance of beneficiation guided by reactivity, aiming to optimize the recycling potential of new materials in the production of composite cements.

Keywords
Ceramic waste; Supplementary cementitious materials; Pozzolanic reactivity; Composite cements